Coarse-grained Mg in the as-cast condition and fine-grained Mg in the extruded condition were processed by high pressure torsion (HPT) at room temperature for up to 16 turns. Hardness anisotropy and texture data results suggest that texture strengthening plays an important role for both types of samples. Texture strengthening weakens with decreasing grain size.

Experiment research aiming at the anti-explosion capability of the refuge chamber is a complex work with high costs. By using finite element analysis, however, could avoid this issue and implement the simulation and analysis more effectively. Based on transient dynamics approach, numerical simulation calculation and analysis of the dynamic response of the refuge chamber under the impact caused by gas explosion are presented in this paper. The results indicate that, when the refuge cabin under specified explosion impact wave stress, the maximum stress of the cabin is 370.8MPa,which is under the ultimate strength, and the maximum impact wave deformation of the cabin is 9.43mm, which is under the maximum permissive deformation (20mm), therefore the rigidity and the strength of the cabin both meet the demands. The refuge chamber presented in this paper, which remain the integrity of the cabin and the safety of the structure under specified explosion impact, has good anti-explosion ability, and could implemmet the emergency risk avoiding effectively.

The mechanics properties of a certain automobile rear axle shell were studied and a large displacement, large strain elastoplastic finite element analysis was carried out. and the followings were obtained: the load-displacement curve at loading point, elastoplastic strain-load curve at the maximum stress point, elastoplastic stress-load curve in dangerous cross-section, and the yielding load at which the dangerous cross-section overall yield. The results show that elastoplastic finite element simulation results are much closer to the experimental corresponding results. Through optimization design in manufacturing system, the weight of the rear axle shell is greatly reduced as compared with the original design. Optimal design not only saves materials and reduces cost, but also greatly reduces the design time. The calculation results provide the necessary data for automobile rear axle design, strength evaluation and fatigue life estimate.

For Ramberg-Osgood elasto-plastic material, under the premise that integration path is limited through the Gaussian integration points, the finite element expressions of the J- integral were deduced in detail. Using the method of coordinate transformation, integration was conducted through the plane rs of the shell element local coordinate system rst (t for shell element thickness direction). The integration points on mid-surface of the shell element were considered. Thus the finite element expressions of the J- integral can be applied to shell elements, the J- integral calculation problem of the shell structure with crack can be solved. A lot of standard sample results comparisons show that the calculation precision of the method proposed in this paper meet the requirements of engineering. Finally, the J- integral of a pressure vessel (a cylindrical shell with a hole and unilateral axial crack) was calculated. The obtained results are recognized by a pressure vessel research institution and referenced in the design. In the conventional finite element calculation, users can, at the same time, obtain the J- integral of the component with crack. So the method in the paper has strong practicability and high engineering application value.

Prototype observation and finite element analysis were carried out on a weld seam between a spiral case and a penstock of #6 generator in a certain power plant. According to the observation data and finite element calculated results, deformation and stress were analyzed for the weld seam in continuous operating stage (power generation, EL. 206.00). The results show that in the normal operation power generation stage, the strengths of the penstock, the spiral case and the weld seam are all satisfied; Even if the inlet water level reaches to EL. 275.00, the three parts are all safe (when the residual stress isn’t considered, the stress is far lower than the strength allowed values). However, the stress at point E is obviously higher, it is necessary to make further testing inspection. Finally the following suggestions are given: (1) the strain gauges should be arranged both circumferentially and axially, this is because the circumferential stress of weld seam is greater than axial stress; (2) the stiffener rings should be moved left by 50mm, thus the axial stress can be minimized and the circumferential stress can also be reduced.