Papers by Author: Jian Hua Wu

Abstract: Three turbulent models, standard k- model, realizable k- model and SST k- model, are proposed to calculate the distribution of the flow field in a novel static circulating jet mixer. The results show that the SST k-model can depict truly the fluid motion in the novel jet mixer from the velocity vector distribution. The k-Standard model overestimates k in the wall and the bulk zones. Comparing the numerical models, the SST k- model gives better results than the other k-models at the same Reynold number.

Abstract: A series of low-cycle fatigue experiments of axial-torsional loading of variable amplitudes were performed on the tubular specimens of 304 stainless steel. Two models of multiaxial low-cycle fatigue life, KBM and FS method, are evaluated based on the fatigue life data of 304 stainless steel. Rainflow cycle counting and the Liner Damage Rule are used to calculate fatigue damage. It was shown that the part prediction results are nonconservative for the two models. The life prediction is done again based on the weight function critical plane method for the two models. The prediction results are better by using the weight function critical plane method than the previous results for KBM model. But the prediction results are improved little for FS model in spite of the weight function critical plane method being used.

Abstract: Fatigue tests are conducted on 304 stainless steel and 45C steel under fully reversed strain control conditions with two different loading modes. 45C steel exhibits cyclic softening under each phase loading. While for 304 stainless steel, much additional hardening is observed in out-of-phase loading. The damage values for failure of 45C steel is similar to the previous research, however, 304 stainless steel is not. Fatigue life is predicted based on the linear damage rule, the double linear damage rule, and the plastic work model of Morrow. The damage value is different in the same loading mode for the two materials according to linear damage rule.