VARIATIONAL PRINCIPLE OF HYBRID ENERGY AND THE FUNDAMENTALS OF 3-D LAMINATE THEORY—A NEW APPROACH FOR THE ANALYSIS OF INTERLAMINAR STRESSES IN COMPOSITE LAMINATES

<正> This paper discusses the discuntinuity of stresses and strains at interlaminar surfaces of the eomposne laminate and presents a 3-D laminate theory for composite materials. This paper also presents a new type of clastic energy based on the globally continuous variables in laminates, different from the traditional potemial energy and complementary energy. Then. a variational principle corresponding to the 3-D laminate theory is developed. The theory and the principle could be a basis of verifying the 2-D lamimte theory and deterplining the interlaminar stresses mear the free edges.