Location

La Jolla, CA

Start Date

1-1-1998 12:00 AM

Description

The fundamental strain mechanisms of Ceramic Matrix Composites are the matrix microcracking that induces a loss of stiffness and the fiber-matrix debonding that leads to interfacial frictional sliding [1]. The interfacial sliding stress is thus a key parameter in the global behavior. The use of an experimental device coupling an ultrasonic immersion tank to a tensile machine and an extensometer allows to detect the anisotropy of the damage mechanisms of a material as well as to perform a strain partition under load because it makes it possible to identify the elastic tensor variation. The inelastic strain identified this way comes from the transverse cracks opening due to both the fiber/matrix elasticity mismatch and relative sliding at the interface. It is then possible to assess the value of the interfacial sliding stress with a micromechanical model derived from the analytical expressions of the elastic properties of a fibrous composite containing cracks and a shear-lag analysis. This can be done because the experimental variation of the compliances gives access to the constitutive law of the transverse crack densities and allows to estimate the debonding length.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

17B

Chapter

Chapter 5: Engineered Materials

Section

Composites

Pages

1193-1200

DOI

10.1007/978-1-4615-5339-7_154

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Evaluation of the Interfacial Sliding Stress of Ceramic Matrix Composites Under Tensile Loading

La Jolla, CA

The fundamental strain mechanisms of Ceramic Matrix Composites are the matrix microcracking that induces a loss of stiffness and the fiber-matrix debonding that leads to interfacial frictional sliding [1]. The interfacial sliding stress is thus a key parameter in the global behavior. The use of an experimental device coupling an ultrasonic immersion tank to a tensile machine and an extensometer allows to detect the anisotropy of the damage mechanisms of a material as well as to perform a strain partition under load because it makes it possible to identify the elastic tensor variation. The inelastic strain identified this way comes from the transverse cracks opening due to both the fiber/matrix elasticity mismatch and relative sliding at the interface. It is then possible to assess the value of the interfacial sliding stress with a micromechanical model derived from the analytical expressions of the elastic properties of a fibrous composite containing cracks and a shear-lag analysis. This can be done because the experimental variation of the compliances gives access to the constitutive law of the transverse crack densities and allows to estimate the debonding length.