Automatic simulation and optimization of the energy absorption box driven by MO-SAC

Lightweight energy‐absorbing structures are critically needed across engineering sectors. Conventional energy‐absorbing structures have an initial peak crush force that is too high and insufficient lightweighting. This study integrates additive manufacturing with biomimetic design to develop bamboo‐inspired vascular bundle tubes(VBT). Specimens fabricated from multiple materials underwent quasi‐static axial and radial compression testing. The results demonstrate superior energy absorption performance in carbon fiber–reinforced Polyethylene Terephthalate Glycol (PETG/CF) specimens. Structural optimization incorporating bamboo‐mimetic axial vascular arrangements enhanced specific energy absorption (SEA) through improved biomimetic fidelity. Process parameter studies revealed that reducing the layer height from 200 to 100 μm simultaneously increased SEA and reduced peak crushing force (PCF) under both loading conditions. Axial loading increased SEA by 30% and reduced PCF by 15%. In contrast, radial loading resulted in a 15% increase in SEA and a 20% reduction in PCF. This work establishes a synergistic material‐structure‐process strategy for high‐performance bio‐inspired energy absorbers, advancing impact protection technology.

This study investigates the impact absorption performance of bamboo-inspired 3D-printed circular tubes in terms of infill type (grid, gyroid, honeycomb, Archimedean chords), infill ratio (10%, 20%, 30%, and 40%), wall thickness (0.8, 1.2, 1.6, and 2.0 mm), and inner diameter parameters. The structures designed using Taguchi L16 orthogonal design are printed with PLA material using FDM technology and evaluated by quasi-static compression tests. Peak crushing force (PCF), energy absorption (EA), and specific energy absorption (SEA) criteria are used to analyse crashworthiness performance. The experimental results showed that EA improves as the infill rate increases, but the gain decreases as the infill rate approaches 40% (SEA at 30% is better than that at 40%). By visualising the PCF and EA data relative to the utopia point (the lowest PCF and highest EA), GRID_T16F30D24, HCOMB_T08F30D22, and GRID_T12F20D22 are found to be the best-performing tubes. The grid and honeycomb infill types showed superiority at 20–30% infill rates and similar wall thicknesses. The Archimedean chords type performed poorly due to its tendency to fracture.

Damage 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.

This study presents a comprehensive experimental and computational investigation of the quasi-static axial compression behavior of glass fiber-reinforced polymer/ polypropylene (GFRP/PP) sandwich tubes inspired by bamboo and horsetail structures, designed for crashworthiness applications. The combination of these materials, due to their high strength-to-weight ratio, offers excellent energy absorption capabilities. To this end, firstly, single-hollow tubes were investigated numerically and experimentally. After ensuring the accuracy of the numerical results, many numerical sandwich tubes were simulated to investigate the effect of geometric parameters. Then, the numerical results such as peak crushing force (PCF) and specific energy absorption (SEA) were used as input data for learning of multi layers perceptron (MLP) algorithm network. Finally, using genetic algorithm showed the optimal specimen with t = 1.2mm, h = 80mm, and 3 GFRP sub-core tubes has the optimal crashworthiness performance. This specimen exhibits the optimal PCF (18.24 kN) and SEA (7.8J/g) values compared with the other samples. In addition, a techno-economic assessment was conducted using the Net Present Value (NPV) method to determine the long-term financial viability of replacing traditional materials with GFRP/PP. This approach is an essential step in bridging the gap between technical performance and industrial applicability. The results revealed that while GFRP/PP crash tubes offer superior weight-specific energy absorption, their economic competitiveness varies by reference material. Specifically, replacing steel and aluminum crash boxes with GFRP/PP results in positive net present values of $322.49 and $240.27 per vehicle, respectively, highlighting clear financial and environmental benefits.

Thin-walled structures are extensively utilized in construction because of their lightweight nature and excellent energy absorption efficiency, especially under dynamic loads. Improving the energy-absorbing performance of thin-walled structures by inspiring natural multi-cell designs is a sufficient approach. This paper investigates the energy-absorbing characteristics of variable novel cross-section designs of thin-walled structures subjected to oblique impact loading. Straight and tapered types with seven cross-sectional designs of novel thin-walled structures were studied. The nonlinear ABAQUS/Explicit software 6.13 version was implemented to analyze the crashworthiness behaviors for the proposed variable cross-section designs under different loading angles. The crushing behaviors of the proposed thin-walled structures were examined for various wall thicknesses of 0.5 mm, 1.5 mm, and 2.5 mm and impact loading angles of 0°, 15°, 30°, and 45°. It was determined that the energy-absorbing characteristics of novel thin-walled structures can be efficiently controlled by varying two geometries and seven cross-section designs. A multi-criteria decision-making method (MCDM) using a complex proportional assessment method (COPRAS) was performed to select the optimum thin-walled structures with cross-section designs. It was shown that a tapered square thin-walled structure with 2.5 mm thickness had the best crashworthiness performances with energy absorption (EA) of 11.01 kJ and specific energy absorption (SEA) of 20.32 kJ/kg under a 30° impact angle. Moreover, the results indicated that the EA of the thin-walled structure decreased with the increase in the impact loading angle. In addition, with the increase in the impact loading angle, the peak crushing force (PCF) decreased and reflected the reduction in energy absorbed at a larger angle. The MCDM method in conjunction with the COPRAS method is proposed, it provides valuable insights for safer and more resilient building construction.

This paper aims at optimising the crashworthiness capabilities of hybrid S-shaped rails of an automotive body under oblique impact loading. In the optimisation process, geometrical parameters, material types and the length ratios of aluminium part to the whole length are taken as design variables. Kriging metamodel techniques are performed to predict the crashworthiness criteria of specific energy absorption (SEA) and peak crushing force (PCF). In the following multi-objective optimisation design (MOD), non-dominated sorting genetic algorithm (NSGA-II) is adopted to obtain maximum SEA capacity and minimum PCF of hybrid S-shaped rails. It is found that the optimum design for a specific load angle does not necessarily guarantee the best solution when the load angle changes. More importantly, the change of weighting factor for each load angle affects the Pareto front of such MOD considerably, and thus selecting proper weights is of great importance in the crashworthiness design of hybrid S-shaped rails.

Crashworthiness design of functionally graded foam-filled multi-cell thin-walled structures

Crashworthiness analysis of foam filled star shape polygon of thin-walled structure

A bio-inspired multi-layer sandwich structure (BS) based on the microstructure of Odontodactylus scyllarus dactyl club was developed. Crashworthiness of BS variants (BSU, BSI, BSD) with varying thicknesses (t) and height-length ratios (η) was analyzed via LS-Dyna FE simulations, validated experimentally (with an average relative error of 1.98%). Evaluations using peak crush force (PCF), specific energy absorption (SEA), and crush force efficiency (CFE) revealed BSI and BSU outperformed BSD at t = 0.3 mm and t = 0.5 mm. Multi-objective optimization via Kriging models and MOPSO algorithm optimized t and η (η 1, η 2, η3) across four weight cases. The optimal design balancing all criteria was t = 0.33 mm, η 1 = 0.77, η 2 = 0.96, η 3 = 1.01. This study can provide a reference for the design and optimisation of multi-layer sandwich structures.

Crashworthiness design of novel hierarchical hexagonal columns

This research investigates the crashworthiness behavior of bio-inspired, hybrid aluminum and polypropylene (Al/PP) sandwich tubes, as well as single Al and PP hollow tubes, under quasi-static lateral loading both experimentally and numerically. It examines the effects of material permutation of single tubes and variations in inner tube diameters on energy absorption behavior by validating a Finite Element (FE) model against experimental results using LS-DYNA software for simulations. The simulation process accurately predicted the folding mechanism and crashworthiness parameters. The study then conducts a comprehensive FE parametric analysis, performing many simulations with variations in inner tube diameter and thickness, using a full-factorial design approach. To evaluate the tubes’ energy absorption, the research integrates the findings into machine learning algorithms. Specifically, Multilayer Perceptron models trained with the Bayesian-Regularization training algorithm are used to predict the specific energy absorption (SEA) and peak crushing force (PCF) to refine geometric parameters. The objective is to minimize PCF while maximizing SEA. Optimization using the non-dominated sorting genetic algorithm II (NSGA-II) identified an APA sandwich tube configuration with 1.5 mm thickness, 35 mm diameter and 8 core tubes as the optimal design for crash resistance.

To solve the problem of high peak force and large load fluctuation of combined energy-absorbing structures, a coordinated design strategy based on staggered compensation of load curves was proposed. First, an energy-absorbing unit of metal thin-walled tapered square tube was designed, and its crashworthiness was verified by experiment and simulation, and the peak force was reduced by introducing a groove inducing structure. Then, a combined structure with multi-level energy-absorbing units was proposed through layout arrangement and dimensional design. The parameter analysis was performed using a validated surrogate model. It is found that the thickness of the outer tube of the energy-absorbing units has a significant effect on peak crushing force (PCF), crushing force uniformity (CFU) and specific energy absorption (SEA). To improve the crashworthiness of the combined structure, a multi-objective optimisation was applied to achieve the maximum CFU and SEA values, and weight factors were introduced to select design schemes. The results show that the optimised combined structure reduces PCF by 44.48% and increases CFU by 50.78%, while improving the SEA.

Influence of strain rate effect on energy absorption characteristics of bio-inspired honeycomb column thin-walled structure under impact loading

Lattice structures and thin-walled tubes are two types of energy-absorbers widely studied and applied in engineering practice. In this study, a new type of lattice-structure filled thin-walled tube (LFT) was proposed by combining these two energy absorbers and designed via a new explainable data mining method. In this new type of LFT, a BCC-Z (Body- centred cubic unit cell with vertical struts) lattice structure was filled into a square thin-walled tube. Then, the new LFT was parameterized by five design variables, that is, the number of layers in the longitudinal direction (n), number of cells in the transverse direction (m), rod diameter (d), tube thickness (t) and height difference between tube and lattice structures (h). Using Latin hypercubic sampling algorithm, 150 design cases were generated. Numerical models were then developed to simulate their crush behavior, and the simulation dataset was used for data mining. The results showed that (1) Filling the BBC-Z lattice structure into a thin-walled tube can significantly improve the energy absorption (EA) capacity of the structure. (2) SEA (Specific Energy Absorption) of LFT significantly increased by increasing the rod diameter d, number of cells in the transverse direction m and number of layers in longitudinal direction n. (3) The decision trees generated in the data mining process indicated that the rod diameter d of the lattice structure is the key design variable that has most significant impact on EA, followed by m and n. (4) The design rules to build LFTs with high EA efficiency (SEA ≥ 16 kJ/kg and CFE (Crush Force Efficiency)≥45%), high total EA (SEA ≥ 16 kJ/kg and EA ≥ 6 kJ) and lightweight (SEA ≥ 16 kJ/kg and Mass ≤ 0.45 kg) were obtained from decision trees. The ideal configurations of LFT corresponding to these three objectives are: d > 2 mm, n > 2 and m > 3 for high EA efficiency; d > 2 mm, n > 2 and m > 3 for high total EA; and d > 2 mm, n > 2, m ≤ 4 and t ≤ 1.7 mm for lightweight.

In this work, the impact of temperature on the crushing performance of multi-walled tube (MWT) were investigated using a combined experimental, theoretical and numerical method. The MWT was fabricated using extrusion technology, and the temperature-dependent axial crushing experiment was performed on a hydraulic testing machine. The results show that the peak crushing force (PCF), the mean force (Pm) and the specific energy absorption (SEA) decreased near-linearly by 21.7%, 30.7% and 30.7% as the temperature increased from 25 °C to 250 °C, while the crushing load efficiency (CLE) was insensitive to temperature. The average forces obtained via numerical prediction, theoretical analysis and experimental testing were basically consistent. The numerical results indicate that varied temperature alters the number of dominant wavelets and the relative lateral deflections of MWT. In addition, compared with the competitive structures, the energy absorption property of MWT is excellent at high temperatures.