Jia Fang

Speedy Stiffness modeling and designing of plane supporting spring

Electronic instruments for aeronautics and astronautics usually endure stronger impact or vibration under hostile environments, which results in the storage of more deformation energy within the isolators. Another necessary requirement comes from the limitation of the assembly space where the larger isolator is unallowable. Compared with other commonly used vibration isolators, a plane supporting spring is characterized by its greater deformation energy, lower stiffness, better static and dynamic characteristics. However; there exist some difficulties in modeling and designing the plane supporting spring. To solve the problems, a speedy modeling program of APDL (ANSYS Parameter Design Language) based on FEA software ANSYS is developed, which can rapidly establish a series of FEM analytical models of plane supporting spring with single or several spiral lines. Furthermore, the differences of the stiffness in each direction of plane supporting spring are analyzed on the basis of rapid modeling. In particular; axial stiffness and radius stiffness, especially the influencing factors of radius stiffness, are studied carefully. And finally, different spring assembly effects on radius stiffness are deeply explored.

A study on dynamic errors of high speed pressd mechanism with clearance

The present paper focuses upon the dynamic errors of high speed press mechanism with clearance. Based on a continuous contact model, the clearance at joint is treated as a rigid linkage, whose length equals the radial clearance and has no mass. The dynamic equation for high speed press is developed via the kinetics universal equation. By comparison of the results between the computer simulation and experimentation computer simulation, clearance and its size as well as the spinning speed of crank are further analyzed concerning the impacts on both the output error and the kinetic responses of high speed press. The investigation is of great significance to the accuracy design of high speed press.

Modeling and optimization for circumferential uniformity of MOCVD showerhead hole arrangement

This paper presents a method for modeling and analyzing the circumferential uniformity of MOCVD showerhead hole arrangement. The coordinate expressions of MOCVD showerhead hole are derived from the initial position of the radial hole on the helix curve. Through rotating the strip observation window around the center of the showerhead face plate at an equal angle, a data set is obtained by computing the total area of holes in the strip observation window. The circumferential uniformity of hole layout is measured according to the standard deviation of this dataset, and then an optimal layout model of the holes is established. The result indicates that the sampling rotating angle has limited impact on the ultimate hole arrangement, which verifies the robustness of the proposed method. Finally, optimal parameter of the helix curve is built using the genetic algorithm (GA), and the optimal layout of showerhead holes is illustrated correspondingly.