Multi-wedge synchronous rolling by cross-wedge rolling is one of the most advanced methods that can form rolling railway axis. Its rolling quality mainly lies on inner transversal stress and shearing stress of rolling workpiece. In this paper, based on the rotated theory of multi-wedge rolling, through using Ansys/Ls-Dyna FEM software, multi-wedge synchronous rolling railway axis by cross-wedge rolling is simulated. It has been systemically researched that technical parameters effect transversal stress and shearing stress. In the meantime, the calculating model is verified by experiment. Through this study, It is obtained that the law of technical parameters effect on rolling railway axis by multi-wedge synchronous cross-wedge rolling. These research conclusions can provide scientific basis for rolling railway axis by multi-wedge synchronous cross-wedge rolling and rolling better quality.

It is quite difficult for reservoir exploitation with worse barrier zone, especially in thin pay-zone, limiting hydraulic fracture height propagation. This paper described the theory of controlling the fracture height by creating artificial barrier, and net pressure distribution in the crack was determined by assuming the artificial barrier is with stress gradient. Then, stress intensity factors in the crack tip were gotten on the basis of fracture mechanics theory, and fracture propagation model was established in accordance with fracture criteria of tensile open crack. The established model also described the action of treatment pressure on the fracture height and influence of artificial barrier on the fracture height propagation. By contrasting the results, it is feasible for artificial barrier to limit the fracture height propagation, and this model also can be used in hydraulic fracturing design in the oilfield.

The broadening stage is the main stage in Multi-wedge Synchrostep Rolling railway axle by Cross-wedge Rolling. Based on the rotated theory of Multi-wedge Rolling, through using Ansys/Ls-Dyna FEM software, This paper provides a systematic analysis of the stress-strain in the broadening stage of Multi-wedge Synchrostep Rolling railway axle by Cross-wedge Rolling. Through this study, it is obtained the stress-strain distribution and evolution on Multi-wedge Synchrostep Rolling railway axle by Cross-wedge Rolling. These research conclusions can provide scientific basis for Multi-wedge Synchrostep Rolling railway axle by Cross-wedge Rolling.