Generation of Lattice Metamaterials with Optimal Mechanical Properties for Engineering Application

Abstract

The utilization of lattice metamaterials in many engineering disciplines has garnered growing attention as a result of improvements in additive manufacturing technology. The porous nature of these structures contributes to their ability to exhibit lightweight characteristics and robust mechanical properties. The microstructural design of a lattice structure has a considerable impact on the mechanical response on a macroscopic scale. Hence, it is crucial to improve the topological properties of the microstructure so as to enhance the overall performance of the lattice structure. This thesis examines several kinds of topology optimization approaches for creating topologically optimized lattice materials with enhanced mechanical performance that effectively tackle engineering challenges associated with the load-bearing and impact absorption capacities of lightweight materials. Density-based topology optimization methods are used to create novel lattice materials that have improved stiffness and energy absorption properties, specifically tuned for various mechanical loads. Furthermore, a design technique including the hybridization of topology is employed to customize the mechanical response and elastic anisotropy of the lattice materials. The proposed designs are additively manufactured using the Fused Deposition Modelling process, then mechanically characterized under quasi-static and dynamic loading conditions. The present research has resulted in the creation of a new type of lattice materials referred to Cuboidal Spherical Plate Lattice (CSPL) materials. These structures are made up of solid disks that are arranged in a cubic system and orientated along specific crystallographic directions. The utilization of the plate hybridization technique led to the formation of structures with greater material connectivity. This, in turn, improved the overall homogenized elastic and plastic mechanical properties, as well as the mechanical response when subjected to quasi-static compressive loading conditions. By employing linear topology optimization tasks, the stiffness of CSPLs is increased, leading to the creation of topologically optimized structures that exhibit superior uniaxial modulus, yield strength, and energy absorption capabilities compared to various lattice designs found in existing literature, such as honeycomb, TPMS, truss-, and platebased designs. Furthermore, nonlinear topology optimization tasks are executed to generate innovative lattice structures for enhanced energy absorption and impact resistance applications. Numerical and experimental investigations demonstrate the significance of improving the shearing resistance of lattice materials in order to improve their ability to absorb energy when exposed to quasi-static and low-velocity impact loading conditions. The thesis additionally develops numerical models for accurately simulating the deformation and failure of lattice materials involving large deformation and material nonlinearity. In essence, this thesis makes a valuable contribution to the current body of knowledge in the domain of lattice metamaterials and structural design, with implications for various engineering applications.

Date of Award	23 Apr 2024
Original language	American English
Supervisor	Imad Barsoum (Supervisor)