Proposed optimum stiffness finder method for dynamic instability analysis of pyramidal lattice-core sandwich beam

Abstract

In this study, a novel method termed the Optimum Stiffness Finder (OSF) is introduced to determine the equivalent stiffness matrix for sandwich beams with lattice cores. The OSF method utilizes the Particle Swarm Optimization (PSO) algorithm to simplify the calculation of equivalent stiffness, addressing the challenges posed by the geometric complexity of lattice cores. This equivalent stiffness matrix is crucial for dynamic instability analysis, enabling the determination of dynamic instability regions that conventional finite element software does not calculate. For validation of the proposed method, the free vibration results of both three-dimensional finite element models developed in ABAQUS and OSF method are compared with results from the literature, confirming the accuracy of the finite element modeling. First, the free vibration results of three-dimensional finite element models developed in ABAQUS were compared with results from the literature, confirming the accuracy of the finite element modeling. Once validated, the ABAQUS models are used to obtain displacement values under uniform loading, which served as target data for the OSF algorithm. The OSF algorithm then optimized the stiffness matrix for Timoshenko beam theory in one-dimensional finite element analysis. The equivalent beam's vibration results are subsequently compared with those from the literature to ensure consistency and accuracy. The findings demonstrate the potential of the OSF method to streamline the dynamic stability analysis of lattice core sandwich beams, providing an efficient and accurate approach for engineering applications. © 2025 Institution of Structural Engineers