57th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference at AIAA SciTech 2016 San Diego, California, USA 4-8 January 2016

AIAA-2016-1173

Multi-Functional Topology Optimization of Nanocomposite Beams

D. Seifert, M. Patil, G. Seidel, and G. Reich
Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0203, USA

This paper presents the design of a multi-functional beam cross section via the application of topology optimization. The cross section is composed of randomly oriented carbon nanotubes (CNT) in an epoxy matrix, and the volume fraction of CNT is allowed to vary at the local level within the cross section. Micromechanics models are applied to obtain properties such as effective Young’s Modulus, material resistivity, and piezoresistive constant. The objectives to be optimized include the minimization of the strain energy and the maximization of the resistance change due to strain (analogous to strain sensing signal strength). The sensitivities are calculated analytically and verified against a finite difference model. A deisgn variable filter is applied to reduce the influence of checkerboarding. A pareto front is generated comparing optimal topologies and their properties for different weights on the strain energy objective and the resistance change objective, respectively. What results is a preliminary design tool that would allow the engineer to select how much they value each objective and then use the method to create the ‘best’ design topology for their needs.