A novel adaptive control system for a custom-built tension-torsion machine

Mathematical theories of elasticity-plasticity have received considerable development in recent years. However, the quantity of accurate experimental work, carried out to examine the validity of these theories appears to be limited. As the theories have increased in sophistication, the accuracy to which the experiments must be performed has also increased. In this paper the development and application of a novel adaptive control system for performing combined tension and torsion experiments on solid and tubular specimens is described. National Instruments LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is used to control the axial and torsional loads on the specimen through data acquisition boards. LabVIEW software in conjunction with data acquisition board, servo-controllers and servomotors form the adaptive control system for the custom-built tension-torsion machine. Accurate control of the axial and torsional loads in the specimen is achieved with the application of the adaptive control system and a sample of the test results are presented in this paper.