Stress concentration factors (SCFs) at the root of an elliptic hole in unidirectional functionally graded material (UDFGM) plates under uniaxial and biaxial loads are predicted. ANSYS Parametric Design Language (APDL) was used to build the finite element models for the plates and to run the analysis. A parametric study is performed for several geometric and material parameters such as the elliptic hole major axis to plate width ratio, the elliptical shape factor, the gradation direction of UDFGM. It is shown that, SCF in the finite plate can be significantly reduced by choosing the proper distribution of the functionally graded materials. The present study may provide designers an efficient way to estimate the hole effect on plate structures made of functionally graded materials

Cellular structures are a favorite selection for the design of lightweight components and energy absorption applications due to several advantages such as their customizable stiffness and strength. In this investigation, functionally graded (FG) triply periodic minimal surfaces, Schoen-IWP (SIWP), and Schwarz primitive (SPrim) cellular structures were fabricated by masked stereolithography (MSLA) technique using ABS-like gray resin. The sample morphology, deformation behavior, mechanical characteristics, and energy absorption of graded and uniform structures were studied using experimental compression tests. The FG sample structures exhibited layer-by-layer collapse delaying shear failure. On the other hand, uniform samples showed complete diagonal shear failure. The total energy absorption to the densification point was 0.52 MJ/m³ and 0.58 MJ/m³ for graded and uniform SIWP, respectively. Additionally, the absorbed energy of the graded SPrim structure was 0.59 MJ/m³ while the uniform one absorbed 0.27 MJ/m³. The investigations showed that the graded SPrim absorbed more energy with high densification strain during the compression test.

Purpose: Inverse distance weighted (IDW) functions are utilized to make models of heterogenous materials such as functionally graded materials (FGM) in computer aided design (CAD). However, the use of IDW function based FGM for stress concentration reduction is scarcely available in the literature. The present work aims to analyze and reduce the stress concentration around a circular hole in IDW function-based finite FGM panel under biaxial loading.Design/methodology/approach: Extended finite element method (XFEM) model was prepared using MATLAB to investigate the effect of geometrical and material parameters on the stress concentration factor (SCF). The obtained results of IDW FGM are compared with homogeneous material as well as two different FGMs based on the power-law function.Findings: It was observed that the IDW function based FGM is simple in material modeling, conformal with all domain boundaries and shows lower stress concentration in comparison with the homogeneous material case. While comparing IDW FGM with power-law based FGMs, it was observed that the IDW FGM has least values of stress concentration for low d/W (diameter of the hole to panel width ratio) and is comparable with power-law based FGMs for high d/W.Originality/value: It can be stated that IDW FGM is highly suitable for stress concentration reduction in finite panels with d/W = 0.5, which can further be intended for obtaining optimum hole and panel designs.