Inverse Synthesis of 3D Spectral Metamaterials for RF and Nano-applications

Figure: Optimal designed and fabricated anisotropic electromagnetic material with off the shelf dielectric constituents

With specific reference to electromagnetic applications, the possibility of obtaining new materials with prescribed anisotropy, dispersion and nonlinearity over a wide frequency band is of utmost importance.

Design and Fabrication of Deformable Antenna Substrates

In a variety of key problems, the research approach pays attention in bridging synthesis/analysis (engineering) with practical realization (materials science) of complex devices which leads to the broader definition of the research theme as the “Automated Design and Realization of Complex Material Systems”

Hence, the primary objective of Dr. Kiziltas is to understand, design and optimize new materials and composites and finally fabricate them with desired new properties for device performance enhancements and/or miniaturization purposes. A clear understanding of engineered composites requires an interdisciplinary thought process, grounded in a sound fundamental knowledge of traditional composite materials and a powerful design tool.

Figure: Fabricated deformable polymer-ceramic functionally graded substrates using tape casting (left) and freeze drying (right)

Peridynamics Topology Optimization for Additive Manufacturing

Peridynamics (PD) is a new nonlocal continuum mechanics formulation. Its equations are always applicable whether there is any discontinuity in the structure or not due to the non-derivative (i.e., purely integral) nature of the theory. On the other hand, topology optimization can be considered as finding an optimal distribution of material deposition (i.e., where should the material be?) whilst improving an objective function (e.g., stiffness) and satisfying design constraints.

We recently developed a novel peridynamics topology optimization (PD-TO) algorithm to perform structural optimization of engineering components involving damages/cracks/failures. As depicted in Figure 1, this new concept allows engineers to model existence of damage as a constraint during geometrical optimization process. In addition, the PD-TO approach simply eliminate the limitations encountered when performing the topology optimization analysis using traditional finite element methods especially for problems involving moving boundaries, large deformations, and cracks/defects.

 Figure 1. Optimum topologies obtained from PD analysis.

Moreover, various three-dimensional topology optimization algorithms have been developed for additive manufacturing of structures. During topology optimization stages, the mechanical/manufacturing constraints including minimum feature size, overhang supports angle, selective print directions are considered for rapid prototyping of an optimized geometry. The fundamental solution methods contain comprehensive combination of different modelling techniques such as PD, finite element methods, other continuum formulations. Hence, vital mechanical parameters including residual stress, stress-induced cracks, thermomechanical damages can be viably considered during topology optimization. Various geometry smoothing methods are implemented on the geometry being optimized, thereby producing ready-to-print structures (i.e., with/without consideration of cracks) as shown in Figure 2.

Figure 2. Peridynamics topology optimization: Towards print-ready design for additive manufacturing.