A proof of the convexity of the set of lamination parameters

Abstract

In this paper we show that the proof of the convexity of the set of lamination parameters given by J.L. Grenestedt and P. Gudmundson, which is extensively cited in the literature, is not correct. We give a proof of the convexity of this set when the class of functions which gives the layup angle as a function of the through-the-thickness coordinate is the set of step functions.