It is widely known that the availability of lightweight structures with excellent energy absorption capacity is essential for numerous engineering applications. Inspired by many biological structures in nature, bio-inspired structures have been proved to exhibit a significant improvement over conventional structures in energy absorption capacity. Therefore, use of the biomimetic approach for designing novel lightweight structures with excellent energy absorption capacity has been increasing in engineering fields in recent years. This paper provides a comprehensive overview of recent advances in the development of bio-inspired structures for energy absorption applications. In particular, we describe the unique features and remarkable mechanical properties of biological structures such as plants and animals, which can be mimicked to design efficient energy absorbers. Next, we review and discuss the structural designs as well as the energy absorption characteristics of current bio-inspired structures with different configurations and structures, including multi-cell tubes, frusta, sandwich panels, composite plates, honeycombs, foams, building structures and lattices. These materials have been used for bio-inspired structures, including but not limited to metals, polymers, fibre-reinforced composites, concrete and glass. We also discussed the manufacturing techniques of bio-inspired structures based on conventional methods, and adaptive manufacturing (3D printing). Finally, contemporary challenges and future directions for bio-inspired structures are presented. This synopsis provides a useful platform for researchers and engineers to create novel designs of bio-inspired structures for energy absorption applications.

A review of recent research on bio-inspired structures and materials for energy absorption applications

Over the past several decades, a noticeable amount of research efforts has been directed to minimising injuries and death to people inside a structure that is subjected to an impact loading. Thin-walled (TW) tubular components have been widely employed in energy absorbing structures to alleviate the detrimental effects of an impact loading during a collision event and thus enhance the crashworthiness performance of a structure. Comprehensive knowledge of the material properties and the structural behaviour of various TW components under various loading conditions is essential for designing an effective energy absorbing system. In this paper, based on a broad survey of the literature, a comprehensive overview of the recent developments in the area of crashworthiness performance of TW tubes is given with a special focus on the topics that emerged in the last ten years such as crashworthiness optimisation design and energy absorbing responses of unconventional TW components including multi-cells tubes, functionally graded thickness tubes and functionally graded foam filled tubes. Due to the huge number of studies that analysed and assessed the energy absorption behaviour of various TW components, this paper presents only a review of the crashworthiness behaviour of the components that can be used in vehicles structures including hollow and foam-filled TW tubes under lateral, axial, oblique and bending loading.

https://myresearchspace.uws.ac.uk/ws/files/1765038/Paper_2.pdf

On the crashworthiness performance of thin-walled energy absorbers: Recent advances and future developments

A review on functionally graded structures and materials for energy absorption

The trade-off between obtaining a good distribution of Pareto-optimal solutions and obtaining them in a small computational time is an important issue in evolutionary multi-objective optimization (EMO). It has been well established in the EMO literature that although SPEA produces a better distribution compared to NSGA-II, the computational time needed to run SPEA is much larger. In this paper, we suggest a clustered NSGA-II which uses an identical clustering technique to that used in SPEA for obtaining a better distribution. Moreover, we propose a steady-state MOEA based on e-dominance concept and efficient parent and archive update strategies. Based on a comparative study on a number of two and three objective test problems, it is observed that the steady-state MOEA achieves a comparable distribution to the clustered NSGA-II with a much less computational time.

Towards a quick computation of well-spread pareto-optimal solutions

Energy absorption of metal, composite and metal/composite hybrid structures under oblique crushing loading

On hierarchical honeycombs under out-of-plane crushing

Parameterization of criss-cross configurations for multiobjective crashworthiness optimization

This paper introduces axial functionally graded thickness (AFGT) and lateral functionally graded thickness (LFGT) to thin-walled square structures separately, and then investigates their crashworthiness theoretically, numerically, experimentally under axial crushing load. The quasi-static axial crush experiments and the corresponding finite element models are first conducted to analysis the deformation mode and crushing force for uniform thickness (UT), AFGT and LFGT square tube under the same mass. Then, theoretical models predicting the mean crushing forces of AFGT and LFGT square tubes are established. The results show that both theoretical solutions and numerical results for FGT tubes agree well with the experimental results. Energy absorption characteristics between FGT and UT square tubes with same mass are compared based on the validated numerical models, which shows that AFGT square tube can effectively reduce the initial peak force compared to UT square tube while LFGT square tube remarkably surpasses the UT square tube in specific energy absorption ( SEA ) under axial crushing. Furthermore, parametric studies are performed to investigate the effects of gradient thickness variation on the energy absorption characteristics of AFGT and LFGT square tubes. The results again demonstrate that both AFGT and LFGT square tubes can improve the crashworthiness of thin-walled square tubes.

Tong Pang

Papers

On hierarchical honeycombs under out-of-plane crushing

Parameterization of criss-cross configurations for multiobjective crashworthiness optimization

Energy absorption mechanics for variable thickness thin-walled structures

Theoretical, numerical, and experimental study on laterally variable thickness (LVT) multi-cell tubes for crashworthiness

Energy absorption mechanism of axially-varying thickness (AVT) multicell thin-walled structures under out-of-plane loading