The development of creep damage constitutive equations for low Cr-Mo alloy steel and its weldment at low stress

The ultimate objective of this research project is to develop creep damage constitutive equations for low Cr-Mo alloy and its weldment under low stress (0.2-0.4 yield stress,σ_Y). This paper summarizes a critical analysis on the cavity nucleation and growth and the deformation mechanisms and creep damage evolution characteristics at low stress with temperature ranging from 450 °C to 650 °C, in order to firmly establish the physical base for the theoretical constitutive modeling work. Moreover, it covers the influence of the stress level on the development of cavity nucleation and growth, leading to the final rupture, and proposes and discusses a new idea for failure criterion to be used in the constitutive equations under uni-axial stress state. This paper contributes to knowledge and the development of methodology

Equilibrium fluctuation for an anharmonic chain with boundary conditions in the Euler scaling limit

We study the evolution in equilibrium of the fluctuations for the conserved quantities of a chain of anharmonic oscillators in the hyperbolic space-time scaling. Boundary conditions are determined by applying a constant tension at one side, while the position of the other side is kept fixed. The Hamiltonian dynamics is perturbed by random terms conservative of such quantities. We prove that these fluctuations evolve macroscopically following the linearized Euler equations with the corresponding boundary conditions, even in some time scales larger than the hyperbolic one