Warunek podobieństwa współczynnika skurczu poprzecznego w fotoplastyczności

The results of measurements of the lateral contraction coefficient v in the elastic-plastic deformation domain for celluloid and aluminium alloys PA2 and PA4 are presented. From the experiments it follows that the model similarity condition concerning the equality of the coefficient v for these materials is not fulfilled. The conclusion results from the observation that in the case of aluminium Poisson's ratio does not increase, after passing the elastic limit, to the limiting value of about 0.5; it remains constant and equal to the lateral contraction coefficient of purely elastic deformations.