| Firstly, the strength of rotator is analyzed by finite element method under theinternal pressure based on the summary and analysis of the rotator structural strengthand the fracture mechanics research at home and abroad. Because of the complex shapeand large size, the rotator is analyzed by establishing an axisymmetric model whichignoring the threads connection between the cylinder and the base. It can be done basedon Saint-Venant principle to build axisymmetric finite element model and thethree-dimension sub-models of both the equidistant straight threads and the spiral onewith a thread angle. The effects of the material nonlinearity and the contact nonlinearityon the container should be taken into account. And the cutting boundary displacementof the overall model which is axial symmetry is used as the boundary displacement ofthe three-dimension sub-models. The comparative analyses of the results of theircalculating stress distribution should be made in detail in order to get a more accuratestress distribution at the threads connection.Secondly, the strength of rotator is analyzed at the maximum air pressure,especially the threads strength. The rotator is subject to various loads when it moves inthe chamber. Because of that, its parts will occur in varying degrees of deformation. Thedeformations will affect the correct movement of rotator in the chamber, or prevent themovement. The axisymmetric finite element model without the threads connection isestablished and calculated after the current acceleration is calculated by the inertia reliefmethod. The finite element sub-model of both the equidistant straight threads and thespiral threads are calculated to get more accurate stress results. The results are analyzedand compared in order to provide a theoretical basis for enhancement of the rotatorstrength.Thirdly, the rotator is explored by numerical simulation method in the process ofsqueezing. The process of rotator squeezed into the cylinder bore is simulated by ANSYS/LS-DYNA. The process of finite element calculation is controlled by ALEalgorithm, which considering the strain impact rate of plastic material models anddisplacing the rotator motion of load simulation with the forced displacement. Thismethod can be widely used in the numerical simulation of actual structure in the processof squeezing, and provided reference for its research.Finally, the cylinder ruptures of rotator in the internal pressure test are analyzed byfinite element method. Its two-dimensional finite element model included the crackle isestablished. The value of the stress intensity factor is calculated and the effects of someother factors like crackle depth, crackle length, internal pressure are researched based onstatic analyses. The relational equation of the stress intensity factor and the internalpressure is worked out, and it can be used in calculating the limit value of internalpressure. |
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