Fujita type global solvability to double nonlinear parabolic equation with nonlinear gradient term for the salt transfer process

In this paper we investigated the qualitative properties of non-negative and bounded continuous solutions to problem Cauchy for a degenerate parabolic equation with nonlinear gradient term. We based on splitting algorithm suggest estimate of weak solution for slowly, fast diffusion and critical cases, Fujita type global solvability of the Cauchy problem to degenerate type parabolic equation with nonlinear gradient term established. The theorems proven with comparison principle.

Interior micro-defect induced cracking mechanism and life prediction of carburized Cr-Ni steel based double nonlinear damage under variable amplitude loading

The variable amplitude loading fatigue test with interior Inclusion-FGA-Fisheye induced failure under R = 0 was carried out on carburized 12CrNi steel in very high-cycle fatigue regime. Comparing with S-N curve of constant amplitude loading, the total life is inevitably longer under variable amplitude loading. And, the surface morphology of FGA is coarser under same order of magnitude of fatigue life. Simultaneously, it can be determined that the formation micro-mechanism of FGA is caused by the continuous debondings of refined grains due to stress concentration around interior micro-defects, and variable amplitude loading will aggravate the formation of FGA. Furthermore, the life prediction model based on double nonlinear fatigue damage, which considers the coupling effect of local equivalent stress (surface residual stress, maximum stress and local stress concentration by RVE model), loading sequence and failure mechanism is established, and predicted life has good accuracy within the factor-of-three lines for experimental life.

Adhesion state estimation based on improved tire brush model

On the basis of calculating the longitudinal force using the original brush model, we simplify the tire structure and consider the lateral force generated by the lateral elasticity of the tread. At the same time, the boundary conditions between the adhesion area and the slip zone in the contact area of the tire are fully discussed. By establishing an improved tire brush model, the error caused by neglecting the sideslip characteristics is avoided, and the adaptability of the tire model is improved. A double nonlinear compensation method based on the lateral acceleration deviation and the yaw rate deviation is employed to estimate the road adhesion coefficient, which is closer to the actual attachment situation than the standard calculation. Based on this model, the vehicle stability coefficient k is defined and calculated to describe the stability of the vehicle during the driving process. The modeling results show that the value of k is always in the stable range of [0, 1]. Therefore, the vehicle that utilizes the improved tire brush model is always within the controllable range in the driving process, which verifies the effectiveness of the model.