Elastic–plastic behavior of a shallow two bar truss

2020

Particular features and traits of a model of large deformations applied for static analysis and design of metal structures with plasticity are considered. Foundations of the deformation theory of plasticity relevant for incompressible materials are formally generalized for the model of hyperelastic body described by equation of state in the Finger form. The behavior of the model is analyzed for the case of uniaxial tension. The collected results are used to explore a symmetrical three-bar truss made of two materials. Relations describing behavior of the truss under conditions of the geometric and physical nonlinearities are obtained. Specifics arising in the analysis and design of the truss using standard structural alloys are analyzed.

Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XI, Construcţii navale/ Annals of "Dunărea de Jos" of Galati, Fascicle XI, Shipbuilding, 2015

This papers aims mainly at presenting the effects of loads acting upon the structure of a truss bar and at pointing out the positioning modes of stress concentrators. Moreover, the papers highlights the way in which the factor of stress concentration is determined and how the results are established in order to determine the best software to analyse the beam for further possible optimization.

Vibroengineering procedia, 2022

The paper presents the natural frequencies shift of a Warren truss with seven elements in the case that members of the structure are weakened by considering that the modulus of elasticity with a lower value. Taking into consideration that the slenderness ratio has a constant value and the transverse section of the truss bars is changed, the relative frequency shift for the first seven vibration mode were calculated by using the values obtained from numerical modal analysis. The conclusions reveal the fact from the dynamic behavior of the structure it can be obtained templates to identify the weakened truss bar of the structure.

IOP Conference Series: Materials Science and Engineering, 2017

This research studies the lateral buckling behavior in truss and lateral buckling coefficient of truss. Lateral buckling analysis of truss is performed by simulating the structural model with both end supports being pinned and roller-supports. The analysis is indirectly conducted using Elastic Theory to evaluate the length of lateral buckling by calculating the determinant of the Matrix [K]. Results from the analysis are marginally different from those obtained from finite element program and are considerably less than those obtained from Eurocode standard. This can be concluded that using elastic theory to evaluate lateral buckling coefficient of truss member will result in more economical section. 

Journal of Materials Science and Chemical Engineering, 2021

This paper presents a simplified numerical simulation tool for the elasto-plastic calculation of plane articulated truss by the finite element method (FEM) in MATLAB. The simplified approach consists of linearizing isotropic strain-hardening (to obtain a bilinear material law). The numerical implementation is built on the basis of the incremental and iterative FEM algorithms. The numerical resolution technique used is based on the projection methods of the modified Newton-Raphson solution. The MATLAB program is developed for the application of a 3-bar truss under monotonous quasi-static loading. Different values of the approximation error of the convergence criterion are used to study its impact on the quality of the algorithm. Numerical simulations have shown the reliability and quality of our simplified approach regardless of the approximation error.

Applied Mechanics and Materials, 2015

In the present paper, the Preisach model of hysteresis is extended to structural analysis of trusses damaged under cyclic loading in plastic range. Parameters for the Preisach model of cyclic plasticity are obtained from uniaxial loading experiment. Damage, as a consequence of micro cracks appearance due to alternating loading in plastic domain, is modeled using brittle elements according to Preisach procedure. Results of this research are compared with the already existing in the literature. In the paper examples of trusses under various cyclic loadings are presented.

In this work an investigation was carried out on the implications of analyzing wielded trusses as pin-jointed on the weight and by extension on the cost of the structure. Different trusses were studied and the effect of secondary stresses (bending moments induced by joint rigidity) on the final weight of the structure determined. The trusses were first analysed as pin-jointed and later as having rigid joints. The sizes of the truss elements were assumed to be proportional to the axial force in it. By considering the elements of the truss to be of a constant breadth b, the required depth of the section becomes representative of the size of the element. To convert it to weight the calculated depth for each element is multiplied by the corresponding length of the element. This quantity was compared for pin-jointed and rigidly connected joints. From the obtained results it was observed that the rigidly connected (wielded) truss requires a lighter and hence cheaper structure than the pin-jointed truss. In conclusion it was observed that the wielded joints substantially increased the load carrying capacity of the truss.

International Journal of Solids and Structures, 2019

The present work investigates, using a corotational finite element formulation considering large displacements and rotations, geometric imperfections and an elasto-plastic material constitutive law, the nonlin-ear behavior of a pyramidal space truss under vertical and horizontal loads. Additionally novel analytical closed-form solutions for the nonlinear equilibrium paths, natural frequencies and critical parameters are derived for comparison purposes and investigation of the influence of geometric and material parameters on the truss stability. This geometry has an immediate practical interest since these structures are currently used in many present-day applications, either as main structural component or as a constitu-tive element. Four types of nonlinear instability phenomena are investigated theoretically and numerically: saddle-node (limit point) bifurcation, pitchfork bifurcation, individual Eulerian bars buckling and elasto-plastic buckling. Through a detailed parametric analysis the interaction between these buckling phenomena, using the FE tool, is investigated. In addition, the effect of elastic supports is considered. The influence of these phenomena on the load carrying capacity of the structure and its imperfection sensitivity is duly discussed in the present work. Finally, a detailed parametric analysis of a large roof composed of pyramidal truss units is conducted and the influence of the geometric parameters on its bistable behavior and load carrying capacity is investigated.

Journal of Civil Engineering and Architecture, 2019

The paper presents results of calculations of forces in members of selected types of statically indeterminate trusses carried out by application of the two-stage method of computations of such structural systems. The method makes possible to do the simple and approximate calculations of the complex trusses in two stages, in each of which is calculated a statically determinate truss being an appropriate counterpart of the basic form of the statically indeterminate truss structure. Systems of the statically determinate trusses considered in the both stages are defined by cancelation of members, number of which is equal to the statically indeterminacy of the basic truss. In the paper are presented outcomes obtained in the two-stage method applied for two different shapes of trusses and carried out for various ways of removing of appropriate members from the basic trusses. The results are compared with outcomes gained due to application of suitable computer software for computation of the same types of trusses and for the same structural conditions.

Zbornik radova Građevinskog fakulteta, 2014

In the present paper, implememtation of Preisach model of hysteresis to elastoplastic analysis of trusses subjected to cyclic is shown. It is also shown that damage effects can be included in presented analysis by introducing basic concepts of continuum damage mechanics. Using finite element method, equilibrium equations are obtained and algorithm for numerical solution is defined. Some advantages of this approach are underlined through several numerical examples.