Energy absorption of additively manufactured functionally bi-graded thickness honeycombs subjected to axial loads

Crush initiators are used to improve the energy absorption and reduce the peak crush load at the time of the initial accident. This study aims to determine the effect of crush initiators on thin-walled square tube of local product which is applied on the front rail Electric Cars University of Indonesia under the quasi static axial loads. Crush initiator was designed in the form of two parallel holes with a diameter of 6.5 mm at a distance of 20 mm from the surface of the tube on each side. Analysis was done by comparing the experimental result with the result of numerical analysis by using finite element method of ANSYS. The result showed the significant effect from the crush initiators on decreasing the peak crush load and increasing the energy absorption and showed a similar pattern between the experimental and numerical computation result.

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Multi-Objective Optimization Design of Functionally Graded Foam-Filled Graded-Thickness Tube Under Lateral Impact

International Journal of Computational Methods ◽

10.1142/s0219876218500883 ◽

2018 ◽

Vol 16 (01) ◽

pp. 1850088 ◽

Cited By ~ 4

Author(s):

Hanfeng Yin ◽

Jinle Dai ◽

Guilin Wen ◽

Wanyi Tian ◽

Qiankun Wu

Keyword(s):

Energy Absorption ◽

Wall Thickness ◽

Functionally Graded ◽

Design Parameters ◽

Foam Density ◽

Lateral Impact ◽

Multi Objective Optimization ◽

Foam Filled ◽

Thin Walled ◽

Graded Thickness

Foam-filled thin-walled structure has been widely used in vehicle engineering due to its highly efficient energy absorption capacity and lightweight. Unlike the existing foam-filled thin-walled structures, a new foam-filled structure, i.e., functionally graded foam-filled graded-thickness tube (FGFGT), which had graded foam density along the transverse direction and graded wall thickness along the longitudinal direction, was first studied in this paper. Two FGFGTs with different gradient distributions subjected to lateral impact were investigated using nonlinear finite element code through LS-DYNA. According to the parametric sensitivity analysis, we found that the two design parameters [Formula: see text] and [Formula: see text], which controlled the gradient distributions of the foam density and the tube wall thickness, significantly affected the crashworthiness of the two FGFGTs. In order to seek for the optimal design parameters, two FGFGTs were both optimized using a meta-model-based multi-objective optimization method which employed the Kriging modeling technique as well as the nondominated sorting genetic algorithm II. In the optimization process, we aimed to improve the specific energy absorption and to reduce the peak crushing force simultaneously. The optimization results showed that the FGFGT had even better crashworthiness than the traditional uniform foam-filled tube with the same weight. Moreover, the graded wall thickness and graded foam density can make the design of the FGFGT flexible. Due to these advantages, the FGFGT was an excellent energy absorber and had potential use as the side impact absorber in vehicle body.

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Crashworthiness Design and Multiobjective Optimization for Hexagon Honeycomb Structure with Functionally Graded Thickness

Advances in Materials Science and Engineering ◽

10.1155/2019/8938696 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Ruixian Qin ◽

Junxian Zhou ◽

Bingzhi Chen

Keyword(s):

Energy Absorption ◽

Optimization Design ◽

Surrogate Models ◽

Honeycomb Structure ◽

Functionally Graded ◽

Thickness Variation ◽

Static Compression ◽

Crashworthiness Optimization ◽

Energy Absorbing ◽

Graded Thickness

Higher energy absorption efficiency and better crashworthiness performance are always the key objectives for different energy absorbing structures applied in numerous industries including aerospace, rail equipment transportation, and automotive. In this study, a functionally graded thickness (FGT) design method is introduced in the design of a hexagon honeycomb structure to improve energy absorbing efficiency on the basis of a traditional honeycomb with uniform thickness (UT). The validation of a numerical analysis model for a UT honeycomb under axial loading is implemented by a nonlinear finite element code LS-DYNA (V971). Furthermore, the multiobjective crashworthiness optimization of an FGT honeycomb subjected to axial quasi-static compression is conducted to maximize specific energy absorption (SEA) and minimize peak crashing force (PCF). In addition, three surrogate models, including radial basis function (RBF), response surface method (RSM), and kriging (KRG), are compared in the accuracy of predicting SEA and PCF and capacity for optimization design of FGT honeycomb structure; the Nondominated Sorting Genetic Algorithm (NSGA-II) is applied to obtain the Pareto optimal solutions for the maximum thickness, minimum thickness, and thickness variation gradient exponent of a honeycomb wall. The optimal points obtained by different surrogate models subjected to an SEA value of 18.5 kJ/kg, 20 kJ/kg, 22 kJ/kg, and 24 kJ/kg are validated, and corresponding optimal parameters are compared; RBF and RSM are more suitable in crashworthiness optimization design of the FGT honeycomb structure. It is indicated that the FGT honeycomb with optimal geometrical parameters presents remarkable enhancement and energy absorbing potential compared to the traditional honeycomb structure.

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