ISSN: 1546-962X
Published Online: 10 March 2004
Page Count: 23

Fiber-Matrix Adhesion Measured By the Micro-Indentation Test: Data Reduction Based On Real Time Simulation

Al-Ostaz, A
Assistant Professor,University of Mississippi,MS,

Drzal, LT
University Distinguished Professor,Composite Materials and Structures Center, Michigan State University,MI,

Schalek, RL
Research Specialist,Composite Materials and Structures Center, Michigan State University,MI,

(Received 1 May 2003; accepted 24 October 2003)

Abstract

In this paper, we present a real time data reduction technique for calculating the interfacial shear stress measured by the micro indentation test in real composite samples, which can significantly improve the quality of the data. The model takes into account selected local geometric distribution of the fibers, shape and size of the indenter, friction between the indenter and the fiber, and residual stresses due to thermal loading. Material properties can be nonlinear and non-isotropic. As a result, fiber selection for testing is less restrictive, residual stresses can be included in the IFSS calculation, indenter size and shape are included in the calculation, and the fiber end/free surface singularity is taken into account. In addition to the Interfacial Failure Shear Stress (IFSS) calculation, the tensile stress in the fiber is calculated, and the load-displacement curve is generated. As a result, this real-time model significantly reduces the standard deviation and covariance compared to the conventional model, thermal and mechanical contributions to the measured interfacial shear strength are decoupled, and incorporation of continuous loading testing is possible.

Keywords:
composite, interface, indentation, shear strength, fracture

Paper ID: JAI11934
DOI: 10.1520/JAI11934
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