NOVEL COMPUTER-CONTROLLED CONSTANT STRESS LEVER ARM CREEP TESTING MACHINE

A high speed computer interface and closed-loop feedback. control syst em has been integrated into an existing, mechanical lever-arm, constan t load, high temperature creep testing machine to shed load as a funct ion of decreasing cross-sectional area such that a state of constant s tress can be obtained throughout the test duration. This allows a comp uter interface and the custom designed mechanical load shedding appara tus to precisely control the applied stress in response to any changes in the specimen's measured resistance to deformation during a materia l evaluation test. A background analysis of typical mechanical creep m achines and the design concepts and technical innovations related to t he novel apparatus presented in this work will be discussed in detail. (C) 1997 American Institute of Physics.