Dynamic Modeling And Analysis Of Statically Indeterminate Supported Optical Platform Based On Finite Element

In a large-scale optical system, high-power laser element and optical transferring system are usually integrated on an optical platform. The platform must have sufficient dynamic stability and can also isolate the environmental vibration from spreading upward. The currently used platform is usually hyper-statically supported, and its damping capacity can be improved by increasing its weight then its maneuvering ability is severely decreased in the same time. So it’s required to carry out light weight design for the platform by creating high precision dynamic model for the platform and carrying out dynamic analysis and optimization.In this paper, a hyper-statically supported optical platform was investigated as the main subject on which FEM (Finite Element Method) simulation and laboratory experiment were carried out and the data were compared. The usually used FEM modeling method was insufficient, so the committed steps was evaluated and settled, by which a high precision and high reliable simulating method was setup. Main works were listed as follows:On the first, we deduced the platform’s structural dynamic equation based on the FEM theory. In this process, we studied and compared the basic theories used for dynamic equation solution, which includes modal analysis theory, multi-dimensional linear system’s dynamic response solving theory based on modes superposition theory.Secondly, we built a dynamic FEM model and carried out some experiments based on a simulated optical platform attending to settle two key questions, which included the element type’s selection and the bolt fastening structure’s management. The researching results indicated that such methods have high degree of accuracy which included solid volume element modeling, bolt modeling, hybrid element type modeling, and bolt fastened position’s local nodes coupling, but the hybrid element type modeling method has highly solving efficiency. According to previous conclusions, we suggest that different element types should be used to modeling different structure style, the obtained FEM model can yield high solving precision, low solving workload, and high efficiency.Lastly, by using hybrid element modeling method and local nodes coupling method, a hyper-statically supported optical platform was studied which was used to support the optical resonant cavity, of which the dynamic performance was evaluated and predicted, on whom field experiment was carried out. By comparing the simulated and experimented data, we could see they were highly agreed, which declared the dynamic modeling method used in this paper had outstanding reliability and availability.