Lakhasly

In fact the yield point in this case will be significantly less than the corresponding yield stress in tension.This reduction in yield stress is known as the Bauschinger effect.The presence of the Bauschinger effect complicates any plasticity theory.1.

If one takes a virgin sample and loads it in tension into the plastic range, and then unloads it and
continues on into compression, one finds that the yield stress in compression is not the same as the yield
strength in tension, as it would have been if the specimen had not first been loaded in tension. In fact
the yield point in this case will be significantly less than the corresponding yield stress in tension. This
reduction in yield stress is known as the Bauschinger effect. The effect is illustrated in Fig. 1. The
solid line depicts the response of a real material. The dotted lines are two extreme cases which are used
in plasticity models; the first is the isotropic hardening model, in which the yield stress in tension and
compression are maintained equal, the second being kinematic hardening, in which the total elastic
range is maintained constant throughout the deformation.
The presence of the Bauschinger effect complicates any plasticity theory. However, it is not an issue
provided there are no reversals of stress in the problem under study.