船舶轴系扭振计算和测试实例分析

船级社规范对轴系扭振提出了计算和实测的要求。本文对若干轴系固有频率的实测值与计算值不一致的船舶进行了分析，并给出了对影响其相应计算精度的减振器、曲轴、联轴节刚度等扭振参数进行了修正的实例；通过实测，对无阻尼自由振动计算的振型精度亦进行了分析，按振型推算系统响应超规范要求的船舶，可根据实测振幅来调整阻尼参数并用解析计算法来评价轴系扭振特性。结果表明，精确测定出系统的固有频率和振幅，从而核定轴系的扭振参数，是提高扭振计算精度的关键所在。

Torsion Vibration Calculation of Ship Shafting and Its Text Example Analysis

The CCS Rules require that calculation and test of torsion vibration of ship shafting shall be made. In this paper, the ships that the measured results of their shafting natural frequency are different from the calculated ones are analyzed, and some examples, in which torsion vibration parameters of damper, stiffness of crankshaft and coupling are corrected relatively to their calculation accuracy, are presented. Through tests, vibration mode accuracy of non damping free vibration calculation is analyzed. For the ships that their shafting response calculated with the vibration mode is beyond the requirements of the Rules, damping parameters are adjusted based on the measured amplitude, and an analytic calculation method is used to evaluate shafting torsion vibration characteristics. Results show that to measure natural frequency and amplitude with high accuracy and thereby to check and ratify shafting torsion vibration parameters is the key to improve calculation precision of torsion vibration.