Topology synthesis of compliant mechanisms for nonlinear force-deflection and curved path specifications

Optimal design methods that use continuum mechanics models are capable of g enerating suitable topology, shape, and dimensions of compliant mechanisms for desired specifications. Synthesis procedures that use linear elastic fi nite element models are not quantitatively accurate for large displacement situations. Also, design specifications involving nonlinear force-deflectio n characteristics and generation of a curved path for the output port canno t be realized with linear models. In this paper, the synthesis of compliant mechanisms is performed using geometrically nonlinear finite element model s that appropriately account for large displacements. Frame elements are ch osen because of ease of implementation of the general approach and their ab ility to capture bending deformations. A method for nonlinear design sensit ivity analysis is described. Examples are included to illustrate the useful ness of the synthesis method.