Dynamic response of flexible viscoelastic kerf structures of freeform shapes

Abstract

Kerfing which is also known as relief cutting is a technique used to create flexible freeform surfaces out of rigid planar surfaces. Due to their pleasing aesthetics, flexibility, and ability to be molded into desired freeform shapes, they have several potential applications in engineering and architecture. The flexibility and reconfigurability of kerf structures depend on several kerf parameters such as cut density, size of the unit cell, cut thickness, cut pattern, etc. This study focuses on using kerf structures to create freeform surfaces and understanding their dynamic response in terms of mode shapes, resonance frequencies, and stress wave propagation of reconfigurable large-scale kerf structures. The effect of kerf cut density and unit cell size on the unit-cell modal behaviors is first investigated using both mathematical modeling and experiments. A beam element model is used to capture deformations of kerf structures. Next, the shape reconfigurable behaviors of two kerf panels with uniform cut density and transitioning cut density are presented. The dynamic response of these two kerf panels is then examined. The analysis of large-scale kerf panels demonstrated the capability of the beam element model to capture the modal response of kerf panels. The flexibility of the kerf panels enables local and global shape reconfigurations, which can alter the dynamic response (i.e., modal response and stress wave propagation) of the kerf panels. We perform a comparative study on the effect of shape reconfiguration (local and global) on the modal response and stress propagation behavior of the kerf panel. Overall, these findings would help design kerf structures for indoor and outdoor architectures with desired performance requirements.