An Impact Protective Structure with Bistable Links

Abstract

This paper discusses a design concept of a protective structure with a special morphology that improves the impact resistance capability. We present a "bistable" structure concept: The bistable structure is designed so that the stress-strain relation is not unique. When the strain reaches a threshold, that part of the structure yields and subsequently fails. The remaining parts then carry the loads and maintain the structural integrity. The redistribution of the loads allows more energy of the collision to be absorbed.We describe the response of bistable structures in macro-and microscale, introduce a mesoscale damage tensor that measures the degree of damage in a small region, and numerically investigate a problem of projectile impacting a protective net. This paper introduces several effectiveness criteria of the protective bistable structure, and compares the structural responses of the bistable and conventional structure. The bistable structure dissipates more energy by creating a partial damage in a large area. Damage is understood as a process of irreversible phase transition from the initial to disintegrated state. Damage of the bistable structure is more stable; the cracks do not develop due to yielding of structural elements and damage delocalization.

Bistable Structures for Advanced Functional Systems

“…Similarly, Cherkaev et al proposed an impact protective structure consisting of bistable links as a shock resistance mechanism. [161] In their structure, the yielding behavior of certain links in the system (sacrificial links) was utilized as a protection for the active bistable links to improve energy absorption capacity.…”

Approaches to description of damageable lattices dynamics

“…To quantify the state of partially damaged structures, we naturally introduce a damage tensor that tracks the percentage of damaged links in different directions of the lattice in a small representative volume X. (Such a tensor has been suggested earlier (Betten, 1983;Cherkaev & Leelavanichkul, 2011;Skrzypek & Ganczarski, 2010;Wilson & Brannon, 2005), but its properties were postulated, now we compute it from the model. )…”

Compressive performance of 3D printed fault‐tolerant polymer lattice structures

“…Scholars have drawn inspiration from natural fault‐tolerant bone structures 32,33 and pearlitic structures 34,35 . One is to set the sacrificed unit in the structure 36 . When the strain increases to a certain threshold, the sacrificed unit fails, and the overall structure remains intact.…”

“…34,35 One is to set the sacrificed unit in the structure. 36 When the strain increases to a certain threshold, the sacrificed unit fails, and the overall structure remains intact. The other is to prevent the propagation of cracks and the initiation of secondary cracks by setting rigid inclusions in the material.…”