曲軸磨床雙樑結構模型動態分析

Dynamic Analysis for the Crankshaft Grinder with Dual Beam Structure

查國強(K. C. Cha) ； 王能治(N. Z. Wang) ； 廖建義(J. Y. Liao)

《中華民國振動與噪音工程學會論文集》 2014 (2014/06) Pp. 56-61

摘要

本文研究曲軸磨床中具自由雙樑結構模型的動態特性分析，以Lagrange能量法結合假設模態展開（Assumed mode expansion）為基礎，建立逐步將系統中雙樑與其它集中質量或彈簧等元件堆疊之積木法（Building block approach）觀念，推導出系統動力方程式。文中首先以系統中雙自由樑分別僅以平移與旋轉兩個剛體模態合成之假設模態展開法與七個自由度集中質量參數模型比較，驗證結果一致後，再將此假設模態法中加入彈性模態模擬雙樑與剛體模型比較其動態特性差異，使分析更真實與可靠。分析結果顯示：以結構穩定指標MNRPODC評估，剛體模型較彈性雙樑模型高估約8.5倍。

關鍵字

曲軸磨床 ； 假設模態展開 ； 積木法 ； 整機結構動柔度最大負實部

並列摘要

The analysis of the dynamic characteristics of the free-free double-beam structure of a crankshaft grinding machine is presented. By combining the Lagrange energy method with the technique of assumed mode expansion as the basis, the system dynamic equations are derived through the building block approach with the double-beam as main parts and other accessory components, analogous to lumped masses or springs in the system. Initially, the technique of assumed mode expansion is compared to the lumped mass parameter model with 7 degrees of freedom (DOF) where the assumed mode expansion method for the free-free double-beam is synthesized by two rigid body modes of translation and rotation. After the results of rigid models are verified, elastic modes are incorporated into the assumed model method for simulation so as to compare the dynamic characteristics between the models of the double-beam and the rigid body, to make the analysis more realistic and reliable. It shows that he structural stability performance index of the rigid model overestimates the elastic double-beam model about 8.5 times.

並列關鍵字

The Crankshaft Grinder ； The Assumed Mode Expansion ； Building Block Approach ； Maximum Negative Real Part of the Overall Dynamic Compliance