Metallic perforated plate lattices with superior buckling strength
Lei Zhang, Mingpei Cang, Junhao Ding, Qingping Ma, Xiangyang Zhu, Lu Yang, Xu Song, Huachen Cui, Michael Yu Wang
Abstract
• A combined theoretical and numerical method based on the Rayleigh quotient is developed to design optimized micro hole locations. • Introducing micro holes at optimized locations for low-density plate lattices can improve the critical buckling stresses. • The post-buckling behavior and compressive strength of plate lattices are insensitive to micro holes. • Perforated plate lattices exhibit superior stiffness and compressive strength over truss and shell lattices in the considered density range. Plate lattices possess promising stiffness and yielding strength; however, their closed-cell topology dramatically increases the manufacturing difficulty. While introducing micro holes can effectively improve the manufacturability, design rationale to minimize the strength reduction induced by micro holes remain elusive. In particular, low-density plate lattices are prone to buckling failure, and design optimization for buckling strength is of great importance. Here, we propose a design method for low-density perforated plate lattices to achieve superior buckling strength using a Rayleigh quotient based theoretical criteria to determine the optimized locations of micro holes. Through linear buckling and post-buckling analysis, we demonstrate that introducing micro holes at the proposed locations can increase the critical buckling stresses and maintain the post-buckling compressive strength compared with the unperforated plate lattices. Three representative perforated plate lattices with the relative density range of 5.6%∼37.1% were fabricated with micro laser powder bed fusion process. Compression testing results show that the proposed perforated plate lattices exhibit superior Young’s modulus and compressive strength over shell and truss lattices in the considered relative density range.