NEW POINTS-OF-VIEW ON THE NONLOCAL FIELD-THEORY AND THEIR APPLICATIONS TO THE FRACTURE-MECHANICS (I) - FUNDAMENTAL THEORY

In the linear nonlocal elasticity theory, the solution to the boundary -value problem of the crack with a constant stress boundary condition does not exist. This problem has been studied in this paper. The conte nts studied contain of examining objectivity of the energy balance, de ducing the constitutive equations of nonlocal thermoelastic bodies, an d determining nonlocal force and the linear nonlocal elasticity theory . Some new results are obtained. Among them, the stress boundary condi tion derived from the linear theory not only solves the problem mentio ned at the beginning, but also contains the model of molecular cohesiv e str ess on the sharp crack tip advanced by Barenblatt.