Volume 14, Issue 3 (May 1986)
A Personal Computer Based Thermal-Mechanical Fatigue Test System
A materials testing apparatus is described which employs two closed feedback control loops simultaneously; one loop controls thermal cycling (i.e., specimen temperature cycling), while the other controls mechanical cycling (i.e., strain cycling). Although numerous variations of TMF (thermal-mechanical fatigue) test stations have been reported previously, several unique features justify a description of the current system: (1) thermal and mechanical control cycles are individually controlled using remotely programmable, arbitrary waveform function generators; (2) a personal computer is used to coordinate data acquisition and monitoring of critical test parameters; and (3) a method of real-time separation of temperature induced strain and mechanically induced strain has been incorporated. The system is currently being used to simulate actual operating conditions to which turbine engineering alloys are exposed during start-up and steady-state operation.