Toward Characterization of Variable-Amplitude Fatigue Crack Growth Properties

Abstract

Variable-amplitude fatigue crack propagation (VAFCP) involves load history effects whose characterization falls beyond the scope of prevailing constant-amplitude fatigue crack growth testing practices such as those outlined in ASTM E647. Test procedures are described for reproducible laboratory characterization of three independent material properties that are crucial to experimental and analytical study of VAFCP. The new test procedures require dedicated application software that can operate with existing computer-controlled test equipment and instrumentation. They can be readily applied to standard laboratory test coupons currently used for fatigue crack growth testing.