Building Block Based Topology Synthesis Algorithm to Optimize the Natural Frequency in Large Stroke Flexure Mechanisms

Abstract

Flexure based compliant mechanisms suited for a large range of motion can be designed by handling the challenges arising from combining low compliance in the desired directions, high support stiffness, low stresses and high unwanted natural frequencies. Current topology optimization tools typically can’t model large deflections of flexures, are too conceptual or are case specific. In this research, a new spatial topological synthesis algorithm based on building blocks is proposed to optimize the performance of an initial design. The algorithm consists of successive shape optimizations and layout syntheses. In each shape optimization the dimensions for some layout are optimized. The layout synthesis strategically replaces the most “critical” building block with a better option. To maximize the first unwanted natural frequency the replacement strategy depends the strain energy distribution of the accompanying mode shape. The algorithm is tested for the design of a 1-DOF flexure hinge. The obtained final layout agrees with results known from literature.