A continuum model for needlepunched nonwoven fabrics

Nonwoven fabrics are sheet structures created by bonding or interlocking a web (network) of fibers through mechanical, thermal or chemical processes. In general, the mechanical response of nonwoven fabrics exhibits two major characteristics. First, the mechanical response can vary significantly when the fabric is loaded along different directions, depending on the existence of a preferential orientation in the fiber arrangement and/or in the pattern of inter-fiber bonding/entanglement. Second, the mechanisms of deformation include elastic and inelastic components, accompanied by an irrecoverable evolution of the texture of the fiber network. In this work, we propose a three-dimensional, large strain continuum model for the constitutive behavior of nonwoven fabrics that accounts for the fiber network characteristics responsible for its anisotropic behavior, and captures the effects of deformation mechanisms at the micro-scale (fiber and bonds/entanglement) level. The model consists of two constitutive components: a nonlinear elastic component representing the resistances to recoverable deformation mechanisms, and a non-linear inelastic component representing the resistances to irrecoverable deformation and texture evolution. For nonwoven fabrics in which the anisotropy of fiber orientation is combined with random entanglement processes, we propose to capture the combined effects of fibers and junctions orientation distributions using a single tensorial representation of the network anisotropy (fabric ellipsoid). An orthotropic elastic constitutive model for the elastic response of nonwoven fabrics is then formulated based on this structural measure and deformation mechanisms of the network structure. The inelastic component of the model is then prescribed in terms of an evolution law for the fabric ellipsoid.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Jearanaisilawong, Petch, 1979-

Advisor dc:contributor.advisor

• Simona Socrate.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/44751

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/44751