Crashworthiness Analysis Research Articles

Machine learning enhanced optimisation of crash box design for crashworthiness analysis

AbstractThe primary goal of the current study is to optimise crash box designs for automobiles. Machine learning (ML) techniques are used to build an intelligent and reliable ML framework. With the help of this framework, the crash box design can be optimised for crashworthiness analysis. The optimisation of the crash box design is resource‐intensive due to its intricate geometric design, use of a variety of materials, and extensive use of dynamic simulations to determine the ideal structural parameters through simulations. A reinforcement learning‐based (RL) optimization technique is developed for this reason. The crash box is built with nonlinear first‐order shear deformation shell elements to provide the necessary simulation data, and nonlinear elastoplastic material is used to model the dynamic impact process. The RL agents are tuned using finite element (FE) simulations and synthetic data generated by a generative adversarial network (GAN) to optimise and select the optimal model parameters for vehicle crashworthiness analysis. To estimate the correct model parameter required to fulfil specified crashworthiness metrics, the RL agent learns and optimises automatically. This method is effective in terms of resources and could be helpful in the early stages of vehicle development.

Crashworthiness analysis of the biomimetic lotus root lattice structure

Crashworthiness analysis of the biomimetic lotus root lattice structure

The analysis of crashworthiness and dissipation mechanism of novel floating composite honeycomb structure against ship-OWT collision

High-energy ship collisions can cause catastrophic damage to offshore wind turbines (OWTs). This paper proposes a novel floating composite honeycomb anti-collision structure to reduce damage caused by ship-OWT high-energy collisions. The typical collision scenarios are conducted to investigate the damage analysis of anti-collision structures and the dynamic response of OWT with and without anti-collision structures via ABAQUS/Explicit. Regarding the configuration of the composite honeycomb anti-collision structure, the elastic-plastic theory of sandwich beams is proposed and an elastic-plastic analysis on the sandwich wall honeycomb core structure is performed to investigate its dissipation mechanism and obtain homogeneous material parameters of the cells. The homogenization parameters are incorporated into the ship-OWT anti-collision analysis to evaluate their applicability. The collision simulation results demonstrate that the proposed anti-collision structure is capable of effectively absorbing 80% of the initial kinetic energy and significantly reducing the dynamic response of the structure. In elastic-plastic analysis, the proposed elastic-plastic theory of sandwich beams effectively addresses the elastic-plastic behavior of honeycomb with sandwich walls, yielding results consistent with the stress-strain curve obtained from finite element analysis (FEA). In the coupled analysis, the obtained parameters of the homogenized honeycomb validate its effectiveness and enhance computational efficiency. Valuable results are given for the engineering design.

Crashworthiness analysis and optimization of a novel “cake-cutting” multi-cell tube

Increasing the number of corners can effectively increase the energy absorption of thin-walled tubes. To obtain a thin-walled tube with better energy absorption performance, a novel type of multi-cell thin-walled tube is formed by adding three rib plates, imitating the way of cutting a cake. The rib plates can divide the circular tube into multi-cell tubes with different numbers of multi-cells, and numerical simulations are conducted for the crashworthiness analysis under the axial and oblique impact loadings. The results show that the deformation mode under axial impact is more stable when the number of "cakes" is maximum, and the specific energy absorption is increased by 46% compared with the traditional circular thin-walled tube. Then, a multi-objective optimization framework is employed to find the cutting configuration for better crashworthiness performance. It is found that the optimal multi-cell tube inspired by the “cake-cutting” method can increase energy absorption by 17.4% compared with the original tube. This cake-cutting method provides an innovative designing idea of a thin-walled structure for energy absorption.

Multi-objective robust optimization of foam-filled double-hexagonal crash box using Taguchi-grey relational analysis

In this paper, a novel thin-walled double-hexagonal crash box is first proposed and then multi-objective robust optimized for better overall crashworthiness under multi-angle impact loading, using a proposed hybrid method combining aluminum foam-filling and Taguchi-grey relational analysis (GRA). Specifically, the finite element (FE) models of the regularly-shaped double-hexagonal column (DHC) extracted from original irregularly-shaped crash box under multi-angle impact loading, including hollow (H-DHC) and foam-filled (F-DHC), are first built and validated by experiments. On this basis, a comprehensive crashworthiness comparison is conducted to explore relative merits of F-DHC over original H-DHC under multi-angle impact loading. After that, the F-DHC is multi-objective robust optimized for maximizing overall specific energy absorption (SEAθ) and minimizing overall initial peak crushing force (IPCF0) simultaneously under multi-angle impact loading, using a hybrid method of Taguchi-GRA. At last, a bumper-crash box integrated crashworthiness analysis under multi-angle impact loading is executed to further verify the optimization. The optimal F-DHC and the optimized crash box within the optimal F-DHC demonstrate evident improvement of crashworthiness compared to their respective initial designs, indicating aluminum foam-filling combined with Taguchi-GRA could be an effective approach for multi-objective robust optimization of the novel crash box and other similar vehicle structures.

Crashworthiness analysis and multi‐objective optimization of Al/CFRP hybrid tube with initial damage under transverse impact

AbstractDamage can cause uncontrollable changes during the service of a structure, leading to a reduction in mechanical properties and ultimately to structural failure. This paper presents an experimental and numerical study of the crashworthiness of thin‐walled Al/CFRP hybrid tubes with pre‐existing transverse compression damage under transverse impact loading. Experiments shows that initial damage has a more limited effect on the energy absorption capacity of hybrid tubes under impact loading, but has a greater effect on their deformation pattern and the evolution of damage. After impact, cracks on the surface of the damaged tube propagate into multiple, discontinuous cracks with a total length similar to the length of the tube. Conversely, only short cracks are generated on the intact tube. Subsequent finite element simulations demonstrate the validity and accuracy of a coupled multi‐loads model and explore the effect of different structural parameters (winding angle and number of CFRP layers, and thickness of Al tube) on the crashworthiness of the hybrid tubes. Finally, a multi‐objective snake optimizer algorithm (MOSO) was used to obtain an optimal hybrid tube structure for multiple loading conditions in order to minimize the effect of initial damage on the crashworthiness of the hybrid tube. In comparison to the simulation outcomes for the original structure, the peak crushing force (PCF) decreased by 28.46%, whereas the specific energy absorption (SEA) increased by 44.59%.Highlight The effect of pre‐existing damage on the crashworthiness and deformation pattern of hybrid tube structures is investigated by means of experimental and numerical simulations. A multi‐step finite element model was developed using the restart method to realize the crashworthiness analysis of the hybrid tube under multiple load coupling conditions. The prediction accuracy of four surrogate models for the crashworthiness of hybrid tubes is compared and analyzed. The multi‐objective snake optimizer algorithm (MOSO) is proposed to obtain the optimum hybrid tube structure for multiple loading conditions.

Crashworthiness analysis and structural optimization of shrink tube under interference condition

This paper aims to study the crashworthiness of shrink tubes for rail vehicles under axial impact loading. A theoretical model of shrink tube for platform force prediction under interference fit conditions was proposed. The trolley crash test was used to experimentally study the structural energy absorption and characteristics during collision, and a corresponding finite element model was constructed and validated. The finite element model validated the accuracy of the theoretical model. The influence of structural parameters on the crashworthiness of shrink tube under interference conditions was then studied. Structural design variables, including the magnitude of interference (int_pre), thickness (T), long right-angle edge (tri_x) and short right-angle edge (tri_z) were sampled using a full factorial and a Latin hypercube design method. Based on the above samples, the moving least squares method (MLSM) was used to construct an approximate model of peak force (Fmax), specific energy absorption (SEA), and platform force (Fplt). The main effects analysis illustrated that the tri_z had the most significant effects on the peak force, specific energy absorption and platform force. To minimize Fmax and maximize SEA, the global response surface method (GRSM) was employed for parameter optimization. Finally, the optimized configurations were obtained with int_pre=0.067mm, T=10.003mm, tri_x=21.485mm, and tri_z=6.101mm. Compared to the initial design, the SEA value was increased by 16.41 %, while the Fmax value was decreased by 2.21%. The error of platform force derived from the optimal solution and theoretical prediction was 3.62%, which verified that the theoretical prediction model was credible within an acceptable range.

Numerical Analysis of Crashworthiness on Electric Vehicle’s Battery Case with Auxetic Structure

Due to the reduction in pollutant emissions, the number of electric vehicles has experienced rapid growth in worldwide traffic. Vehicles equipped with batteries represent a greater danger of explosion and fire in the case of traffic accidents, which is why new protective systems and devices have been designed to improve impact safety. Through their design and construction, auxetic structures can ensure the efficient dissipation of impact energy, reducing the risk of battery damage and maintaining the safety of vehicle occupants. In this paper, we analyze the crashworthiness performance of a battery case equipped with an energy absorber with a particular shape based on a re-entrant auxetic model. Simulations were performed at a velocity of 10 m/s and applied to the battery case with a rigid impact pole, a configuration justified by most accidents occurring at a low velocity. The results highlight that by using auxetic structures in the construction of the battery case, the impact can be mitigated by the improved energy absorber placed around the battery case, which leads to a decrease in the number of damaged cells by up to 35.2%. In addition, the mass of the improved energy absorbers is lower than that of the base structure.

Kelvin-Voigt lumped parameter models for approximation of the Power-law Euler-Bernoulli beams

The purpose of this research is to initiate an investigation of the nonlinear material strain-rate damping effects on the amplitude and frequencies of some Euler-Bernoulli Beams. It is well known that the dynamic behaviors of most heat-treated metals can be modelled by using the power-law strain-rate dependent constitutive equations. Lumped parameter models for approximations of dynamic vibration of the power-law Euler-Bernoulli Beam subject to power-law strain-rate damping and concentrated loads are formulated. Analytic formulas of the lumped parameters, including effective the train-rate damping, are derived. The lumped-parameters are also evaluated numerically by a low-order Galerkin Method to validate and compare the lumped parameter model with another numerical model. Numerical examples made of some heat-treated aluminum and stainless-steel alloys are presented to illustrate the implications of the aforementioned lumped-parameter models on the dynamics of the beams. The results obtained in this work cover with the classical results in the literature for linear the materials as special cases. The novel lumped parameter models can provide useful insights for crashworthiness analysis of structures of heat treated metals and thermal plastics.

Crashworthiness analysis of a novel bioinspired hexagonal honeycomb under out-of-plane crushing

In this paper, a novel bioinspired hexagonal honeycomb (NBHH) is proposed. Different from the conventional honeycomb (CH), the core wall of the NBHH has a saw-tooth corrugated shape. Firstly, LS-DYNA R11.0 is used to construct a finite element model and conduct experimental verification; then, a comparative analysis is carried out with the CH and the bionic honeycomb sandwich panel (BHSP) with sinusoidal curves, and the proposed NBHH exhibits excellent energy absorption capability under dynamic impact. In particular, compared with the CH and the BHSP with the same wall thickness, the specific energy absorption of the NBHH is 58.60% higher than that of the CH. Compared with the BHSP, the specific energy absorption of the NBHH has increased by 7.23%. Finally, parametric research is carried out on the NBHH.

Crashworthiness analysis and multi-objective optimization of spatial lattice structure under dynamic compression

A spatial lattice structure is proposed to improve the structural crashworthiness and energy absorption. First, a single-cell structure is proposed via a bionic honeycomb, and then the single-cell structure is arrayed to form a spatial lattice structure. The finite element model of the spatial lattice structure for crashworthiness analysis is established. The theoretical model of the plateau stress of the lattice structure under compressive conditions is derived, and its accuracy is verified by the corresponding finite element analysis. After that, the effect of geometrical parameters of single-cell structure on crashworthiness is analyzed. Then, geometrical parameters of single-cell structure and number of single-cell in the X, Y, and Z directions are used as design variables, the mass, and overall size are used as constraints, and specific energy absorption and collision peak force are used as optimization objectives. The multi-objective crashworthiness optimization of spatial lattice structure is carried out, and the optimal lattice structure design is determined via the gray relational analysis coupling entropy weight method. The validity of the finite element model and optimal design is verified by the drop weight impact test. The crashworthiness optimization of spatial lattice structures has important guiding significance for the design of energy-absorbing structures.

Crashworthiness analysis and optimization of multi-functional gradient foam-aluminum filled hierarchical thin-walled structures

The combination of metallic thin-walled structures and foam aluminum with lightweight characteristics and high energy absorption can further improve the crashworthiness of hollow homogenized structures. A novel tri-functional gradient (TFG) hierarchical thin-walled structure to simultaneously improve lightweight and crashworthiness is proposed, which is an aluminum-foam-filled hierarchical structure with functional gradient strength and thickness properties. Three characterized indices including the thickness index m, density index n, and strength index p are introduced to analyze the crashworthiness of TFG structure. The experimental results show that the crashworthiness of the TFG structure is superior to the uniform functional gradient (UFG) structure. The peak crushing force (PCF) and specific energy absorption (SEA) of TFG structure can reach 133kN and 19.903 kJ/kg, SEA is improved by 13.71% and PCF is reduced by 40.36%. Besides, the thickness and strength of the external tube is the primary factor affecting the PCF. The crashworthiness of the TFG structure is highly dependent on the synergistic combination of three gradient indices. When the combination of (m, n, p) is (0.25, 0.25, 0.25), the maximum SEA is 21.206 kJ/kg. The thickness and strength indices m, n have a large effect on SEA and PCF, yet the density index n has barely any effect on SEA and PCF. Furthermore, the non-dominated sorting genetic algorithm II (NSGA-II) is employed to build the optimal Pareto frontier aim at this TFG structure to realize a coupled material-function-structure multi-objective optimal design.

Crashworthiness Analysis of Vehicle Crash-Box Filled with Aluminium Foam

Lightweight, robust, and anti-rust properties of aluminium foam might be a solution for reducing the effect of traffic accidents and for minimum fuel consumption. This research investigated the crashworthiness of vehicle crash-box filled with aluminum foam by varying its cross-sectional structure and its loading angle such as 0°, 10°, 20°, 30°. The variations consisted of structures for example single wall foam filled and double wall foam filled. The material used to construct the wall was Aluminum Alloy 2024 and Aluminium foam. The finite element model using Abaqus CAE Software was operated for both designing the crash-box and analyzing its crashworthiness. Some parameters were determined To obtain the best crash-box design, the finite element analysis was carried on total energy absorption, specific energy absorption, maximum load, average load, and crush-force efficiency. Double wall foam filled crash-box was shown to have better energy absorption ability and this structure of crush box is considered fpr vehicle structure in future.

Crashworthiness Analysis of Thin-Walled Square Columns with a Hole Trigger.

Thin-walled structures dynamically loaded with an axial force are the subject of this study. The structures work as passive energy absorbers by progressive harmonic crushing. The absorbers were made of AA-6063-T6 aluminum alloy and subjected to both numerical and experimental tests. Experimental tests were performed on an INSTRON 9350 HES bench, while numerical analyses were performed using Abaqus software. The energy absorbers tested had crush initiators in the form of drilled holes. The variable parameters were the number of holes and their diameter. The holes were located in a line 30 mm away from the base. This study shows a significant effect of the hole diameter on the values of the stroke efficiency indicator and mean crushing force.

Experimental investigation and crashworthiness analysis of 3D printed carbon PA automobile bumper to improve energy absorption by using LS-DYNA

This research work aimed to enhance the crashworthiness of the existing automobile bumper to minimize crash injuries. As per the simulation results the weight of the carbon polyamide-based bumper is reduced in comparison with the existing steel bumper by 9.7 kg or 47.5%, with this reduction in weight 38% increase in fuel economy has been estimated. The energy absorption capability of carbon polyamide bumper is improved from the existing steel and aluminum bumper by 11.15% and 16.3% respectively and with this modification, the impact force is reduced from the existing steel bumper, which has 4.87 kN and aluminum alloy bumper, which has 4.10–1.86 kN. The crashworthiness parameter result analysis showed that the corrugated bumper geometry had a structural energy absorption (SEA), total energy absorption (TEA), and crush force efficiency (CFE) of 103.28 J/kg, 911 J, and 77.99%, which is higher than the hallow bumper geometry of 102.4 J/kg, 847 J, and 65.83% respectively. In addition to that, as the thickness of carbon polyamide bumper reduced from 4 mm to 3.5, 3, and 2.5 mm, deformation increased with a small rate from 13.5 mm to 16.7, 18.52, and 22.04 mm.

Crashworthiness analysis of hexagonal hierarchical gradient tubes with axial variable thickness inspired by tree fractal structure

Inspired by the tree fractal structure, a novel hexagonal hierarchical gradient tube with axial variable thickness (HHGAVT) is proposed and its crashworthiness performances are systematically investigated. Results show that when the axial variation coefficient of wall thickness k > 0, the peak crushing force (PCF) of HHGAVT will significantly decrease meanwhile the energy absorption maintains at a high level compared with the referenced structures under the same mass. When k > 0, the PCF and CFE of HHGAVT have absolute advantage compared with the uniform wall thickness tube. The crashworthiness performance can further increase by rational designing the distance factor δ.

Correction to: Comparative Analysis of Crashworthiness of Empty and Hybrid Mild Steel High Density Polyethylene Cylindrical Tubes Under High Axial Impact

Correction to: Comparative Analysis of Crashworthiness of Empty and Hybrid Mild Steel High Density Polyethylene Cylindrical Tubes Under High Axial Impact

Crashworthiness analysis and uncertainty optimization of novel multi-wall tube

Multi-wall tube has excellent crashworthiness therefore is widely used in energy absorption. The crashworthiness of multi-wall tube is not only related to shape but also materials. However, the specific value of some material parameters cannot be determined, instead, only interval can be confirmed. In this work, a novel multi-wall tube (NMT) that is composed of octagon and nested quadrilateral was designed and an interval uncertainty optimization method was proposed to improve the crashworthiness. Firstly, the crashworthiness of the NMT, octagonal multi-wall tube (OMT) and square double-wall tube (SDT) under axial load was compared and analyzed by experimental and numerical simulation. It indicated that NMT has obvious energy absorption advantages and good progressive deformation mode. Moreover, the energy absorption of NMT structure is more sensitive to wall thickness than wall spacing ratio and inner wall length. Then, based on the theory of simplified super folding element (SSFE), the theoretical model of NMT was proposed. The theoretical analysis is consistent with the simulation results. Finally, according to the interval number theory, the uncertain interval optimization problem was transformed into deterministic optimization and reliability analysis. Non-dominated sorting genetic algorithm II (NSGA-II) was used to seek superior crashworthiness of NMT. When considering interval uncertainty in optimization, the reliability of crashworthiness of the NMT can be further improved. The research results provide a good guidance and theoretical support for crashworthiness optimization design.

Failure criteria in crashworthiness analysis of ship collision and grounding using FEA: Milestone and development

This study presents reviews of the failure criteria to capture the resulting response due to the catastrophe of ship collision and grounding using the finite element. Researchers have introduced several failure criteria, for instance, the DNV RP-C204 criterion, Germanischer Lloyd criterion, Peschmann, RiceTracey and Cockcroft-Latham (RTCL), Bressan-Williams-Hill (BWH) instability criterion, and Liu criterion. As in the mathematical formula, each criterion has a difference. The choice of failure criteria will depend on the simulation's specific requirements and the analysis's goals. Liu's criterion can be used to evaluate the failure of materials in ship collision simulations, for example, when large element sizes (i.e., 20 mm) are considered in the simulation.

Crashworthiness Analysis to Evaluate the Performance of TDM-Shielded Street Poles Using FEA

The mitigation of the risks of passenger injuries when a vehicle is involved in a collision with a street pole shielded with a layer of tire-derived material (TDM) was assessed. This can effectively absorb a fraction of the total energy from a speeding vehicle. Since such tests are expensive to conduct experimentally, the study relies on using the Abaqus/Explicit FEA solver to accurately calculate the non-linear nature of this scenario. Two categories of this scenario were evaluated to understand the effect a shielded street pole has on the vehicle—and the total absorbed energies during frontal and corner collisions, which are typically the most common categories of such accidents to happen. Results show that at lower speeds, these reinforcements are least effective in absorbing some of the kinetic energy applied by the vehicle, with about 5% of the energy absorbed by the reinforcement. At higher speeds, however, the results show that the TDM reinforcement absorbs about 28% of kinetic energy, which can reduce injury of the vehicle occupants, as well as decrease the damage on poles. Results for this simulation also show that there is a critical thickness of TDM that can absorb these kinetic energies, after which further thicknesses results in energies being applied back to the vehicle, therefore negating any purpose to further increase TDM thicknesses.