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

It is widely known that the demand for lightweight structures with excellent energy absorption capacity is paramount in numerous engineering applications. Many publications have revealed that corrugated structures can collapse in a relatively controlled manner with a uniform force-displacement response and have remarkable energy absorption efficiency when compared with traditional structures without corrugations. The present work provides a comprehensive overview of recent advances in the development of corrugated structures for energy absorption applications, also considering the effects of corrugation characteristics on their crashworthiness. Such advanced energy absorbers include corrugated tubes, corrugated tapered tubes, corrugated beam and plates, corrugated honeycombs, corrugated core sandwich panels and other hybrid structures with complex corrugations. This review demonstrates that thin-walled structures with introduced corrugations can achieve more efficient and effective energy absorption. Finally, contemporary challenges of design and manufacture are discussed, as well as future directions for corrugated structures. This synopsis provides a useful platform for researchers and engineers designing corrugated structures for energy absorption applications.

Thin-walled corrugated structures: A review of crashworthiness designs and energy absorption characteristics

Comparative study on metal/CFRP hybrid structures under static and dynamic loading

The use of composite materials in several sectors, such as aeronautics and automotive, has been gaining distinction in recent years. However, due to their high costs, as well as unique characteristics, consequences of their heterogeneity, they present challenging gaps to be studied. As a result, the finite element method has been used as a way to analyze composite materials subjected to the most distinctive situations. Therefore, this work aims to approach the modeling of composite materials, focusing on material properties, failure criteria, types of elements and main application sectors. From the modeling point of view, different levels of modeling—micro, meso and macro, are presented. Regarding properties, different mechanical characteristics, theories and constitutive relationships involved to model these materials are presented. The text also discusses the types of elements most commonly used to simulate composites, which are solids, peel, plate and cohesive, as well as the various failure criteria developed and used for the simulation of these materials. In addition, the present article lists the main industrial sectors in which composite material simulation is used, and their gains from it, including aeronautics, aerospace, automotive, naval, energy, civil, sports, manufacturing and even electronics.

Application of the Finite Element Method in the Analysis of Composite Materials: A Review

Low-velocity impact resistance behaviors of bio-inspired helicoidal composite laminates with non-linear rotation angle based layups

Air voids produced in the manufacturing process have significant influence on the mechanical performances of single fiber bundle in carbon fiber-reinforced composites. The microscale finite element model of fiber bundle with voids is developed to predict mechanical properties and failure mechanisms. The failure responses of fiber and matrix in bundle are initiated by the maximum stress and Stassi failure criteria. The sudden stiffness degradation law is adopted to capture brittle behaviors. Both available theoretical models for voids and non-voids are used to validate the numerical model without voids and with different percentages of voids including 0.15, 0.5, 1, 2, 3, 4 and 5%. Effects of void contents on stress–strain responses of bundle are studied. The matrix damage development is studied regarding transverse compression and out-of-plane shear loading. The micro-stress analysis of matrix and voids in three-RUC model under different loadings is performed. The simulated elasticity and strength properties correlate well with theoretical results for voids and non-voids. The strengths and moduli gradually decrease with increasing void contents except longitudinal properties. The stress concentrations of bundle are mainly influenced by the loading direction.

Microscale finite element analysis for predicting effects of air voids on mechanical properties of single fiber bundle in composites

The crushing behaviors of thin-walled composite structures subjected to quasi-static axial loading are comparatively evaluated using four different failure initiation criteria. Both available crush...

Evaluations of failure initiation criteria for predicting damages of composite structures under crushing loading

The multi-scale finite element model is presented to analyze tension and ballistic penetration damage characterizations of 2D triaxially braided composite (2DTBC). At the mesoscopic level, the damage of fiber tows is initiated with 3D Hashin criteria, and the damage initiation of pure matrix is predicted by the modified von Mises. The progressive degradation scheme and energy dissipation method are adopted to capture softening behaviors of tow and matrix. The macro-scale damage model is established by maximum-stress criteria and exponential damage evolution. To simulate interface debonding and inter-ply delamination, a triangle traction–separation law is adopted in each scale. Both scale damage models are verified with available experimental results. Based on numerical predictions, the stress–strain responses and damage developments of 2DTBC under axial and transverse tension loading are studied. For ballistic penetration loading, the meso-scale damage mechanisms of 2DTBC are predicted using 1/4 model, 1/2 model, 1-layer model, 2-layer model and 3-layer model. Then, effects of different model and impactor radius on damage modes are analyzed. Additionally, the macro-scale ballistic penetration behaviors of 2DTBC are simulated and compared with experiment. The prediction results for tension and penetration correlate well with experiment results. Both tension and penetration damage characterizations for tow, matrix within tow, pure matrix, interface and inter-ply delamination are revealed. A comparison of penetration damage between meso- and macro-scale presents a similar crack mechanism between two scales.

Multi-scale finite element analysis for tension and ballistic penetration damage characterizations of 2D triaxially braided composite

The shear strength and progressive damage responses of 2D-triaxially braided composite (2DTBC) panel under shear loading are predicted by multi-scale modeling approaches. A micro-scale representative unit cell (RUC) model is built to calculate effective properties of bundle under six different loading conditions. At meso-scale, the 3D Hashin criterion and Stassi criteria are adopted to predict damage initiations of bundle and pure matrix. Both components are linearly degraded after damage initiations. A triangle traction-separation law is employed to capture the interface debonding. Effective properties are compared with Chamis’ model, which are used as input for meso-scale model. The shear stress-strain response of meso-scale RUC with different boundary conditions (BC) is verified with available experimental results. The shear damage behaviors are analyzed regarding stress distribution and damage characterization. The BC has great effect on shear loading and modulus. Damage modes of bundle, matrix in bundle, pure matrix and interface occur simultaneously. Both bias bundles severely suffer from damage.

Songjun Zhang

Papers

Low-velocity impact resistance behaviors of bio-inspired helicoidal composite laminates with non-linear rotation angle based layups

Microscale finite element analysis for predicting effects of air voids on mechanical properties of single fiber bundle in composites

Evaluations of failure initiation criteria for predicting damages of composite structures under crushing loading

Multi-scale finite element analysis for tension and ballistic penetration damage characterizations of 2D triaxially braided composite

Multi-scale analysis for mechanical properties of fiber bundle and damage characteristics of 2D triaxially braided composite panel under shear loading