Design of Compliant Mechanisms
Updated: Mar 30
We use 2 design methods to obtain a compliant mechanism design for a prototype. They are as follows:
1. Pseudo Rigid Body Modeling
Pseudo-rigid-body models for individual flexible segments offer a simplified method of determining the deflections of large-deflection members. The availability of such a method for individual segments suggests its use to model more complex systems which include flexible segments. This pseudo-rigid-body model concept proves to be very useful in simplifying the analysis and synthesis of compliant mechanisms. Its advantage lies in its ability to develop a pseudo-rigid-body model of a compliant mechanism, and then use the large body of knowledge available in the field of rigid-body mechanism analysis and design. In this way, the pseudo-rigid-body model concept acts to unify compliant and rigid-body mechanism theories.
2. Topology optimization (TO)
A mathematical method that optimizes material layout within a given design space. This is for a given set of loads, boundary conditions, and constraints with the goal of maximizing the performance of the system. The result is then checked and optimized for manufacturability.
The conventional TO formulation uses a finite element method (FEM) to evaluate the design performance. The design is optimized using either gradient-based mathematical programming techniques such as the optimality criteria algorithm and the method of moving asymptotes or non gradient-based algorithms such as genetic algorithms. It involves considering quantities such as weight, stresses, stiffness, displacements, buckling loads and resonant frequencies.
Topology optimization can be extended to
• Size optimization: It considers structures which can be decomposed into finite number of members.
• Shape optimization: It allows extra freedom in configuration of the structure such as the location of connections between members.