The Same Twin-screw Stress Analysis And Finite Element Simulation

A lot of accomplishments have been achieved since the numerical calculation was used in the research for new kind of twin-screw elements. However, this way was usually used in the analysis of the fluid field in the twin-screw. In this thesis, the stress that the shafts and the screws are bearing is analyzed by means of the numerical calculation with the help of ANSYS software, and then both the shafts and the screws structures are improved.Several kinds of shafts are involved in the work and the stress that they bear is analyzed. Hexagonal shaft shows the best resistance capability to the pressure among the mentioned shafts. And involute-spline shaft's capability to resist the pressure is next to. The shaft with flat key is worse. The local structures where the stress is abrupt are modified to optimize the shafts. And some rational suggests about how to reduce the stress concentrating are put forward to.The fluid field of a section twin screw is analyzed through solid modeling and the twin screws' real boundary condition simulating. The distribution of pressure in the fluid field is found: The pressure of this section fluid field rises gradually from entrance to the exit, and the pressure values on the both sides of the ridge are different. It is along flight direction, not axes direction that the pressure is formed steadily. Three kinds of screw elements are analyzed. Among which, the stress in the rectangle-groove screw is the highest, the stress in the trapeziform groove screw is lower than it, and the conjugate groove screw shows the best capability to resist the pressure. The trapeziform angle is modified during the calculation and analysis, then the relation between the trapeziform angle, output and the maximal stress has been found. And the new viewpoints of design new screw element are represented sequently.In this thesis, I try to find a reasonable way with the help of finite element analysis method to acquire new screw element for high extrusion output, while the shafts and the element will be safety under the pressure. And further more, the optimization for the design of shaft and twin-screw element will be achieved in futhure.