The residual stress distribution was studied by an analytical model, due to shot peening on the welding carbon steel surface layer. The initial welding residual stresses before shot peening were taken into considerati...The residual stress distribution was studied by an analytical model, due to shot peening on the welding carbon steel surface layer. The initial welding residual stresses before shot peening were taken into consideration in this analytical model. The Hertzian elastic contact theory was used to get the elastic compression stress state after impact on the surface layer. The initial welding stress field and the shot peening stress field would superpose and the welding surface layer would yield based on the elastic-plastic evaluation, then the residual stress after shot peening can be achieved. The influence of initial welding residual stress on the stress distribution after shot peening was analyzed and discussed. A series of experiments were carried out and the residual stress on the welding surface was determined by X-ray diffractometer before and after shot peening. The calculation results of the analytical model are consistent with the experimental results. The critical shot velocities when welding surface layer yielded and reverse yielded were calculated. While the welded joint surface material reversely yielded, the maximum compressive residual stress would not obviously increase with the increase of shot velocity, the thickness of the compressive stress layer would be increased. Welding residual tensile stress can enlarge the thickness of the compressive stress layer at the same shot velocity when reverse yield appeared.展开更多
This paper presents the stress incremental rate of each element by using finite element numerical simulation way.Combined with the practical continent boundary condition and medium parameters, this paper applies the s...This paper presents the stress incremental rate of each element by using finite element numerical simulation way.Combined with the practical continent boundary condition and medium parameters, this paper applies the stress increment rate to the more practical modified cell automaton model according to the cell automaton principle. The paper preliminarily gives the more practical seismic space-time repeated evolutive maps, and compares the imitative seismic energy release with the real seismic energy release. It is thought that this model has its advantageover the old one whether in the seismic imitative characteristics or in the comparison with the realsituation and is more practical model.展开更多
基金Funded by the Fundamental Research Funds for the Central Universities(51271014)
文摘The residual stress distribution was studied by an analytical model, due to shot peening on the welding carbon steel surface layer. The initial welding residual stresses before shot peening were taken into consideration in this analytical model. The Hertzian elastic contact theory was used to get the elastic compression stress state after impact on the surface layer. The initial welding stress field and the shot peening stress field would superpose and the welding surface layer would yield based on the elastic-plastic evaluation, then the residual stress after shot peening can be achieved. The influence of initial welding residual stress on the stress distribution after shot peening was analyzed and discussed. A series of experiments were carried out and the residual stress on the welding surface was determined by X-ray diffractometer before and after shot peening. The calculation results of the analytical model are consistent with the experimental results. The critical shot velocities when welding surface layer yielded and reverse yielded were calculated. While the welded joint surface material reversely yielded, the maximum compressive residual stress would not obviously increase with the increase of shot velocity, the thickness of the compressive stress layer would be increased. Welding residual tensile stress can enlarge the thickness of the compressive stress layer at the same shot velocity when reverse yield appeared.
文摘This paper presents the stress incremental rate of each element by using finite element numerical simulation way.Combined with the practical continent boundary condition and medium parameters, this paper applies the stress increment rate to the more practical modified cell automaton model according to the cell automaton principle. The paper preliminarily gives the more practical seismic space-time repeated evolutive maps, and compares the imitative seismic energy release with the real seismic energy release. It is thought that this model has its advantageover the old one whether in the seismic imitative characteristics or in the comparison with the realsituation and is more practical model.
