Out-of-plane deformation reduction via inelastic hinges in fibrous metamaterials and simplified damage approach

Abstract

The mechanical behavior of fibrous metamaterials is mainly determined by the interactions between the fibers composing the architecture. These interactions are usually of two different kinds: those directly depending on the positions of the fibers and those that need mediators, usually consisting of hinges, either inelastic or perfect, inducing restrictions on the kinematics of the fiber joints. In cases of interest, it has been observed that hinges can either have a certain torsional stiffness or behave as perfect joints, simply ensuring that the fibers remain interconnected, but not applying any constraint on the relative rotations between them. Here the effect of torsional stiffness of inelastic hinges is studied in two shear tests for a selected fibrous metamaterial. It is shown that the stiffness of hinges can be tailored to avoid, or at least reduce, out-of-plane deformations. Moreover, it is shown that, after reaching a threshold, permanent deformations are observed. This phenomenon is treated in a simplified way, by introducing damage in the continuum model.

Local–global DVC analyses confirm theoretical predictions for deformation and damage onset in torsion of pantographic metamaterial

“…A step toward the modeling of these mechanisms can be found in Refs. [51,52]. Since one of the interests of the torsion test lied in the fact that it exhibited a Poynting effect (Figure 4(b)), it was important to be able to have a numerical estimate of the reaction force and a prediction of the deformed shapes in an prescribed angular twist test.…”

“…This analysis can be conducted using the same pattern introduced in Ref. [52] to describe the onset of damage for pantographic structures with plastic hinges.…”

Investigating infill density and pattern effects in additive manufacturing by characterizing metamaterials along the strain-gradient theory

“…Specifically, the recent studies on pantographic structures have epitomized the importance of higher-gradient theories, especially for numerical predictions of such a complex structure. In order to investigate the mechanical behavior of pantographic structures, various higher-gradient models have been proposed [34][35][36][37][38] and examined through experiments [39][40][41][42][43][44], considering different mechanical phenomena [45][46][47][48][49][50]. We refer interested readers to the previous works [51][52][53][54] on different aspects of higher-gradient modeling.…”

Acoustic radiation from a sphere pulsating near an impedance plane using a boundary integral equation method

“…Hence, the vibro-acoustic fluid-structure interaction can be considered as ''feedback coupling'' [5]. Importantly, design and fabrication of new advanced materials has garnered a lot of attention due to recent progress in manufacturing and material technologies (e.g., see [6][7][8][9][10][11]), and therefore investigating such phenomena is of particular significance in the design of innovative metamaterials and new mathematical models [12][13][14][15][16][17][18].…”