1. Torsion tests

1.1 The benefits of torsion testing

As we have just seen in the introduction, the determination of behavior laws using the classical tensile test is limited to a relatively low value of deformation. Compression testing is difficult to perform because of problems of specimen alignment and friction on the supports. Torsion testing is an interesting alternative. It is easy to implement, provided the necessary equipment is available. High strain rates can be achieved. When hot, it's possible to apply several dozen or even several hundred turns to the specimen without it breaking. The disadvantage of torsion testing is that stresses are not uniform throughout the specimen cross-section. The analysis of test results therefore requires special treatment. This follows from...