Crashworthiness Optimization a Novel Hexagonal Honeycomb Crash Box Under Crushing Test – A Numerical Study

A crash box design is developed to enhance the crash box’s abilities to absorb crash energy. Previous research has developed the crash box by adding filler material. Adding the filling material to the crash box will increase energy absorption. Aluminum honeycomb has a combination of lightweight mass and an ability to absorb crash energy. The addition of filler material to the crash box will also reduce the possibility of global bending in the crash box. The method of study is a computer simulation using ANSYS Academic software ver 18.1. This research used circular, square and hexagonal cross-section variations, which reached the same cross-sectional area design. Geometry model for the crash box and honeycomb filler is defined as crash box thickness (tc) 1.6 mm, honeycomb filler thickness (t) 0.5 mm for single layer and 1 mm for double layer and crash box length (l) 120 mm. The materials used were AA6063-T6 for crash boxes and AA3003 for honeycomb fillers. The test model consisted of two types, namely frontal load and oblique load test. The impactor velocity (v) is set to 15 m/s. The impactor and the fixed support are modeled as a rigid body, while the crash box is assumed as an elastic body. Observations were done by using the characteristics of deformation pattern and the absorption amount of produced energy due to the given loading model. Based on the deformation pattern results, it can be found that in the crash box model with square and hexagon honeycomb filler, the occurred deformation pattern was concertina, while the crash box with circular honeycomb filler was the mixed mode in the frontal load test. Regarding the oblique loads, the crash box remains to collapse the global bending on all models. Simulation results with the frontal load test model found that the crash box with circle-shaped honeycomb has the highest energy absorption while the crash box with hexagonal honeycomb filler has the highest Specific Energy Absorption (SEA). In the oblique load test, it was found that the crash box with hexagonal honeycomb filler has the highest energy absorption and SEA. By comparing the hexagonal crash box model with and without honeycomb filler, it is noted that the hexagonal crash box with honeycomb filler has higher Crash Force Efficiency

Crash box design as one of the passive safety components in a vehicle had been developed to enhance energy absorption. Initial fold on the crash box is set to facilitate folding during the crash. The aims of this study is to investigate the initial folded crash box with length to thickness ratio subjected to frontal test. The frontal test is modelled by using finite element analysis. Through computer simulation using 9 models, the obtained result was used to provide the better design of crash box. The variations in this study were length to thickness ratio of crash box with length of tube (L) = 115; 132.5; 150 mm and the thickness of tube (t) = 1.6; 2.0; 2.5 mm. The crash box material was assumed as bilinear isotropic hardening material. The velocity used in the simulations was 7.67 m/s with impact mass of 103 kg. Based on the results, it can be shown that 1st model to 8th model produce deformation pattern as concertina mode and 9th model has diamond mode. The 3rd model has the largest energy absorption with value 18.29 kJ.

Along with the elevating number of cars, accidents due to car crashes are increasing. Therefore, technology is needed to reduce the occurrence of the drivers’ injuries. Crash box is one of the potential passive safety technology which is widely observed today. Crash box is installed between bumper and chassis, aims to reduce the cassualties when the car crashes. In this article, crash box research was conducted by real experimental method through quasi-static test to evaluate the energy absorption capability of circular-shaped multi-segment crash box. Crash box material was made from aluminum A6063. The connection on each segment is a chamfer with 45 o angle. The connections between segments 1 and 2 were varied with 3 connection models, those are 1/4, 1/3 and 1/2 of the total length, i.e.120 mm. The results of the study showed that, the highest energy absorption obtained from the crash box with connection of 1/2 and the energy absorption is 5249.726 J. Crash box type of 1/4 and 1/3 exhibit energy absorption of 3886.238 J and 3106.027 J respectively. Generally, the deformation pattern on the crash box is mixed-mode (axisymmetric-diamond).

AbstrakCrash box is part of the supportingcomponents on vehicle safety, especially cars. The crash boxis designed to reduce the occurrence of driver’s injuries due to collisions. This study aimed to determine the capability of energy absorption and deformation patterns in the crash box using a three-segment circle cross-section. The research method was quasi-experimental with a simulation using Finite Element Method software. The crash box simulation carried out with a 200 kg impactor on a speed of 7.67 m/s. The independent variable in this study is the material exposure variation in the crash box using steel-aluminum-steel and aluminum-steel-aluminum. The dependent variables were energy absorption, force reaction and deformation patterns occurring in the crash box. Based on the simulation results, the values ofenergy absorption was 82452 J and force reaction was 1127700 N in the crash box of steel-aluminum-steel material. Meanwhile, the crash box material of aluminum-steel-aluminum has an energy absorption value of 236210 N, force reaction of 12432 J and a better and more stable on deformation pattern.

Crashworthiness is related to the ability of a structure to reduce the effects of a collision risk of injury to passengers and the risk of damage to vital parts of the vehicle. Geometry design of crash box is one important parameter to increase crashworthiness performance by increasing energy absorption through progressive deformation. In previous studies, circular crash box absorbed higher energy than other geometry design. Besides that, another parameter is material design. In other studies, the hybrid model absorbs more energy with a less increasing mass. Hybrid crash box combine low-density and high-strength of composite materials with aluminium materials are affordable and ductile to increase energy absorption. This study aims to develop circular hybrid crash box by variating fibre orientation angle of composite and hybrid material configuration. Crash box design is investigated by using computer simulation with ANSYS Workbench. The crash box materials used are Carbon Toray T300 – Epoxy Resin (CCE) and Aluminium Alloy 6063 (AA6063). Eight of circular hybrid crash box models subjected to axial loading with a speed of 10 m/s. The frontal loading is modelled by setting impactor with mass of 100 kg. Energy absorption and deformation pattern were observed. The results showed that the Al-Ko45 model with orientation angle [45/- 45,-45/45]5 and hybrid material configuration of composite inside has highest energy absorption of 8.24 kJ. The deformation pattern in the aluminium part is mixed of concertina at the first stage then continued by diamond pattern, The deformation composite part is dominated by local buckling with transverse shearing. The fractions or folds of composite is functions like foam-filled filling folds of aluminium deformation to initiate progressive crushing folding that can increase the crashworthiness characteristic as the energy absorption.

4D-printed deformable honeycombs exhibit stimulus-responsive shape transformations with tunable mechanical properties, which can be applied in the multifunctional scenarios of adaptive compressive and energy absorption properties. For further enhancing their mechanical performances, the gradient design approach is implemented for improving the compressive and energy absorption properties of deformable honeycomb structure. The studied honeycombs can undergo automatic deformation between hexagonal honeycomb (Structure I) and triangular honeycomb (Structure II) under external temperature stimulus. Through comparative analysis of quasi-static compression tests and finite element simulations, the energy absorption capacity of Structure I and the compressive performance of Structure II are evaluated, obtaining the optimal internal angles for each unit cell under varying wall thicknesses. The results demonstrate that the gradient configuration 8-6-8-10-8 (LBH3 in Structure I and XJH3 in Structure II) can exhibit superior mechanical performance compared to conventional uniform-thickness honeycombs. The specific energy absorption value of LBH3 is 2.65 J g−1, which is 8.16% higher than that of ID7 (uniform-thickness). Additionally, the stiffness ratio of the transformed deformable honeycomb structure XJH3 is 6.18 MPa g−1, showing a 47.14% increase in compressive resistance compared to ID17 (uniform-thickness). The gradient design results have broad application prospects for the multifunctional applications of honeycomb structures in the future.

Compression property and energy absorption capacity of 4D-printed deformable honeycomb structure

This study presents a crashworthiness evaluation of a Parallel 5-Tube Circular Multi-Segment Crash Box with a cutting die trigger, designed to promote controlled progressive folding for high-speed railway applications. The crash box integrates four primary tubes and one secondary tube in a parallel configuration, featuring multi-segment wall thickness and a die-trigger mechanism designed to initiate controlled folding from the tube’s end. The die acts as a deformation initiator, guiding the folding sequence to occur progressively, thereby improving energy dissipation and reducing peak impact forces. Two impact models, namely the Cutting Die Model (CDM) and the Flat Model (FM), were employed to investigate the combined effects of trigger mechanism, multi-segment wall thickness, and impact direction using validated finite element simulations supported by quasi-static and drop-test experiments. Finite Element Analysis (FEA) simulations using ANSYS LS-DYNA were conducted to assess key crashworthiness indicators, including maximum crushing force (Fmax), energy absorption (EA), specific energy absorption (SEA), mean crushing force (Fmean), and crushing force efficiency (CFE). Experimental validation through quasi-static and drop tests confirmed the reliability of the simulation results. The findings reveal that the CDM configuration significantly outperforms the FM model, exhibiting lower Fmax and higher EA, SEA, and CFE values. Progressive folding initiated by the die mechanism enables more stable and efficient energy dissipation. Additionally, the impact direction influences deformation behavior, with the t₁–t₂ configuration yielding superior performance. These results demonstrate the effectiveness of the proposed crash box design in meeting the stringent safety and spatial requirements of modern railway systems.

A new joining by forming process that combines lancing and shearing with sheet-bulk compression is utilized to assemble thin-walled crash boxes utilized as energy absorbers. Process design and fabrication of the new crash boxes are analyzed by finite elements and experimentation. Axial crush tests were performed to compare the overall crashworthiness performance of the new crash boxes against that of conventional crash boxes assembled by resistance spot-welding. Results show that the joining process is a good alternative to resistance spot-welding because the new crash boxes can absorb the same crushing energy, and because the new process helps to overcome typical manufacturing problems of welding.

<div class="section abstract"><div class="htmlview paragraph">Aluminium honeycombs are widely used in the field of collision buffering. Its energy-absorption capacity is determined by platform force and height, but when the height exceeds a certain value, the aluminium honeycomb will buckle as a whole rod, and its energy-absorption capacity will be lost. The buckling of long aluminium honeycomb is analyzed in this study. First, a finite element model of an aluminium honeycomb is established, and the global buckling height of the honeycomb is obtained by simulation. Then, based on the response surface method, the relationship between the global buckling height of the honeycomb and its cell side length and wall thickness is obtained. A parameter to measure the stability of the aluminium honeycomb under axial compression, namely, the height stability coefficient, is proposed, and the relationship between the coefficient and the cell side length and wall thickness under a predetermined platform stress is analysed. The results show that the wall thickness has a greater influence on the stability. This research has significance for improving the impact buffering effect of aluminium honeycombs.</div></div>

Researchers have completed many methods to increase the ability of thin tubes to absorb impact energy. Various methods are proposed covering the use of different materials, including new designs, which are expected to improve their performance. This study aims to obtain an Impact Energy Absorber (IEA), which has a low peak impact force and has better crash force efficiency (CFE), energy absorption (EA), and specific energy absorption (SEA). This study made a design change from an empty square tube to a square tube with a cell structure inside. A thin-walled box in the form of a box with a base size of 50 mm x 50 mm without a lid and a height of 150 mm with a thickness of 2 mm was used in this study. A load strikes the tube from the axial direction with a speed of 100 m/s while the other end is supported by fixed support. Deformation, impact force, and absorbed energy were recorded in all types of specimens. The results showed an increase in the reaction force between boxes that were given cells compared to empty ones. While the addition of cell variations from 1 to 2 did not experience a significant change in the impact force. The maximum deformation decreases with the number of cells, while the energy absorbed per unit length increases. The deformation pattern changes due to cells in the box because there is an obstacle when it is deformed towards the outside of the tube. The results of this study are considered in manufacturing high-speed crash boxes.

The use of bio-inspired structures in vehicles is promising. The crashworthiness performance of crash boxes inspired by honeycomb, bamboo, and horsetail structures was compared according to impact simulations. Results were compared regarding specific energy absorption (SEA), peak crushing force (PCF), and specific energy absorption to peak crushing force ratio. Single and multi-objective optimization studies were carried out with a horsetail crash box, which gave the best results. This crash box design can be used in vehicles to improve passive safety.

A finite element methodology has been developed for predicting the behaviour of honeycomb structures. Dynamic analysis of hexagonal aluminium honeycomb structures is carried out using PAM-CRASHTM, an explicit FE analysis code, and the result are verified against experimental data. Relationship between the crushing behaviour of honeycomb and simulation parameters has been established. The simulation results are also compared with theoretically predicted values. Keywords: Finite Element ModellingImpactDynamic modellingHoneycomb structuresCrushing Behaviour

A wide variety of high-performance applications require materials for which shape control is maintained under substantial stress, and that have minimal density. Bio-inspired hexagonal and square honeycomb structures and lattice materials based on repeating unit cells composed of webs or trusses, when made from materials of high elastic stiffness and low density, represent some of the lightest, stiffest and strongest materials available today. Recent advances in 3D printing and automated assembly have enabled such complicated material geometries to be fabricated at low (and declining) cost. These mechanical metamaterials have properties that are a function of their mesoscale geometry as well as their constituents, leading to combinations of properties that are unobtainable in solid materials; however, a material geometry that achieves the theoretical upper bounds for isotropic elasticity and strain energy storage (the Hashin-Shtrikman upper bounds) has yet to be identified. Here we evaluate the manner in which strain energy distributes under load in a representative selection of material geometries, to identify the morphological features associated with high elastic performance. Using finite-element models, supported by analytical methods, and a heuristic optimization scheme, we identify a material geometry that achieves the Hashin-Shtrikman upper bounds on isotropic elastic stiffness. Previous work has focused on truss networks and anisotropic honeycombs, neither of which can achieve this theoretical limit. We find that stiff but well distributed networks of plates are required to transfer loads efficiently between neighbouring members. The resulting low-density mechanical metamaterials have many advantageous properties: their mesoscale geometry can facilitate large crushing strains with high energy absorption, optical bandgaps and mechanically tunable acoustic bandgaps, high thermal insulation, buoyancy, and fluid storage and transport. Our relatively simple design can be manufactured using origami-like sheet folding and bonding methods.

The application of thin-walled tubes as energy-absorbing equipment has been recognized in various structural systems. The structure absorbs energy by converting kinetic energy to plastic deformation energy. This study will investigate the crash box with several square cross-section ratios about the ability to absorb impact energy.The specimens are made of thin aluminum tubes, 2 mm of thick, 150 mm of length, and the cross-section is a square with 50 mm x 50 mm of size. The size of the square cross-sections is varied by maintaining a fixed circumference. The steel impactor crash into the axial direction specimen by 80 m / s of velocity. The elastic deformation, plastic deformation, and the reaction force occurred due to the collision. The simulation is completed by ANSYS WORKBENCH based on the finite element method.The experiments obtained the maximum deformation, the reaction force, and plastic deformation energy. The square cross-section 50 mm × 50 mm (ratio = 1) the deformation is 49,442 mm. The greater the ratio, the greater the deformation occurs. The reaction force is also getting larger with a larger ratio. On the other hand, the energy absorbed from plastic deformation is getting smaller. It has been agreed that the cross-section ratio = 1 is the best performance of the impact energy absorption.