Modeling and Computer Simulation of the Compressional Behavior of Fiber Assemblies

Abstract

A model is presented that allows prediction of the properties of a fiber assembly under compression from the physical properties of its component fibers, taking into account both static and kinetic friction. Unlike previous models, this model is not based on the assumed behavior of idealized bending elements. Computer simulations are run for four cases with two different friction conditions in order to compare predictions of this model with experimental results and with van Wyk's theory of the uniaxial compression of an initially random fiber assembly. These simulations are the first to show a reasonable ability to predict the undeter mined constant K in van Wyk's equation. They also show a significandy greater number of fiber-fiber contacts being formed than theories based only on the diameter and arrangement of fibers have predicted. The predicted contacts have a wide range of contact forces, while only a small percentage of them do not slip. Further improvements to the predictive abilities of this model may be obtained by running larger simulations, modifying the boundary conditions, and incorporating a more realistic friction model.

Effective thermal conductivity and thermal contact resistance of gas diffusion layers in proton exchange membrane fuel cells. Part 2: Hysteresis effect under cyclic compressive load

“…The compression hysteresis was theoretically modeled and verified against experimental data in [17][18][19] by applying the force, angular momentum, and bending equations to fiber assemblies. These models [17][18][19] reproduced the experimentally observed trends correctly but the values are different. Also, the hysteresis effect was independent of the number of load cycles as a result of neglecting the viscoelastic behavior of the fibers.…”

“…Also, it does not explain the non-recoverable strain during compression and the mechanical hysteresis during compression-release cycling. Recent studies [15][16][17][18][19][20] have focused on accounting for the fiber slippage and the hysteresis observed during compression-release cycling. The cycling induces energy dissipation as a result of viscous damping or frictional losses.…”

Fabric Handle and Its Basic Mechanical Properties

“…Jeong and Kang [103] analyzed compressional deformation of woven fabrics using FEM. Beil and Roberts [104,105] modeled the compressional behavior of fiber assemblies and the effects of hysteresis, crimp and orientation were studied. Taylor and Pollet [106] tried to explain dynamic compression by a Kelvin-Voigt model.…”

Elastocapillarity: Stress transfer through fibrous probes in wicking experiments

“…On the other hand, the fibrous materials have some characteristic features that cannot be straightforwardly described by classical poroelasticity models [21][22][23][24]. For example, one can easily stretch the fabric without significantly changing the fabric thickness.…”