Ajit Panesar

An investigation into reinforced and functionally graded lattice structures

Lattice structures are regarded as excellent candidates for use in lightweight energy-absorbing applications, such as crash protection. In this paper we investigate the crushing behaviour, mechanical properties and energy absorption of lattices made by an additive manufacturing process. Two types of lattice were examined: body-centred-cubic (BCC) and a reinforced variant called BCC z . The lattices were subject to compressive loads in two orthogonal directions, allowing an assessment of their mechanical anisotropy to be made. We also examined functionally graded versions of these lattices, which featured a density gradient along one direction. The graded structures exhibited distinct crushing behaviour, with a sequential collapse of cellular layers preceding full densification. For the BCC z lattice, the graded structures were able to absorb around 114% more energy per unit volume than their non-graded counterparts before full densification, 1371 ± 9 kJ/m3 versus 640 ± 10 kJ/m3. This highlights the strong potential for functionally graded lattices to be used in energy-absorbing applications. Finally, we determined several of the Gibson–Ashby coefficients relating the mechanical properties of lattice structures to their density; these are crucial in establishing the constitutive models required for effective lattice design. These results improve the current understanding of additively manufactured lattices and will enable the design of sophisticated, functional, lightweight components in the future.

Design Framework for Multifunctional Additive Manufacturing: Placement and Routing of Three-Dimensional Printed Circuit Volumes

A framework for the design of additively manufactured (AM) multimaterial parts with embedded functional systems is presented (e.g., structure with electronic/electrical components and associated conductive paths). Two of the key strands of this proposed framework are placement and routing strategies, which consist of techniques to exploit the true-3D design freedoms of multifunctional AM (MFAM) to create 3D printed circuit volumes (PCVs). Example test cases are presented, which demonstrate the appropriateness and effectiveness of the proposed techniques. The aim of the proposed design framework is to enable exploitation of the rapidly developing capabilities of multimaterial AM.

A METHOD FOR BI-DIRECTIONAL COUPLING OF STRUCTURE AND SYSTEM IN THE OPTIMISATION OF MULTI-FUNCTIONAL COMPONENTS

The driver for this research is the development of multi-material additive manufacturing processes that provides the potential for multi-functional parts to be manufactured in a single operation. To exploit the potential benefits of this emergent technology, new design, analysis and optimization methods are needed. This paper proposes a method in which a multifunctional part, consisting of a system, comprised of a number of connected functional components within a mechanical structure, can be optimized. The main contribution of this paper is the coupling strategy that enables the structural topology optimization (TO) of a part to be carried out in conjunction with the internal system design. This is achieved by accommodating the effects of system integration on the structural response of the part within TO. The method is demonstrated by performing a coupled optimization on a cantilever plate with integrated components and circuitry. The results demonstrate that the method is capable of designing an optimized multifunctional part in which both the structural and system requirements are considered.