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数学学院、所系列学术报告(820场):北京师范大学 李海刚教授

发表于: 2018-08-22 09:01  点击:

题目:  Babuska Problem in Composite Materials

报告人:  北京师范大学  李海刚  教授

时间:  2018年8月4日下午 2:00-3:00

地点:   数学楼627

摘要:  In high-contrast fiber-reinforced composite materials, the stress concentration  is a common phenomenon, which always causes damage initiation. The problem is modeled by a class of second order elliptic equations and systems of divergence form, with discontinuous coefficients.  For the original problem proposed by Ivo Babuska concerning the system of linear elasticity, we develop an iteration technique with respect to the energy integral to overcome the difficulty from the lack of maximal principle and obtain the optimal blow-up rates of the gradients when two inclusions are close to touch. Our results hold for convex inclusions with arbitrary shape and in all dimensions. For the scalar case, we further establish an explicit dependence of the derivatives on the ellipticity coefficients and the distance between interfacial boundaries of inclusions, which unifies the known results in the literature and answers two open problems proposed by Li-Vogelius (ARMA2000). This is based on a series of joint work with Professor Jiguang Bao (BNU), Yanyan Li (Rutgers) et al.