A numerical study on energy absorption capability of lateral corrugated composite tube under axial crushing

Abstract: The main purpose of this work is to investigate the yield criterion and dynamic response of fully clamped slender rectangular sandwich tubes with metal foam core struck by a low-velocity heavy mass...

Abstract: The aim of this study is to investigate the energy-absorbing behaviors of hybrid composite tubes under static load and their multi-objective optimization. For this purpose, energy-absorbing behaviors of single (S_Al, S_St, S_C) and double (D_Al-St, D_Al-C, D_St-C) tubes made of Al 6063, St 52, and CFRP are numerically investigated. Static compression tests are performed for single and double tubes and modeled with the finite element method . Besides, Foam 1 (500 kg / m 3), Foam 2 (750 kg / m3) and Foam 3 (1000 kg / m3 ) aluminum foam fillers with different densities are used in single and double tubes. In foam-filled single and double tubes, wall thicknesses were (1–4 mm) and foam densities were (500–1500 kg / m 3 ); multi-objective optimization studies (MOO) were carried out in order to obtain the lowest peak force, highest specific energy absorption (SEA), and crash force efficiency (CFE). As a result of the optimization studies, it has been observed that it is possible to increase the absorbed energy values without sacrificing SEA values in double tubes.

Abstract: In order to meet the increasing application requirements with regards to structural impact resistance in industries such as mining, construction, aerospace engineering, and disaster relief and mitigation, this paper designs a variant truss beam structure with a large shrinkage ratio and high impact resistance. Based on the principle of the curved trajectory of scissor mechanisms, this paper conducts a finite element simulation analysis of the impact load on the truss beam structure, a theoretical analysis of the impact response and a relevant prototype bench-top experiment, completing a full study on the impact resistance mechanism of the designed variant truss beam structure under the impact load. In the paper, the buffer effect of the external load impact on the variant truss beam structure is analyzed from the perspective of the energy change of elastic–plastic deformation. This paper proposes an optimization strategy for the variant truss beam structure with the energy absorption rate as the optimization index through extensive analysis of the parameter response surfaces. The strategy integrates analyses on the response characteristic analysis of various configuration materials to obtain an optimal combination of component parameters that ensures that the strength of the truss beam structure meets set requirements. The strategy provides a feasible method with which to verify the effectiveness and impact resistance of a variant truss structure design.

Abstract: The finite element (FE) simulation of industrial size composite structures under crush loading is a challenging task. Currently, the vast majority of these simulations employ non-physical “tweaking” parameters that are undesirable and limit the confidence in their predictive capabilities. This paper investigates three different material models based on continuum damage mechanics (CDM) within two commercial FE software packages, ABAQUS/EXPLICIT and LS-DYNA, to identify FE-code and material model-independent capabilities, limitations and challenges of physically-based axial crush simulation of composite structures without the use of non-physical parameters for model calibration. In particular, we show that the commonly applied crack band scaling in CDM-based material models is not suitable for the simulation of axial crushing where the dominant mode of failure is fragmentation.

Abstract: This paper reviews the common shapes of collapsible energy absorbers and the different modes of deformation of the most common ones. Common shapes include circular tubes, square tubes, frusta, struts, honeycombs, and sandwich plates. Common modes of deformation for circular tubes include axial crushing, lateral indentation, lateral flattening, inversion and splitting. Non-collapsible systems, such as lead extrusions or tube expansions, are considered to be beyond the scope of this review.

Abstract: Carbon fibre composites have shown to be able to perform extremely well in the case of a crash and are being used to manufacture dedicated energy-absorbing components, both in the motor sport world and in constructions of aerospace engineering. While in metallic structures the energy absorption is achieved by plastic deformation, in composite ones it relies on the material diffuse fracture. The design of composite parts should provide stable, regular and controlled dissipation of kinetic energy in order to keep the deceleration level as least as possible. That is possible only after detailed analytical, experimental and numerical analysis of the structural crashworthiness. This paper is presenting the steps to follow in order to design specific lightweight impact attenuators. Only after having characterised the composite material to use, it is possible to model and realise simple CFRP tubular structures through mathematical formulation and explicit FE code LS-DYNA. Also, experimental dynamic tests are performed by use of a drop weight test machine. Achieving a good agreement of the results in previously mentioned analyses, follows to the design of impact attenuator with a more complex geometry, as a composite nose cone of the Formula SAE racing car. In particular, the quasi-static test is performed and reported together with numerical simulation of dynamic stroke. In order to initialize the collapse in a stable way, the design of the composite impact attenuator has been completed with a trigger which is consisted of a very simple smoothing (progressive reduction) of the wall thickness. Initial requirements were set in accordance with the 2008 Formula SAE rules and they were satisfied with the final configuration both in experimental and numerical crash analysis.

Abstract: The present paper describes an experimental and numerical investigation on energy absorbers for Formula One side impact and steering column impact. The crash tests are performed measuring the load-shortening diagram and the energy absorbed by the structure. A finite element model is then developed using the non-linear, explicit dynamic code LS-DYNA. To set up the numerical model, tubes crushing testing are conducted to determine the material failure modes and to characterise them with LS-DYNA. The results presented in this study show that the composite structural components of the investigated Formula One racing car possess high value of specific absorbed energy and crash load efficiency around 1.1. The finite element simulations accurately predict the overall shape, magnitude and pulse duration in all the types of impact as well as the deformation and failure of the structures. Comparing the numerical data of the specific absorbed energy to the experimental results, the differences are around 10%.

Abstract: In the simulation works described in this paper the LS-DYNA3D explicit finite element code is used to investigate the compressive properties and crushing response of square carbon FRP (fibre reinforced plastic) tubes subjected to static axial compression and impact testing. A series of models was created to simulate some of the static and dynamic tests performed in the National Technical University of Athens using CFRP tubes featured by the same material combination (woven fabric in thermosetting epoxy resin) and external cross-section dimensions, but different length, wall thickness, laminate stacking sequence and fibre volume content. Simulation works focused on modelling the three modes of collapse (i.e. progressive end-crushing with tube wall laminate splaying, local tube-wall buckling and mid-length collapse) observed in the series of static and dynamic compression tests. Satisfactory level of agreement between calculations and test results was obtained regarding the main crushing characteristics of the tested CFRP tubes—such as peak compressive load and crash energy absorption and the overall crushing response—as the finite element models were refined several times in order to obtain optimum results.