Additive manufacturing and mechanical characterization of graded porosity scaffolds designed based on triply periodic minimal surface architectures.
Since the advent of additive manufacturing techniques, triply periodic minimal surfaces have emerged as a novel tool for designing porous scaffolds. Whereas scaffolds are expected to provide multifunctional performance, spatially changing pore patterns have been a promising approach to integrate mechanical characteristics of different architectures into a unique scaffold. Smooth morphological variations are also frequently seen in nature particularly in bone and cartilage structures and can be inspiring for designing of artificial tissues. In this study, we carried out experimental and numerical procedures to uncover the mechanical properties and deformation mechanisms of linearly graded porosity scaffolds for two different mathematically defined pore structures. Among TPMS-based scaffolds, P and D surfaces were subjected to gradient modeling to explore the mechanical responses for stretching and bending dominated deformations, respectively. Moreover, the results were compared to their corresponding uniform porosity structures. Mechanical properties were found to be by far greater for the stretching dominated structure (P-Surface). For bending dominated architecture (D-Surface), although there was no global fracture for uniform structures, graded structure showed a brittle fracture at 0.08 strain. A layer by layer deformation mechanism for stretching dominated structure was observed. For bending dominated scaffolds, deformation was accompanied by development of 45° shearing bands. Finite element simulations were also performed and the results showed a good agreement with the experimental observations.
Mechanical Engineering Department, Shahid Rajaee Teacher Training University, Tehran 16758-136, Iran.
M
M
Afshar
Mechanical Engineering Department, Shahid Rajaee Teacher Training University, Tehran 16758-136, Iran.
A Pourkamali
AP
Anaraki
Mechanical Engineering Department, Shahid Rajaee Teacher Training University, Tehran 16758-136, Iran.
H
H
Montazerian
Mechanical Engineering Department, Shahid Rajaee Teacher Training University, Tehran 16758-136, Iran; Institute for Materials Testing, Materials Science and Strength of Materials (IMWF), University of Stuttgart, Stuttgart, Germany. Electronic address: j.kad@srttu.edu.
J
J
Kadkhodapour
D001842:Bone and Bones; D020342:Finite Element Analysis; D008422:Materials Testing; D016062:Porosity; D023822:Tissue Engineering; D054457:Tissue Scaffolds
Additive manufacturing; Failure mechanism; Graded porous structures; Minimal surfaces