Finite Element Analysis (Engineering)

Static loadings resistance is always the first design criteria. However, further investigation should also be conducted for a structure like floors, bridges, and stairs which are subjected to dynamic loadings in the form of human activities such as walking, running, or jumping; these loadings often result in vibrational effects associated with the user’s comfort. While most researches were mostly about walking force on flat surfaces, this study will mainly focus on reinforced concrete cantilever staircase which has been reported to encounter a significant level of vibration due to periodic walking motion. Therefore, this paper presents the attempt to study the characteristics and response of RC cantilever stair design once being subjected to human-induced vibration and to propose the application of extra reinforcing steel used to lessen the dynamic effects. Numerical analysis is done on an RC cantilever stairs model having dimensions of 100 centimeters in length, and 25 centimeters ...

In Vietnam, 102 species with 19 geniuses of bamboo families are recorded. But the most popular is Dendrocalamus membranaceus Munro. It has been selected forestation in the provinces from the North Central to Central area of Vietnam. Fabricated bamboo fibers by mechanical and steam exploded techniques consist of short and long fibers. Different methods of bamboo fiber surface treatment have been carried out and alkaline treatment was the best method. Thermoplastic resin (polypropylene -PP) and thermoset resin (unsaturated polyester -UP and epoxy -EP) were used as matrices of composites. Maleic anhydride grafted polypropylene (MAPP) was chosen as coupling agent to improve adhesion between PP and bamboo fiber. Polymer composite materials were reinforced by only bamboo fiber according to skin-core and ply-by-ply structure. Bamboo-PP resin composites with 50 wt. % of bamboo fiber has higher mechanical properties in comparison with pure PP. Bamboo-UP resin composites possess good mechanical and chemical properties, whereas bamboo-EP resin composites show unsatisfied water and chemical resistance. Skin-core structure hybridization of jute with glass fiber in skin increased impact strength significantly (1.8-2.0 times). This hybrid composite was used for making chair, tables, boats, construction panels, etc Short bamboo fiber-PP composites are going to prepare pall rings using for waste water treatment in the present of micro-organism.

This report deals with nonlinear finite element analysis of concrete structures loaded in the short-term up until failure. A profound discussion of constitutive modelling on concrete is performedj a model, applicable for general stress states, is described and its predictions are compared with experimental data. This model is implemented in the AXIPLANEprogram applicable for axisymmetric and plane structures. The theoretical basis for this program is given. Using the AXIPLANEprogram various concrete structures are analysed up until failure and compared with experimental evidence. These analyses include panels pressure vessel, beams failing in shear and finally a specific pull-out test, the Lok-Test, is considered. In these analyses, the influence of different failure criteria, aggregate interlock, dowel action, secondary cracking, magnitude of compressive strength, magnitude of tensile strength and of different post-failure behaviours of the concrete are evaluated.

Indonesia belakangan ini sering mengalami bencana alam gempa bumi karena berada diantara tiga lempeng bumi yaitu lempeng Pasifik, Eurasia, dan Indo-Australia. Untuk mengantisipasi terjadinya kerusakan yang berat, maka diperlukan bangunan yang kuat dan tahan terhadap gempa. Perlu dilakukan pemasangan bracing dengan eksentrisitas (EBF). Maka, diperlukan penelitian lebih lanjut untukk mengetahui efektifitas bracing yangg memiliki eksentrisitas. Dalam penelitian ini dibuatt tigaa  benda uji. Benda uji tersebut berupa portall betonn sederhanaa yang terdiri dari balok, kolom, dan bracing tipe V. Benda uji  memiliki tinggii 70 cm dan panjang 100 cm. Bracing pada benda uji  pertamaa tidak memiliki eksentrisitass. Sedangkan untukk bendaa uji  lainnya diberikan eksentrisitas pada sisii bawahnya  masing-masing 15 cm, dan 25 cm. Benda uji portal  dibuatt menggunakan  tulangann utama O6 dan sengkang O4. Pengujiann dilakukan dengan menggunakann alat  loadd celll untukk memberikan beban lateral, a...

Some numerical models are proposed for simulate the aircraft tyre behaviour on the ground in critical situations. Fully coupled thermo-mechanical analysis procedures taking into account finite deformation, dynamics and frictional contact are studied. The proposed models are compared with experimental data such as contact area, lateral and longitudinal stiffnesses, surface temperature evolution due to friction, self-alignment torque, and lateral friction coefficients. A good agreement is observed at low speed (less than 70 km/h). Thus, the model is extrapolated to high speeds and seems able to predict results in cases for which it is not possible to obtain realistic experimental data.

This study investigates the impact of various element and concrete material models on the finite element analysis (FEA) of reinforced concrete (RC) structures. A comparative evaluation was conducted using 1D, 2D, and 3D finite element models. The research includes the numerical modeling of an experimentally tested RC beam with different finite element and concrete material models. The modeling process was carried out using DIANA FEA software, and the results were compared with experimental data. Furthermore, a parametric analysis was carried out to evaluate the impact of mesh size. Although mesh size varies depending on the element type and geometric properties, the study provides valuable insights for selecting appropriate mesh refinement in similar analyses. The results indicate that the most accurate element model is the 3D model, while the Eurocode concrete model exhibited the best agreement with experimental results. However, other concrete models also demonstrated reasonable accuracy. It was concluded that selecting the smallest feasible mesh size, within the constraints of computational efficiency and analysis requirements, leads to improved numerical accuracy.

The effective electric resistivity of conductive thermoplastics manufactured by filament extrusion methods is determined by both the material constituents and the printing parameters. The former determines the multifunctional nature of the composite, whereas the latter dictates the mesostructural characteristics such as filament adhesion and void distribution. This work provides a multi-scale computational framework to evaluate the thermo-electro-mechanical behaviour of printed conductive polymers. A full-field homogenisation model first provides the influence of material and mesostructural features (i.e., filament orientations, voids and adhesion between filaments). Then, a macroscopic continuum model elucidates the effects of thermo-electro-mechanical mixed boundary conditions. The in-silico multi-scale methodology is validated with extensive original multi-physical experiments and a functional application consisting of an electro-heatable printing cartridge. Overall, this work establishes the foundations to virtually break the gap between mesoscopic and macroscopic multifunctional responses in conductive components manufactured by additive manufacturing techniques.

Prediction of hydrogen embrittlement requires a robust modelling approach and this will foster the safe adoption of hydrogen as a clean energy vector. A generalised computational model for hydrogen embrittlement is here presented, based on a phase field description of fracture. In combination with Part I of this work, which describes the process of hydrogen uptake and transport, this allows simulating a wide range of hydrogen transport and embrittlement phenomena. The material toughness is defined as a function of the hydrogen content and both elastic and elastic-plastic material behaviour are incorporated, enabling to capture both ductile and brittle fractures, and the transition from one to the other. The accumulation of hydrogen near a crack tip and subsequent embrittlement is numerically evaluated in a single-edge cracked plate, a boundary layer model and a 3D vessel case study, demonstrating the potential of the framework. Emphasis is placed on the numerical implementation, which is carried out in the finite element package COMSOL Multiphysics, and the models are made freely available.

In heavy-duty material handling equipment, major concern is optimum utilization of material for equipment construction without sacrificing the design parameters. To understand this aspect and also to validate the design, as this kind of equipment are vital part of any manufacturing industry, finite element analysis is one of the best method that can be used extensively. This paper work provides a modeling of the structural strength of a crane bridge, in operation for 15 years in the continuous casting department of a steel plant. Due to the importance of the cranes bridge within the technological processes in which they are involved, either from the point of view of steel consumption or functionality, their resistance calculation, during the design phase and after a certain operation period, constitutes a permanent field of investigation which aims a faithful schematization to be used in further modeling, appropriate for our target. Modeling will be done with the aid of a COSMOS/M s...

El Fuerte de Samaipata, commonly known as Samaipata, is an archaeological site in Bolivia. It was inscribed on the UNESCO World Heritage List in 1998. The most characteristic feature of the site is a natural rock that served as a wak'a (sacred place) for several local, pre-Hispanic cultures, so its current condition is the result of at least 1200 years of development. Towards the end of the 20 th century and beginning of the 21 st century, Samaipata was comprehensively studied and documented by German scholars. Due to the threat of progressing erosion, a new documentation project was executed by a Polish team. The main objective of the project was to document the vanishing site using 3D laser scanning. Most of the research already published on Samaipata concentrates on the complex arrangement of niches and terraces, figural and geometrical petroglyphs, as well as canals and water reservoirs at the site. The long rows of small circular holes drilled into the rock attract less scholarly attention. They are commonly associated with the vertical posts used for traditional quincha walls. Since there are doubts about the ability of the quincha wall to resist the extremely strong winds on the top of the rock, the Authors conducted computer simulations to clarify these reservations. The 3D model was based on 3D laser scanning results, while FEM was used to solve structural analysis problems.

In previous published literatures it was stated that superposition law might be valid for ground improvement techniques consisting of prefabricated vertical drains (PVDs) along with surcharge and vacuum preloading. Even some professional geotechnical engineers might think of this false idea that superposition law might be valid in such ground improvement techniques. It was shown that the superposition law is not valid because of the hydro-mechanical coupling interactions which exist between vacuum and surcharge preloading. A case history was presented and Finite element modeling (FEM) was used for verification and the demonstration of coupled consolidation interaction between vacuum and surcharge preloading. Three main parameters as settlement, lateral displacement, and excess pore pressure were evaluated for different scenarios. The results that are based on a macro-element approach can be used for better comprehension of the working mechanism of combined treatment systems. Considering the results of this literature, a complex combined vacuum and surcharge preloading can be broken in simpler cases that can be used for either deriving analytical or empirical solutions.

Convolving the output of Discontinuous Galerkin (DG) computations with symmetric Smoothness-Increasing Accuracy-Conserving (SIAC) filters can improve both smoothness and accuracy. To extend convolution to the boundaries, several one-sided spline filters have recently been developed. We interpret these filters as instances of a general class of position-dependent spline filters that we abbreviate as PSIAC filters. These filters may have a non-uniform knot sequence and may leave out some B-splines of the sequence. For general position-dependent filters, we prove that rational knot sequences result in rational filter coefficients. We derive symbolic expressions for prototype knot sequences, typically integer sequences that may include repeated entries and corresponding B-splines, some of which may be skipped. Filters for shifted or scaled knot sequences are easily derived from these prototype filters so that a single filter can be re-used in different locations and at different scales. Moreover, the convolution itself reduces to executing a single dot product making it more stable and efficient than the existing approaches based on numerical integration. The construction is demonstrated for several established and one new boundary filter.

La subdivision de l'element parent en sous-cellules d'integration utilisee dans le cadre de la methode X-FEM convient difficilement a l'etude de la propagation d'une fissure dans un milieu plastifie. Il est alors notamment necessaire de realiser la projection des variables internes aux points d'integration des sous-elements. Cette contribution etend au cas de la plasticite une methode d'integration utilisant les formules de quadrature de Gauss standards, initialement developpee dans le cadre de l'elasticite lineaire. La methode proposee se limite aux cas des interfaces et des elements lineaires.

Nous présentons une implémentation X-FEM capable de représenter des conditions de contact et frottement pour des surfaces de failles dans des bassins sédimentaires. Ces failles constituant des réseaux avec intersections, nous définissons un enrichissement du champ de déplacement qui représente les jonctions entres ces surfaces de discontinuité. Pour satisfaire la condition LBB sur l'espace des inconnues de contact par rapport aux inconnues de déplacement, nous proposons d'utiliser une interpolation P 0 sur les jonctions. Un cas d'application d'un bassin sédimentaire démontre la robustesse de la méthode. Mots clés -X-FEM, contact, frottement, LBB, failles.

It is a well-known fact that incorporating a slip boundary into the contact surfaces improves bearing performance significantly. Regrettably, no research into the effect of slip on the behavior of journal bearing systems operating with non-Newtonian lubricants has been conducted thus far. The main purpose of this work is to explore the performance comparison of Newtonian and non-Newtonian fluid on a heterogeneous slip/no-slip journal bearing system. The tribological and acoustic behavior of journal bearing is investigated in this study using a rigorous program that combines CFD (computational fluid dynamics) and two-way FSI (fluid–structure interaction) procedures to simulate Newtonian vs. non-Newtonian conditions with and without slip boundary. The numerical results indicate that irrespective of the lubricant type (i.e., Newtonian or non-Newtonian), an engineered heterogeneous slip/no-slip pattern leads to the improvement of the bearing performance (i.e., increased load-carrying ca...

Total hip replacement (THR) is normally done for the failure of hip joint caused by osteoarthritis. It is performed to relief pain and to improve functionality. Issues related to the study include method to reduce fixation failure, means to improve the longevity of the prosthesis, methods to reduce the factors contributing to probability of failure such as cement strength, implant interface strength, and loosening. The present work focused on failure related to stress related only. The main aim of this work is to study the inner failure stress for THR and to suggest recommended functional activities for patient whom undergoes THR. By knowing the stress for the inner bone, the failure mechanisms of THR for different dynamics loadings can be predicted more objectively. For this study, ANSYS Workbench version 11.0 was used for the Finite Element (FE) analysis. The values of stress and strain distributions in anterior (A), posterior (P), medial (M) and lateral (L) positions of the healthy femoral bone and THR were obtained. The stress and strain distributions of inner healthy femoral bone surface subjected to standing were studied. The effect of materials on the variations of stress and strain of the outer and inner surface of the

Designers are continuously challenged to manage complexity in embodiment designprocesses, in the context of integrated product and materials design. In order to manage complexity in design processes, a systematic strategy to embodiment design-process generation and selection is presented in this paper. The strategy is based on a value-ofinformation-based Process Performance Indicator. The approach is particularly well-suited for integrated product and materials design, and all other scenarios where knowledge of a truthful design-process and bounds of error are not available in the entire design space. The proposed strategy is applied to designing embodiment design-processes for multifunctional blast resistant panels. It is shown that the proposed strategy based on the Process Performance Indicator is useful in assessing the performance of embodiment designprocesses particularly when knowledge of prediction accuracy or its error bounds is not known throughout the whole design space. B in-plane spacing of webs of square honeycomb core BRP blast resistant panel d i + , d i deviation variables for goals in cDSP cDSP compromise decision support problem h c , h f , h b thickness of core webs and face sheets, respectively δ, ∆δ deflection of back face, variance in deflection of back face c ε

Subsonic airplanes are widely used around the world in applications such as pilot training, transportation, sports activities, insect fighting, and field monitoring. This research deals with airplanes that already own the capability of carrying suspended loads. Increasing the airplane's capabilities and configurations by integrating different suspended loads like smaller or larger external fuel tanks or insecticide tanks that are not in the original configuration of the airplane is a great advantage. This modification can be done without dramatic changes to the airplane and with minimum cost. In this research, a multidisciplinary methodology is used to integrate a commerciallyavailable premade external fuel tank into the Embraer E312 Tucano airplane which is not in the original configuration of the airplane. First, a geometrical analysis is performed to ensure the availability of proper installation. This study leads to the design of an adaptor between the tank and the airplane pylon, then, a computational fluid dynamics (CFD) modeling using ANSYS-CFX is performed to evaluate aerodynamic forces and moments applied on the new fuel tank. Furthermore, finite element modeling using ANSYS-Static structure is performed by applying the aerodynamic and inertial loads to calculate the adaptor's stresses and structure safety factor. Finally, vibration fatigue analysis-based power spectral densities are developed using ANSYS-Random vibration to calculate the adaptor's estimated lifetime to ensure the store system's safety by applying airplane vibration acceleration spectral density pattern selected from applicable standard. In this typical example, the above-mentioned methodology is applied and the results are acceptable.

This study presents the structural effectiveness of fixed offshore platforms, addressing the challenges posed by complex loading conditions in marine environments. The structural performance of the fixed offshore plat- form was assessed using Finite Element Analysis performed in ABAQUS CAE software, with particular fo- cus on the impact of intrinsic stress induced by corrosion and environmental loads such as; wind, waves, and operational activities. The reliability of the fixed offshore platform was also assessed using Monte Carlo’s re- liability method. The study utilized advanced design equations to evaluate the structural reliability and rate of corrosion of the fixed offshore platform in order to estimate the safety of the structure. Results indicated that there are high stress values in the beam and column connections and also in the columns due to the effect of depleting cross-sectional area with respect to time and also the intrinsic stresses as a result of the applied loadings. Hence, selecting a high-grade steel and a higher cross-sectional area for structural members with slow the rate of corrosion and also reduce the intrinsic stresses due to the loadings on the structure.  This will not only improve the load-bearing capacity but also significantly reduced the risk of structural failure, align- ing well with empirical data. Furthermore, the study highlighted the importance of considering the interaction between material properties, connection characteristics, and loading conditions in the design process. These findings contribute to the development of more robust and durable fixed offshore platforms, ensuring their safety and longevity in demanding operational environments.

The analysis of travelling waves in elastic waveguides with complex cross-sections, such as train rails, can only conveniently be performed numerically. The semi-analytical finite element (SAFE) method has become a popular tool for performing such analyses. This paper employs a hybrid SAFE-3D method to investigate the scattering of guided waves interacting with discontinuities, such as welds, in continuous welded train rails. The aim of the analysis is to predict transmission and reflection coefficients for a given incident wave and known discontinuity parameters. This characterisation is useful for predicting the long-range transmission characteristics of transducers in NDT and monitoring systems, such as the rail break alarm system developed by the Institute for Maritime Technology (IMT) and the Council for Scientific and Industrial Research (CSIR). The numerical model can also be used to estimate welded sections properties from experimental measurements using a scanning laser vibrometer.

For intra-cavity laser beam control, a small, low-cost deformable mirror is required. This mirror can be used to correct for time-dependent phase aberrations to the laser beam, such as those caused by thermal expansion of materials. A piezoelectric unimorph design is suitable for this application. The proposed unimorph consists of a copper disc with mirror finish, bonded to a piezoelectric disc. The deformations that the mirror is required to perform are routinely (at least in optical applications) described using Zernike polynomials, which are a complete set of orthogonal functions defined on a unit disc. The challenge is to design a device that can represent selected polynomials as accurately as possible with a specified amplitude. To assist in the design process, numerical modelling is required to predict the deformation shapes that can be achieved by a unimorph mirror with a particular electrode pattern. In this paper a previously proposed axisymmetric Rayleigh-Ritz formulation, is extended to account for non-axisymmetric voltage distributions, and therefore non-axisymmetric displacements. The Rayleigh-Ritz model, which uses the Zernike polynomials directly to describe the displacements, produced a small model (stiffness matrix dimension equal to the number of polynomials used) that predicts the deformations of the piezoelectric mirror with remarkable accuracy. The results using this Rayleigh-Ritz formulation are compared to results from a traditional finite element analysis using a commercial finite element package. Both numerical models were applied to model a prototype deformable mirror and produced good agreement with experimental results.

This paper evaluates key parameters in the view of improving the quality of parts produced during the sheet hydroforming with the die (SHF-D) process. In the hydroforming with die process, effective control and promotion of material formability during drawing have the most decisive role: effective control and facilitation of the metal flow into the die cavity. The next was the form parts die profile radius effect and friction. It has been found that the friction conditions are together with the die profile radius quite significant parameters and have a substantial influence on the quality. In fact, the reduced-friction interface of the sheet against the die increases the ability to gain the form in the desired shape due to the reduction of thinning of the part at critical areas. Improving the forming of the part is also achieved by increasing the die entry radius up to a specific value.

Determination of the dynamic axle loads and wheels loads of the passenger cars is necessary due to their influences on the gripping forces, the conditions at which the stability of the car can be lost, as well at the design stage of the passenger cars, with influence on the braking system, on the axles, but also on their suspension. By comparing the dynamic loads on different classes of the passenger cars, it aims to highlight the parameters which influence the dynamic loads and parameters that influence the maximum grip force. The study of the paper includes: the choice of three different classes of passenger cars and one representative passenger cars for each class considered, in order to determine their dynamic loads; performing the experimental measurements on the determination of the static normal loads on the wheels/axles of the three cars under consideration in order to determine the position of the center of gravity for each of them; the development of numerical modeling to result in dynamic loads, the maximum grip force and the dynamic coefficients for the three passenger cars in different operating situations (starting, braking and in cornering) and for different natures and conditions of the road, respectively different longitudinal and transverse inclination of the road, as well as the comparison of the obtained results with the emphasis of the parameters that have an influence on them. The results are interpreted graphics, enabling a comparative study of them.

Determination of the dynamic axle loads and wheels loads of the passenger cars is necessary due to their influences on the gripping forces, the conditions at which the stability of the car can be lost, as well at the design stage of the passenger cars, with influence on the braking system, on the axles, but also on their suspension. By comparing the dynamic loads on different classes of the passenger cars, it aims to highlight the parameters which influence the dynamic loads and parameters that influence the maximum grip force. The study of the paper includes: the choice of three different classes of passenger cars and one representative passenger cars for each class considered, in order to determine their dynamic loads; performing the experimental measurements on the determination of the static normal loads on the wheels/axles of the three cars under consideration in order to determine the position of the center of gravity for each of them; the development of numerical modeling to result in dynamic loads, the maximum grip force and the dynamic coefficients for the three passenger cars in different operating situations (starting, braking and in cornering) and for different natures and conditions of the road, respectively different longitudinal and transverse inclination of the road, as well as the comparison of the obtained results with the emphasis of the parameters that have an influence on them. The results are interpreted graphics, enabling a comparative study of them.

Abstract: Determination of the dynamic axle loads and wheels loads of the passenger cars is necessary due to their influences on the gripping forces, the conditions at which the stability of the car can be lost, as well at the design stage of the passenger cars, with influence on the braking system, on the axles, but also on their suspension. By comparing the dynamic loads on different classes of the passenger cars, it aims to highlight the parameters which influence the dynamic loads and parameters that influence the maximum grip force.  The study of the paper includes: the choice of three different classes of passenger cars and one representative passenger cars for each class considered, in order to determine their dynamic loads; performing the experimental measurements on the determination of the static normal loads on the wheels/axles of the three cars under consideration in order to determine the position of the center of gravity for each of them; the development of numerical m...

Abstract: Determination of the dynamic axle loads and wheels loads of the passenger cars is necessary due to their influences on the gripping forces, the conditions at which the stability of the car can be lost, as well at the design stage of the passenger cars, with influence on the braking system, on the axles, but also on their suspension. By comparing the dynamic loads on different classes of the passenger cars, it aims to highlight the parameters which influence the dynamic loads and parameters that influence the maximum grip force.  The study of the paper includes: the choice of three different classes of passenger cars and one representative passenger cars for each class considered, in order to determine their dynamic loads; performing the experimental measurements on the determination of the static normal loads on the wheels/axles of the three cars under consideration in order to determine the position of the center of gravity for each of them; the development of numerical m...

Abstract: Determination of the dynamic axle loads and wheels loads of the passenger cars is necessary due to their influences on the gripping forces, the conditions at which the stability of the car can be lost, as well at the design stage of the passenger cars, with influence on the braking system, on the axles, but also on their suspension. By comparing the dynamic loads on different classes of the passenger cars, it aims to highlight the parameters which influence the dynamic loads and parameters that influence the maximum grip force.  The study of the paper includes: the choice of three different classes of passenger cars and one representative passenger cars for each class considered, in order to determine their dynamic loads; performing the experimental measurements on the determination of the static normal loads on the wheels/axles of the three cars under consideration in order to determine the position of the center of gravity for each of them; the development of numerical m...

Abstract: Determination of the dynamic axle loads and wheels loads of the passenger cars is necessary due to their influences on the gripping forces, the conditions at which the stability of the car can be lost, as well at the design stage of the passenger cars, with influence on the braking system, on the axles, but also on their suspension. By comparing the dynamic loads on different classes of the passenger cars, it aims to highlight the parameters which influence the dynamic loads and parameters that influence the maximum grip force.  The study of the paper includes: the choice of three different classes of passenger cars and one representative passenger cars for each class considered, in order to determine their dynamic loads; performing the experimental measurements on the determination of the static normal loads on the wheels/axles of the three cars under consideration in order to determine the position of the center of gravity for each of them; the development of numerical m...

Orthopedic implants require porosity gradients to achieve tissue integration and mechanical support. This study presents a novel design of Multidirectional Functionally Graded (MDFG) porous Ti6Al4V scaffolds, fabricated via Laser Powder Bed Fusion (LPBF) to mimic natural bone porosity for orthopedic applications. Four scaffold types were developed: Gyroid and Primitive (sheet-based TPMS) and Kelvin and Voronoi (strut-based lattices). A pore size of 1000 µm was maintained to promote tissue ingrowth, while strut thickness grading (0.3-0.7 mm) enhanced mechanical stability. Quasi-static compression tests showed Young's moduli of 9.5 GPa (Gyroid) and 9.3 GPa (Primitive), with ultimate strengths of 240 MPa and 190 MPa, respectively. Energy absorption was 47.74 MJ/m 3 for Gyroid and 46.68 MJ/m 3 for Primitive, demonstrating excellent resistance to mechanical failure. Fatigue testing revealed that the Gyroid lattice sustained 25 MPa after one million cycles, highlighting its long-term durability. Fractographic analysis showed that fatigue cracks initiated at surface defects and propagated along strut intersections, providing insights into failure mechanisms. These findings confirm that MDFG scaffolds, particularly Gyroid and Primitive lattices, enhance mechanical robustness and biological compatibility, making them strong candidates for load-bearing orthopedic implants.

After the industrial and the environmental successes of hybridization railways transport, the hybridization of aviation transport is acquiring more and more consideration. In this context, the European Union in partnership with the aerospace manufacturers, has launched in 2014 a largest research program Clean Sky 2 aiming to reduce aircraft fuel consumptions and noise levels. Clean Sky 2 research program includes several projects among of them: Academic reSearch on Thermal & Electric Components & Systems "HASTECS project" which aims to identify and to develop the most promising technologies for decreasing the weight and increasing efficiency of hybrid propulsion chain. "HASTECS project" is organized around six Work Packages (WPs) dedicated to the components of hybrid propulsion chain, for instance, the WP1 is dedicated to electric motors and the WP3 is dedicated to their cooling systems. Indeed, the estimated reduction fuel consumptions for a short range flight would be 3.5% if the specific power of electric machines and power converters with their cooling systems is respectively increased to 5kW/kg and 15kW/kg for 2025, and also increased to 10kW/kg and 25kW/kg for 2035. The targets are significantly higher than those of today. Specific power planned of the industrial electric machines and power converters is higher than the currently one. However, these specific powers present some limitations which depend on the involved material properties and by environment conditions such as: thermal limitations and partial discharges risk. For reaching targeted specific powers for instance in electric machines, the mechanical, electrical and the magnetic loads linked to the materials and cooling technologies must be increased. However, considering the limitations and the environment constraints, choice of loads should be adequate. Therefore, it is important to develop models and tools allowing assessing the actual and the future technologies which allow achieving the HASTECS targets. The present thesis focuses to the development of models and tools for satisfying the HASTECS targets about the electric machines and their cooling systems. There are several different electric machine topologies, namely: radial flux machines, axial flux machines, permanent magnet synchronous machines, wound rotor synchronous machines, asynchronous machines, etc. Performing for each electric machine topology a model for identifying the most promising technologies is a very complex and laborious task. Nevertheless, an analytical model of non-salient sine wave electric machines associated to load ability concepts characterizes a quite lot of electric machine topologies. Based on it, a Target Setting Tool is developed for assessing electric motor technologies considering limits and constraints while without specifying the electric motor topology. Therefore, very few input data are required to make quick trade-offs on electric motor performances as specific power and efficiency whereas Target Setting is based on huge assumptions. For assessing cooling system weight, sizing specified structure of electric motor is unavoidable. Moreover, studies of others work packages are strongly linked to the electric motor structure. Surface Mounted Permanent Magnet Synchronous Motor topology is one of electric motor topology which satisfies the analytical model of Target Setting Tool. A sizing tool called "SM-PMSM" has been carried out based on Surface Mounted Permanent Magnet topology helpful for others packages for providing more details and for checking the Target Setting Tool validity. Two sizing of electric motors with their cooling systems were carried out using Target Setting Tool, SM-PMSM and others tools performed by WP3 to identify the required technologies for the term medium (2025) and long (2035) term HASTECS targets. The sizing using these tools was checked by finite element analysis.

The persistent demand for enhanced mechanical properties in composite materials drives innovation across manufacturing sectors. This study presents a multiscale finite element (FE) analytical approach to explore the mechanical behaviour of a novel hybrid brake disc composed of aluminium composites integrated with carbon nanotubes derived from rice husk (CNTs-RH) and periwinkle shell nanoparticles (PWSnp), utilizing waste aluminium beverage cans as the primary matrix. Through experimental analysis, the developed brake disc exhibited a maximum stress of 15.8402 MPa during braking, with a compressive strength of 410 MPa. Comparative evaluations with existing literature showed that both numerical and experimental results align satisfactorily, confirming the suitability of the mechanical performance for varying percentages of CNT weight. This research not only emphasizes the enhanced attributes of the hybrid composite but also highlights its potential applications in high-performance braking systems, contributing to advancements in material science and sustainable manufacturing practices.

The performance of a machine tool is eventually assessed by its ability to produce a component of the required geometry in minimum time and at small operating cost. It is customary to base the structural design of any machine tool primarily upon the requirements of static rigidity and minimum natural frequency of vibration. The operating properties of machines like cutting speed, feed and depth of cut as well as the size of the work piece also have to be kept in mind by a machine tool structural designer. This paper presents a novel approach to the design of machine tool column for static and dynamic rigidity requirement. Model evaluation is done effectively through use of General Finite Element Analysis software ANSYS. Studies on machine tool column are used to illustrate finite element based concept evaluation technique. This paper also presents results obtained from the computations of thin walled box type columns that are subjected to torsional and bending loads in case of stati...

The alpha magnetic spectrometer (AMS) is a sophisticated instrument developed for the determination of anti-matter nuclei in the outer space. Following specific requirements the silicon sensors are included in an array of several thin carbon fiber composite tubes of different length in various horizontal layers, which will be supported by an outcr vertical cylindrical structure also made in composite. A structural analysis of single tubes and of the complete structure has been performed using a fine element code. The main results of this study are reported in terms of maximum lateral displacement of tubes, suggesting the necessity to use shock absorbers between them; and in terms of vibration behavior expressed as the equivalent Von Misses stresses. The analysis shows that the designed structure accomplish with NASA specifications. where triangular elements were considered. The weight of electronic was considered increasing the density of the outer structure, where it is glued.

Recently, a non-conventional machining technique known as ultrasonically assisted turning (UAT) was introduced to machine modern alloys, in which low-energy, highfrequency vibration is superimposed on the movement of a cutting tool during a conventional cutting process. This novel machining technique, results in a multi-fold decrease in the level of cutting forces with a concomitant improvement in surface finish of machined modern alloys. Also, since the late 20 th century, machining of wear resistant materials that soften when heated have been carried out with hot machining techniques. Turning (HUAT) is introduced for the processing of a Ti-based alloy. In this technique, UAT is combined with a traditional hot machining technique to gain combined advantages of both schemes for machining of intractable alloys. HUAT of the Ti alloy was analysed experimentally and numerically to demonstrate the benefits in terms of reduction in the cutting forces and improvement in surface roughness over a wide range of industrially relevant speed-feed combinations for titanium alloys.

Barajların elektrik üretimi ve sulama gibi alanlarda elde edilecek faydaları ile ülke ekonomilerine katkılarının yanı sıra çevre düzenlemesi, ulaşım ve taşkın koruma gibi alanlarda da faydaları bulunmaktadır. Ancak oluşabilecek aksaklıklar baraj yapılarının yükseklikleri ve aktif depolama hacimlerinin büyüklüğüne göre farklı seviyelerde tehlikeler meydana getirmektedir. Özellikle baraj alanlarına yakın yerleşim bölgeleri için barajlarda oluşabilecek yıkılmanın önceden minimum hata ile tahmin edilebilmesi hayati önem taşımaktadır. Bu çalışma baraj yıkılma modellerinde kullanılan debi tahmin yöntemlerinin temel amaçları, hesap yöntemleri ve uygulama alanları ile elde dilecek sonuçların karşılaştırılmasını içermektedir. Literatürde bulunan ve bu araştırmada incelenen yöntemler tarihi baraj yıkılma verilerine istatistiksel regresyonlar uygulanarak elde edildiği için bazı durumlarda yetersiz kalmaktadır; özellikle bu verilerin elde edildiği baraj türlerinin (baraj yüksekliklerinin) tüm barajları içermemesi sebebiyle önerilen regresyon denklemlerinin yüksek belirsizlikleri olduğu görülmektedir.

Le défi actuel en maintenance est de pouvoir détecter une avarie sur une machine avant qu’elle ne soit grave, et ne provoque son arrêt, ou celui du système de production tout entier. La détection précoce des défauts par apprentissage automatique est devenue l’une des priorités majeures pour beaucoup de chercheurs au cours de ces dernières années. Cependant, l'utilisation des algorithmes d’apprentissage nécessite une quantité considérable de données. C’est qui est difficile à obtenir au niveau industriel et limite l’utilisation de la méthode aux processus ayant une longue durée de vie.  Grâce aux techniques de modélisation, l'utilisation d’un jumeau numérique peut être considérée comme une solution alternative au problème des données. Cependant, les hypothèses simplificatrices et les erreurs de modélisation induisent un biais entre le modèle et le système physique à surveiller.  On fait souvent recours au recalage par identification paramétrique pour la minimisation de l’erreur quadratique entre les deux modèles. Cependant, les différentes méthodes de recalage appliquées jusqu’à présent, révèlent la présence d’une résistance à la minimisation de l’erreur. Pour répondre à cette problématique, nous proposons dans ce travail une nouvelle approche de recalage en deux étapes. Le premier étage consiste à la minimisation de l’écart entre les deux modèles en se basant sur l’optimisation des paramètres du réducteur à engrenages. À laquelle on ajoute un deuxième étage qui permet, non seulement de recaler le jumeau numérique, mais aussi de mesurer le défaut. Pour sa validation, cette approche est testée sur 4 niveaux de fissure (10%, 20%, 30% et 50%) et la mesure du défaut pour chaque cas présente des très faibles écarts. L’utilisation du Kurtosis comme cible du deuxième étage permet de réduire également l’écart entre les autres indicateurs tels que le Facteur de crête, la RMS, Peak et Peak-to-Peak. Ces résultats montrent que l’application de la méthode permet l’amélioration de l’efficacité de la surveillance par jumeau numérique en termes de la réduction de son écart avec le système physique au niveau d’amplitudes et au niveau d’indicateurs. 

Mots clés : Engrenage, fissure, Jumeau numérique, Recalage, amplitude, Indicateur scalaire, Mesure du défaut.

The aim of the present paper is to study calculate the stresses in Knuckle joint using analytical method. Further study in this direction can made by using various directions of the pin and the capacity to withstand load. It is also to be noted that instead of mild steel pin we can also use high strength high modulus steel pin that can further enhance the capacity to withstand higher loads. The shape of the knuckle joint can be changed for improved properties. One can carry out the analysis by changing the shape in the part in the knuckle joint in order to conserve materials and energy. The knuckle joint is proposed to develop in the present study is for an applied force of 25 KN. The diameter of the pin is proposed to be around 23 mm. The material of the knuckle joint is considered as mild steel grade 30C8, in order to do the stress analysis; mesh was developed for the knuckle joint. The mesh consists of 64229 nodes and 4310 elements. ANSYS software was run and the stress contour, displacement contour, strain energy contour were obtained. Based on the ANSYS analysis it shows that a pin of 23mm diameter can withstand a load of 25 kN if we use a factor of safety of 2. Further optimization of the diameter of pin, it depicts that a pin of 12 mm is enough to withstand a load of 25 kN. however if we use a pin of 25 mm the range of pulling load can be enhance to even 80 kN.

The objective of this manuscript is to develop, for the first time, a mathematical model for the prediction of buckling, postbuckling, and nonlinear bending of imperfect bio-inspired helicoidal composite beams with nonlinear rotation angle. The equilibrium nonlinear integrodifferential equations of imperfect (curved) helicoidal composite beams are derived from the Euler–Bernoulli kinematic assumption. The differential integral quadrature method (DIQM) and Newton-iterative method are employed to evaluate the response of imperfect helicoidal composite beams. Following the validation of the proposed model, numerical studies are performed to quantify the effect of rotation angle, imperfection amplitude, and foundation stiffness on postbuckling and bending behaviors of helicoidal composite beams. The perfect beam buckles through a pitchfork bifurcation. However, the imperfect beam snaps through the buckling type. The critical buckling load increases with the increasing value of elastic f...

Fractographic analysis has been used to investigate the fracture behavior of Computer-aided design/ computer-aided manufacturing (CAD/CAM) composite crowns by subjecting them to compression tests. However, it is difficult to investigate details of the fracture, including its initiation and propagation, using in vitro tests. The aim of this study was to determine the fracture origins and the order of crack initiation of CAD/CAM composite crowns using in silico nonlinear dynamic finite element analysis (FEA). The following materials were used: Cerasmart (CS), Katana Avencia Block (KA), and Shofu Block HC (HC) as CAD/CAM crowns, Panavia SA Cement Plus (SA) as a luting material, and Clearfil DC Core Plus (DC) as an abutment. The elastic moduli and fracture strain of each material were obtained from the stress-strain curve of in vitro three-point bending tests. The fracture origins and order of crack initiation of the materials were determined by in silico nonlinear dynamic compression analysis. Load-displacement curves were statistically compared with the results of the in vitro compression tests (Pearson's correlation test, α = 0.05). The nonlinear dynamic FEA demonstrated that crack initiation was primarily observed near the lingual side of the CAD/CAM crowns and immediately propagated to the central fossa. The models were fractured following the in vitro fracture strains, showing the same order for the products tested (CS/KA/HC, SA, and DC). Load-displacement curves with the use of CS, KA, and HC were significantly correlated to the corresponding in vitro compression tests results (CS: r = 0.985, p < 0.05, KA: r = 0.987, p < 0.05, and HC: r = 0.997, p < 0.05). The in silico model established in this study clarified the crack initiation of the CAD/CAM composite crowns and the order of crack initiation among the investigated products, suggesting that the present approach is useful for analyzing the fracture behavior of CAD/CAM composite crowns in detail.

We construct a one-dimensional first-order theory for functionally graded elastic beams using the variational-asymptotic method. This approach ensures an asymptotically exact onedimensional equations, allowing for the precise determination of effective stiffnesses in extension, bending, and torsion via numerical solutions of the dual variational problems on the cross-section. Our theory distinguishes itself by offering a rigorous error estimation based on the Prager-Synge identity, which highlights the limits of accuracy and applicability of the derived one-dimensional model for beams with continuously varying elastic moduli across the cross section.

İnsanlık, belki de var olduğu ilk günden bu yana, hep bir şeyleri merak etmiş, incelemiş ve bulduklarıyla yetinmeyip araştırmaya devam etmiştir. Hiç bitmeyen bu merak ve araştırmalar sonucu bulduklarına yenilerini eklemiş ve teknoloji kavramının ortaya çıkmasını sağlamıştır. Ekonomideki gelişimlerin başlıca temel dayanağını teknolojik yeniliklerin sunmuş olduğu fırsatlar oluşturmaktadır. Malzeme teknolojisi açısından teknolojik gelişmelerin ilk basamağını malzeme özelliklerinin incelenmesi teşkil etmekte ve bu özellikler diğer bir tabir ile davranışlar malzemelerin içyapılarından etkilenmektedir. Malzeme içyapıları imalat esnasında uygulanan ısı ve deformasyondan etkilenerek değişim gösterebildiklerinden, imalat süreci sonunda malzeme özellikleri başlangıç malzemesinden ya da tasarımda dikkate alınandan farklı olabilmektedir. Bu çalışmada, çeliklerin sıcak yığma işlemi esnasında ve sonrasında mikro yapı değişimlerine ait literatürde bulunan ve kabul edilen malzeme modelleme kriterleri incelenmiştir. Ardından 1040 çeliği üzerinde yapılan çeşitli sıcaklıklardaki sıcak yığma deneyleri sonrasında numunelerin sertlikleri, mikro yapı görünümleri incelenmiş, sonuçlar modellemeler ile karşılaştırılmış ve irdelenmiştir. Öncelikle tüm yaşamım boyunca kararlarımın doğruluğuna inanıp bana olan desteklerini hiç esirgemeyen aileme; bilgi, deneyim ve sabrı ile bana rehberlik eden danışman hocam Sayın Doç. Dr. Şafak YILMAZ' a ve varlıkları ile hayatıma anlam katan arkadaşlarım Görkem KIZILTAN, Emrah DENİZ ve Nur PEHLİVANOĞLU' na teşekkürlerimi sunarım.

This paper focuses on the design of steel plated girders under combinations of transverse loading, bending moment and shear force. In the member states of the European Union the design of slender steel plates is covered by EN 1993EN -1-5:2006. Although conclusions from literature show a rather significant interaction between transverse loading and shear force (F-V), no consideration of this type of interaction is made in Section 7.2 of EN 1993EN -1-5:2006. In order to close that gap experimental and numerical studies were undertaken to analyse the stability behaviour and to identify the influence of key parameters. Based on that an F-V proposal is developed which is completed by the consideration of a bending moment so that finally a fully usable F-M-V interaction equation is proposed.

The development of lightweight and high-performance materials has become a pivotal focus in automotive engineering due to the growing demand for energy-efficient and environmentally friendly vehicles. This research focuses on the use of Aluminium Metal Matrix Composites (Al-MMCs) as substitute materials for steel in the design and improvement of leaf springs, which are vital in vehicle suspension systems. By employing CAD modelling and FEA, the mechanical behaviour of the developed Al/SiC MMC and Al/B4C MMC leaf springs are analysed and compared under different static load conditions of 12,500 N & 17,500 N. The analysis focuses on deformation, stress distribution, and weight reduction compared to conventional steel leaf springs. These outcomes indicate that Al-MMCs can achieve up to 60% weight reduction with an improvement or comparable stresshandling capacity. Among all the materials, the stiffness and lower deformation at the maximum load indicate that Al/B4C MMC is a potential material for high-performance and lightweight vehicles. This study focuses on the potential of enhancing Al-MMCs for better fuel economy and vehicle performance by using sustainable automotive material choices. The results of this research will provide possibilities for other high-risk automotive applications of composite material by explaining the behaviour and performance of the material and new designs.

The objective of this paper is to present the most important factors that contribute to the quality and good life expectancy of road pavements. An overview of American and European research dealing with pavement maintenance issues, as related to the design, construction technology, material selection, and improvement of pavement properties, is provided in the paper. Some future trends relating to the extension of life-expectancy of pavements are also presented.

L'effet Trou Noir Acoustique (TN) est une technique passive d'amortissement de vibrations sans ajout de masse fondée sur les propriétés des ondes de flexion dans des structures minces d'épaisseur variable. La mise en oeuvre habituelle consiste en une plaque avec une extrémité profilée selon une loi exponentielle, recouverte d'un film viscoélastique. L'inhomogénéité de la structure conduit à une baisse de la célérité et une augmentation de l'amplitude des ondes de flexion, ce qui a pour conséquence une dissipation d'énergie efficace quand un film amortissant est placé dans la zone de faible épaisseur. Lorsqu'un tel profil est placé à l'extrémité d'une poutre, des caractérisations expérimentales sont possibles à l'aide du coefficient de réflexion ou du recouvrement modal. Des modèles numériques d'une telle structure existent et peuvent aider à comprendre le rôle de la variation d'épaisseur, les effets d'imperfections de fabrication ou encore les effets non-linéaires dus aux faibles épaisseurs.

L'effet Trou Noir Acoustique (TN) est une technique passive d'amortissement de vibrations sans ajout de masse fondée sur les propriétés des ondes de flexion dans des structures minces d'épaisseur variable. La mise en oeuvre habituelle consiste en une plaque avec une extrémité profilée selon une loi exponentielle, recouverte d'un film viscoélastique. L'inhomogénéité de la structure conduit à une baisse de la célérité et une augmentation de l'amplitude des ondes de flexion, ce qui a pour conséquence une dissipation d'énergie efficace quand un film amortissant est placé dans la zone de faible épaisseur. L'amplitude des ondes à l'extrémité peut facilement atteindre l'ordre de grandeur de l'épaisseur de la plaque, ce qui est une source de non-linéarités géométriques. Ces nonlinéarités peuvent avoir pour conséquences des couplages entre les modes de vibration de la structure, et induire un transfert d'énergie des basses fréquences vers les hautes fréquences. Ce phénomène de transfert d'énergie peut être exploité pour augmenter l'efficacité du traitement dans le domaine des basses fréquences pour lequel le trou noir est peu efficace. Une expérience montre que la terminaison TN se comporte de manière non-linéaire et permet un couplage entre modes. Un régime fortement non-linéaire peut également être observé, qui est associé au phénomène de turbulence d'ondes. Une modélisation d'une poutre TN comme une plaque de von Kármán d'épaisseur variable et une résolution du problème par une méthode modale permet de confirmer les effets observés dans l'expérience et d'analyser plus finement ces résultats.

The differences of assessment between musical instruments of the same kind (e.g classical guitars) covers aspects linked to sounds, expressibility, or even manufacturing process. How to extract relevant information related to these aspects by measuring well chosen physical (acoustical, vibratory) parameters ? The aim of the proposed study is to identify criteria enabling the clustering of string instruments in different classes. The plucked instruments will be our application. The knowledge of these parameters would then allow to give an help to the instrument maker in the adjustments and settings likely to be made on an instrument. The modal parameters (frequency, and damping coefficient) can be estimated accurately on a large frequency range from impulse responses by using the high-resolution ESPRIT method, associated with the ESTER criterion to enumerate the signal components. Global parameters, such as the modal density, loss factors and modal overlap factor can be determined and used to estimate average mobility, derived from Skudrzyk's mean-value theorem. The application on guitars and ukulele shows a common behavior of their average mobility: it remains constant in the mid and high frequency domains. The corresponding value is used as one of the parameters enabling the characterization.