Comparison of Mechanical Properties and Energy Absorption of Sheet-Based and Strut-Based Gyroid Cellular Structures with Graded Densities.

Dawei Li,Yi Min Xie,Ning Dai,Wenhe Liao

doi:10.3390/ma12132183

Dawei Li, Yi Min Xie + Show 2 more

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https://doi.org/10.3390/ma12132183

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Abstract

Bio-inspired functionally graded cellular materials (FGCM) have improved performance in energy absorption compared with a uniform cellular material (UCM). In this work, sheet-based and strut-based gyroid cellular structures with graded densities are designed and manufactured by stereo-lithography (SLA). For comparison, uniform structures are also designed and manufactured, and the graded structures are generated with different gradients. The mechanical behaviors of these structures under compressive loads are investigated. Furthermore, the anisotropy and effective elastic modulus of sheet-based and strut-based unit gyroid cellular structures are estimated by a numerical homogenization method. On the one hand, it is found from the numerical results that the sheet-based gyroid tends to be isotropic, and the elastic modulus of sheet-based gyroid is larger than the strut-based gyroid at the same volume fraction. On the other hand, the graded cellular structure has novel deformation and mechanical behavior. The uniform structure exhibits overall deformation and collapse behavior, whereas the graded cellular structure shows layer-by-layer deformation and collapse behavior. Furthermore, the uniform sheet-based gyroid is not only stiffer but also better in energy absorption capacity than the uniform strut-based gyroid structure. Moreover, the graded cellular structures have better energy absorption capacity than the uniform structures. These significant findings indicate that sheet-based gyroid cellular structure with graded densities have potential applications in various industrial applications, such as in crashworthiness.

Highlights

Graded cellular materials (FGCM) are widely found in nature, have a relatively low-density with high strength, excellent energy absorption, and thermal conductivity [1]
The results demonstrate that the energy absorption capacity of the graded cellular materials of the two process conditions were superior to that of the uniform cellular materials
We studied the structural mechanical behavior and energy absorption capacity of the

Summary

Introduction

Graded cellular materials (FGCM) are widely found in nature, have a relatively low-density with high strength, excellent energy absorption, and thermal conductivity [1]. Cellular materials are formed during bulk processing, such as foaming to obtain random foam materials or to establish lattice structures by processes such as adhesion, welding, and extrusion [2]. These methods are difficult to obtain a graded cellular material, while variable density graded cellular materials have been shown to have better mechanical properties and energy absorption capabilities [3]. Additive manufacturing (AM) techniques have made it possible to manufacture complex graded materials and structures, which make them potentially useful in biomedical, aerospace, and automotive applications [4].

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