Showing papers by "Rashid K. Abu Al-Rub published in 2023"

Gyroid-like metamaterials: Topology optimization and Deep Learning

Abstract: Triply periodic minimal surface (TPMS) metamaterials characterized by mathematically-controlled topologies exhibit better mechanical properties compared to uniform structures. The unit cell topology of such metamaterials can be further optimized to improve a desired mechanical property for a specific application. However, such inverse design involves multiple costly 3D finite element analyses in topology optimization and hence has not been attempted. Data-driven models have recently gained popularity as surrogate models in the geometrical design of metamaterials. Gyroid-like unit cells are designed using a novel voxel algorithm, a homogenization-based topology optimization, and a Heaviside filter to attain optimized densities of 0-1 configuration. Few optimization data are used as input-output for supervised learning of the topology optimization process from a 3D CNN model. These models could then be used to instantaneously predict the optimized unit cell geometry for any topology parameters, thus alleviating the need to run any topology optimization for future design. The high accuracy of the model was demonstrated by a low mean square error metric and a high dice coefficient metric. This accelerated design of 3D metamaterials opens the possibility of designing any computationally costly problems involving complex geometry of metamaterials with multi-objective properties or multi-scale applications.

Dynamics of Suspended Cable Driven Parallel Robots Using the Geometric Variable Strain Approach

Abstract: Construction 3D printing technology has recently received significant attention as a method for creating construction components or printing entire buildings. The deployment of Cable Driven Parallel Robots (CDPRs) in large-scale 3D printing is being explored as a potential candidate due to their low cost, high speed, and design modularity. However, the cable's inertial and elastic properties may lead to sagging and vibration, making the system difficult to model. In this paper, we use the Geometric Variable Strain (GVS) model, a geometrically exact approach based on the Cosserat rod theory, to model the dynamics of a CDPR. The Cosserat rod theory accounts for deformation modes that are not considered in other models, while the geometric formulation ensures accurate and fast computation. We compare the dynamic simulation of a small-scale CDPR prototype at different speeds and with an experimental setup. We also study the dynamics of a large-scale system subject to step loading. We show that analyses of CDPR systems using the GVS approach can reveal new perspectives on their control, design, and development.