大型船用螺旋桨加工机床模态分析及螺旋桨叶片加工优化-机械电子工程专业论文.docxVIP

华 华 中 科 技 大 学 硕 士 学 位 论 文 II II Abstract Large marine propeller blades are large thin-walled surface with irregular shape, and deform easily when under the cutting force. In order to improve the processing quality and machining efficiency, the modal frequencies and mode shapes of seven-five axis CNC lathe milling machine tool machining propeller, clamping support positions distribution and the selection of the cutting parameters were studied in this paper. In order to avoid vibration occured in the seven-five axis machine during processing and improve the processing quality, the modal analysis of the machine was carried out to obtain the machines natural frequencies and shapes. The results of theoretical modal analysis and experimental modal analysis were compared to prove the correctness of theoretical modal analysis results. Display body constraint was applied to the machine table. The results of the modal analysis of machine with table in elastomer and display body were compared in accuracy and computational efficiency. It could be proved the machine with table in display body has the same accuracy and better computational efficiency. Propeller blades were deformed easily under the cutting force, for this problem, clamping support optimization procedure based on genetic algorithm was developed. The ANSYS software was used to compute the deformation. By using the ANSYS parametric programming language (APDL) the optimization procedure could run automaticlly, which simplified the operation process and improved the optimization efficiency. For the processing efficiency of propeller, cutting parameters optimization program based on genetic algorithm was developed in this paper. The independent variables of the optimization program were cutting depth, cutting width, and feed rate. The objective function was material removal rate. Through the computation of the program, the best material removal rate could be got, when the deformations of the loading points were less t