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

Mechanics of Advanced Materials and Structures, 2023

Over the past several decades, a noticeable amount of research efforts has been directed to minimising injuries and death to people inside a structure that is subjected to an impact loading. Thin-walled (TW) tubular components have been widely employed in energy absorbing structures to alleviate the detrimental effects of an impact loading during a collision event and thus enhance the crashworthiness performance of a structure. Comprehensive knowledge of the material properties and the structural behaviour of various TW components under various loading conditions is essential for designing an effective energy absorbing system. In this paper, based on a broad survey of the literature, a comprehensive overview of the recent developments in the area of crashworthiness performance of TW tubes is given with a special focus on the topics that emerged in the last ten years such as crashworthiness optimisation design and energy absorbing responses of unconventional TW components including multi-cells tubes, functionally graded thickness tubes and functionally graded foam filled tubes. Due to the huge number of studies that analysed and assessed the energy absorption behaviour of various TW components, this paper presents only a review of the crashworthiness behaviour of the components that can be used in vehicles structures including hollow and foam-filled TW tubes under lateral, axial, oblique and bending loading.

2010

A thin-walled cylindrical tube, when subjected to an axial load, will be folded and will absorb an impact energy. In the design of a frontal cylindrical tube for absorbing the kinetic energy during car accidents, there were a lot of theoretical and experimental researches that have de ned the characteristics of the tube during cars accidents. After studying most of these researches, it was found that the theoretical approach usually simpli ed the problem and could not be used con dently in design. Experimental approach usually faced diculty when the material was changed. In this paper, a computer simulation program joined with the response surface methodology was planned to nd the tube characteristics in axial impacts. The problem parameters were dimensional measures of an aluminium circular tube including thickness, diameter and length. The output of the work was to nd the variation of the absorbed energy and mean crash force of the tube with the parameters in the applicable automotive ranges. Also, our results were compared with some available theoretical approaches.

International Journal of Mechanics, 2020

The crash tube is one of the important parts to reduce the effects of accidents. The design of crash tube only watches the frontal crash, but oblique crash might affect the passengers. Besides, Lack of oblique-loading researches in crashworthiness becomes causes to analyze crash tubes more. This paper aims to study crashworthiness performance of octagonal-inner double tubes under off-axis oblique impact load (0°, 10°, 20°, and 30°). The tubes have been connected with two walls, top wall as moving wall and a bottom wall as rigid wall underl different load angles. The tubes were made from Aluminum Alloy and consisted of a circular-outer tube and an octagonal-inner tube. The crashworthiness parameters of absorption of specific energy (SEA), maximum collapse force (Fmax) and efficiency of crush force (CFE) were obtained for all the structures. In order to get the value of parameters, the method of finite element analysis was used. The effects of different thickness of 1 mm, 2 mm, 3 mm a...

Proceedings of 2010 Interdisciplinary Conference on Chemical, Mechanical and Materials Engineering, 2010

An optimum design for thin-walled tubular beams was presented based on their cross-sectional profiles. Optimized designs of the circular cross sectional profile for both straight and curved thinwalled tubes were obtained to optimize such tubes' crushing performance. The optimization process was carried out by using the design of experiments method (DOE) and finite element analysis (FEA). Crash behavior of both straight and curved tubes was investigated and the effects of the circular cross sections on the structures' crushing performance were analyzed. In this paper, a comparatively new but efficient FEA model, simplified model, was used for this design project. The results showed that compared to the detailed FE model, the simplified model can well be used for the product design problem while saving much more modeling labor and computer resources.

European Journal of Technic

Thin-walled structures (TWTs) are widely used in automotive and aerospace industries due to their easy formability, high energy absorption capacity, low cost, and lightweight advantages. In this study, considering the forming history, the crashworthiness of spot-welded and double-hat shaped elliptical TWT was numerically investigated under dynamic axial load, by the finite element method (FEM). In addition, a bead-shaped trigger mechanism was added to the TWT to reduce the peak crushing force. Non-uniform thickness distribution (thickening or thinning of some elements), plastic strain and work hardening may occur during forming. To investigate the effect of the forming history on crashworthiness, the sheet metal was formed by single-acting deepdrawing process and forming data were mapped to the TWT. The results showed that forming history has an effect on the crashworthiness of the tube. With deep-drawing results mapped to the tube, energy absorption decreased by 5.218% and peak crushing force decreased by 3.614%. Numerical simulations were conducted by using the nonlinear finite element codes RADIOSS/explicit.

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.