Abstract: A piezoelectric load cycle counter is provided for a multi-stationed strain-life tester. A plurality of test specimens are interposed between a fixed upper bracket and a lower reciprocating bracket and are cyclically flexed therebetween. Piezoelectric crystals maintained in association with the upper bracket with each of the test stations present an output signal on each flexure of the test specimen. These output signals enable a counter which counts the number of cycles of the lower bracket. When a specimen breaks, the output signal of the associated station terminates and the count for that station similarly terminates.

Abstract: Apparatus for monitoring and measuring the growth of a crack in an elastic specimen. The specimen is repeatedly flexed by a piston at a set frequency and periodically slowed to a substantially lower frequency during which time a line scan camera monitors the length of the crack. The camera is positioned such that the specimen is drawn through the scan line thereof. The camera is calibrated such that the output signal from the camera correlates directly to the cracklength. This output signal is digitized, received, and stored by a digital processor for use in determining the crack growth rate.