SEDL / STP / STP521-EB / STP36482S

Method for Estimating Fracture Strength of Specially Orthotropic Composite Laminates

Konish, HJ
Graduate student and associate professors, Carnegie Institute of Technology, Carnegie-Mellon University, Pittsburgh, Pa.

Cruse, TA
Graduate student and associate professors, Carnegie Institute of Technology, Carnegie-Mellon University, Pittsburgh, Pa.

Swedlow, JL
Graduate student and associate professors, Carnegie Institute of Technology, Carnegie-Mellon University, Pittsburgh, Pa.

Pages: 10    Published: Jan 1973

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Abstract

A method is presented for estimating the stress intensity factor characteristic of crack extension in a specially orthotropic advanced fiber composite laminate, based on the elastic properties and ultimate principal strengths of a lamina, the laminate construction, and the experimentally determined value of the characteristic stress intensity factor of an arbitrary angle-plied, midplane symmetric laminate. A comparison of the results obtained from this method with limited experimental data for graphite/epoxy laminates indicates that the method is quite accurate for this particular material system.

The predictive method is also used, in conjunction with experimental data, to estimate the size of a damage zone surrounding the crack tip. The implications of the size of this damage zone are discussed briefly.