Doctoral Dissertations

Date of Award

12-1990

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Human Ecology

Major Professor

Randall R. Bresee

Abstract

Elastic constants of fibrous materials can not be easily determined experimentally using classical anisotropic theory of elasticity. Instead, constants are more easily computed theoretically using fiber-web theory since the only parameter appearing in constant-determination functions is the fiber orientation distribution function. However, no technique currently exists to measure this parameter conveniently and accurately. This Dissertation involves developing a method to measure the fiber orientation distribution. The method is based on electrical measurements. The fiber orientation distribution determined in this manner is especially suitable for use in elastic constant-determination functions since it takes into account the variable fiber cross-sectional area usually found in actual webs. Typical textile materials exhibit high electrical resistance and an instrument was designed to measure the low electric current conducted through webs. A theory based on the electrical field applied by the instrument also was developed to convert measured electrical currents to the fiber orientation distribution. Results were compared with both tensile testing and the actual distribution determined by counting fibers while webs were viewed with an optical microscope. Excellent agreements were found.

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