Design of tailorable stiffness structures using L-system topology optimization

Within numerous disciplines, the ability to model and then optimize structures for a given application is of paramount importance to the design process. Topology optimization has been established as a valuable tool within such a structural design process as it allows for the realization of high-performing and non-intuitive material distributions within a design domain without the need for rigorous initial parameters. Traditional topology optimization methodologies are historically applied considering only static loading conditions consisting of a limited number of forces and displacements, thus optimizing desired performance metrics only under these conditions. As an alternative, this work proposes the use of a Lindenmayer System coupled with a graphbased interpreter known as Spatial Interpretation for the Development of Reconfigurable Structures (SPIDRS) to optimize the response of a structural topology over a range of loading magnitudes. The structures examined herein have the goal of matching their mechanical response under loading to an arbitrarily defined stiffness curve. Consequently, this work is one of the first to employ topology optimization in the generation of a structure with a specified behavior across a range of loading conditions. It will be shown that the L-System/SPIDRS framework enables the design of structures which produce a desired reaction force at each of many defined displacements in both tensile and compressive loading conditions.