This book presents fundamental theoretical and experimental studies of well- known scientists in solid mechanics, hydromechanics, aeromechanics, biomechanics, etc. These studies relate to contact and mixed problems of the theory of elasticity and viscoelasticity, tribology, fracture mechanics, electroelasticity, magnetoelasticity, as well as to the theory of anisotropic shells and plates and are aimed at application in various areas of engineering practice. The book is devoted to the 110th birthday of academician N.Kh. Arutunyan.