Theoretical and numerical analysis of crashworthiness of elliptical thin-walled tube

Key Engineering Materials, 2013

This paper treats the design and analysis of an energy absorbing system. Experimental tests were conducted on a prototype, and these tests were used to validate a finite element model of the system. The model was then used to analyze the response of the system under dynamic impact loading. The response was compared with that of a similar system consisting of straight circular tubes, empty and foam-filled conical tubes. Three types of such supplementary devices were included in the energy absorbing system to examine the crush behavior and energy absorption capacity when subjected to axial and oblique impact loadings. The findings were used to develop design guidelines and recommendations for the implementation of tapered tubes in energy absorbing systems. To this end, the system was conceptual in form such that it could be adopted for a variety of applications. Nevertheless, for convenience, the approach in this study is to treat the system as a demonstrator car bumper system used to...

Thin-walled structure tubes have been widely used in automotive applications as energy absorber members due to the excellent energy absorption ratio to the weights. The purpose of this study is to enhance the energy absorption of the thin-walled hexagonal tube by using different stiffeners geometries under the flexural impact. The structure has been subjected to an impact velocity of 50 km/h with a striker mass of 1500 kg at a 90-degree angle as recommended by the technical protocol section of the Insurance Institute for Highway Safety (IIHS) side-impact crash test. Besides the empty tube and the foam-filled tube, nineteen stiffeners were used in this study. A comparison between the reinforced and nonreinforced structure was made in terms of the specific energy absorption (SEA) and the crushing force efficiency (CFE). The numerical results have shown that stiffeners have improved the crashworthiness parameters when compared with the conventional empty tube. The numerical results have revealed that the introducing stiffeners to the structure have enhanced the structure performance since the stiffeners restrict the flattening of the upper side when subjected to compressive loadings and the SEA was improved for different wall thickness used. The results have shown that the H-5 stiffener was chosen as the best geometry since the SEA was increased up to 114%, the CFE was enhanced by 27% and the bending resistance was also improved.

A B S T R A C T Thin-walled cylindrical tubes are usually employed as impact energy absorbing members in automotive vehicles due to their high energy absorption capacity through progressive plastic deformation. Despite their superior impact performance, high initial peak force is the crucial problem which has potential to cause serious injury to the occupants. Hence in this study, end-capped cylindrical tubes with reduced initial peak force are proposed as energy absorbing members when subjected to axial static and impact loading conditions. The proposed tubes were fabricated by a multi-stage deep drawing process, that induces forming effects such as thickness variation, and residual stress/strain. Subsequently, numerical simulations were carried out using HyperForm 14.0® and LS-DYNA R-971® with particular attention for the transfer of forming history from deep-drawing simulations to the subsequent crash models. The axial crash performance of the end-capped tubes was also compared with open cylindrical tubes and it was found that the initial peak force of the end-capped tube is significantly reduced by 15–30% than the open cylindrical tube without compromising the energy absorption capacity. The results revealed that end-capped tubes can stabilize the deformation behavior and could be used as a good alternative to the conventional energy absorbing structures in aerospace and automotive applications respectively.

Transstellar Journals, 2019

Metallic cylindrical tubular elements have been prominent as an impact kinetic energy absorbing structures in various vehicles for their progressive deformation behaviour, long stroke and substantial energy absorbing ability. In the current research paper, systematic experiments on the crashworthiness behaviour and specific energy absorption features of deep drawn capped cylindrical aluminium tubes of different thicknesses subjected to lateral loading have been executed. Furthermore, the lateral deformation and energy absorption characteristics acquired from the quasi-static experiments were evaluated. The crashworthiness behaviour of the recommended shallow and hemispherical capped cylindrical tubes was compared to the conventional cylindrical tubes and the proposed capped cylindrical tubes absorbed more energy than the traditional cylindrical tubes. Based on the overall results obtained, it was observed that the proposed shallow and hemispherical capped cylindrical tubes showed desirable crash worthiness characteristics which is significant in the crashworthiness design of energy absorbing structures for lateral impact loading applications.

Materials Today: Proceedings, 2020

During an impact collision situation, thin-walled tubes demonstrate excellent energy absorbing capability through plastic deformation and have been widely used in various structural applications. The present article discusses about the numerical investigations on the transverse crushing behavior and energy absorption performances of various stiffened cylindrical tubular elements. Numerical models were developed with ABAQUS/CAE Ò code to predict the deformation behavior of the proposed tubes under transverse impact force. The maximum energy absorption capacity that could be attained is with a stiffened cylindrical tube of fourth type. The final outcomes revealed that stiffened cylindrical tubes are remarkable in absorbing impact energy in transverse direction.

By carrying out finite element simulation, energy absorption values of thin-walled tubes with different geometric dimensions were investigated. Square, circular, and elliptic tubes of steel and aluminum were used to compare energy absorption. The experimental results of load-displacement used for verification in the square steel tubes showed good agreement. Three-dimensional simulation was accomplished with a finite element method while the impactor collided with one side of tube and the other side was kept rigid. Square tubes for 2 specified widths with 2 different thicknesses were also compared. In addition, 2 other cross sections including circle and ellipse with the same area were studied for comparison in a loaddisplacement curve. The results show that the ellipse cross section had more energy absorption than the 2 others. Moreover, the amount of energy absorption will be greater with increasing thickness for smaller section tubes.

Publication details, including instructions for authors and subscription information: Axial crash of thin-walled circular aluminum tubes is investigated in this study. These kinds of tubes usually are used in automobile and train structures to absorb the impact energy. An explicit finite element method (FEM) is used to model and analyse the behaviour. Formulation of the energy absorption and the mean crash force in the range of variables is presented using design of experiments (DOE) and response surface method (RSM). Comparison with experimental tests has been accomplished in some results for validation. Also, comparison with the analytical aspect of this problem has been done. Mean crash force has been considered as a constraint as its value is directly related to the crash severity and occupant injury. The results show that the triggering causes a decrease in the maximum force level during crash.

Thin-Walled Structures, 2017

This article aims to present the crashworthiness performance of double section bi-tubular thin-walled structures. Double section bi-tubes were made from stainless steel sheet and consist of an outer circular cylinder and an inner tube with any one of polygonal section such as triangle, square or hexagon. By keeping the outer cylinder dimensions constant, the effect of changes in the inscribed diameter of polygonal section and the various polygonal section of the inner tube on quasi-static axial compression is studied. Bi-tubular structures with hexagonal inner tube have more energy absorption capability than the other bi-tube combinations and the single cylinder.

International Journal of Crashworthiness, 2009

Axial crash of thin-walled circular aluminum tubes is investigated in this study. These kinds of tubes usually are used in automobile and train structures to absorb the impact energy. An explicit finite element method (FEM) is used to model and analyse the behaviour. Formulation of the energy absorption and the mean crash force in the range of variables is presented using design of experiments (DOE) and response surface method (RSM). Comparison with experimental tests has been accomplished in some results for validation. Also, comparison with the analytical aspect of this problem has been done. Mean crash force has been considered as a constraint as its value is directly related to the crash severity and occupant injury. The results show that the triggering causes a decrease in the maximum force level during crash.

International journal of engineering research and technology, 2019

The crash tube is the structure connected to the bumper of an automobile or to the guard of the vehicle which absorbs the impact energy of the vehicle and gets crushed during the impact. The goal of the present work is to design the crash tube with metal and Carbon Fibre Reinforced Polymer (CFRP) and compare the crashworthiness of the composite over the metal crash tube. Since most of the automotives are already implemented the metal/alloys, hence the crash tube made of CFRP could be possible material that could be used as an alternative to the metal crash tubes. Hence in this work, the crash tubes made of metal and composites are being tested and analysed using the Finite Element Analysis (FEA) software to validate the results and the behaviour of the crash tube is observed and CFRP material would be suggested for the crash tube for the occupant and vehicle safety.

International Journal of Integrated Engineering, 2021

Structural and Multidisciplinary Optimization, 2020

This study is aimed to compare and optimise the crashing performances of an axisymmetric rectangular tube (ART) and a uniform thickness tube (UTT) under offset loading. Both ART and UTT are strengthened with diaphragms. Numerical simulations for the initial UTT with diaphragms under offset loading were firstly performed based on the experimentally validated finite element model (FEM), which illustrated that deformation process varied from stable mode to bending-sliding mode with an increase offset distance of 0-60 mm. Then, design of experiment (DOE) method was employed to determine the design domains of UTT and ART under various offset distances. Based on the results of DOE, three deformation regions were identified and parametric studies showed that the thicknesses of tubes and diaphragms had significant effects on their crashing performances. Subsequently, the irregular design domains derived from the impact condition with offset distance of 45 mm were selected to search the optimal thickness configurations of both UTT and ART. Finally, the multi-objective optimisation (MOD) was conducted by using non-dominated sorting genetic algorithm (NAGA-II) to minimise the initial peak crushing force (IPCF d) and maximise the specific energy absorption (SEA d) under multiple offset loadings. The obtained Pareto fronts showed that ART generally achieved higher IPCF d and SEA d ; however, ART outperformed UTT for both IPCF d and SEA d in certain design domains. The outcomes provide insights into the design and selection of thin-walled structures for engineering applications.

Majalah Ilmiah Pengkajian Industri

Generally, the crash box on automobile vehicles is a thin-walled structure with a square cross-section. The majority of research was carried out for a long time to find the optimum crashworthiness indicator. In this study, numerical simulations and experimental tests are used to investigate the effect of the corner radius of a square cross-section thin-walled structure on crashworthiness indicators. Quasi-static analysis with mild steel material produces the mean force (Pm) error value is less than 3% while varying the corner radius ranging from zero to 1 mm, 2 mm, and 3 mm shows energy absorption (EA) and peak force (Pmax) decreased. Keyword: Thin-walled square tube, Mild steel, Numerical simulation, Experimental test, Crashworthiness indicators.

IAEME, 2019

The deformation behaviour of cylindrical tubes have attracted the attention of researchers in recent years, due to their light weight, high energy absorption capacity and ease of fabrication. Despite their excellent crash performance, high initial peak force is a major shortcoming when they are subjected to axial impact. Though various triggering methods have been examined in the previous literature with the aim of reducing the initial peak forces, these kinds of geometrical discontinuities will decrease the stiffness of the structure and also has a drawback of reduced energy absorption capacity. Therefore, a tube configuration, which does not affect the performance of the structure in normal use, whilst it could be improving its energy absorbing characteristics and the level of deceleration pulse with delayed transfer of impact crushing force is highly desired. This article aims to propose press-formed combined geometry tubular structures which include cylindrical segment harnessed with end-caps as a frontal crash safety element in automotive vehicles.

2012

Impact is one of very important subjects which always have been considered in mechanical science. Nature of impact is such that which makes its control a hard task. Therefore it is required to present the transfer of impact to other vulnerable part of a structure, when it is necessary, one of the best method of absorbing energy of impact, is by using Thin-walled tubes these tubes collapses under impact and with absorption of energy, it prevents the damage to other parts.Purpose of recent study is to survey the deformation and energy absorption of tubes with different type of cross section (rectangular or square) and with similar volumes, height, mean cross section thickness, and material under loading with different speeds. Lateral loading of tubes are quasi-static type and beside as numerical analysis, also experimental experiences has been performed to evaluate the accuracy of the results. Results from the surveys is indicates that in a same conditions which mentioned above, sampl...