SEDL / STP / STP877-EB / STP32882S

A Low-Cost Microprocessor-Based Data Acquisition and Control System for Fatigue Crack Growth Testing

Sooley, PM
MTS graduate research fellow and Cockburn professor of engineering design, University of Toronto, Toronto, Ont.

Hoeppner, DW
MTS graduate research fellow and Cockburn professor of engineering design, University of Toronto, Toronto, Ont.

Pages: 17    Published: Jan 1985

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Abstract

The requirements for obtaining economic fatigue crack growth data from the threshold regime to instability in inert, gaseous, elevated-temperature, and aqueous environments necessitate the development of remote crack growth monitoring techniques. Two of these processes used extensively are the compliance method and the potential-drop method.

The performance of a microprocessor-based machine controller and data acquisition system utilizing the d-c potential-drop method of monitoring crack length is presented. The development of software for performing K-increasing and threshold tests and their compliance with the present ASTM standards are discussed. The successful development and use of the machine are shown by the results obtained during round-the-clock testing for acquiring crack growth data for a titanium alloy.