涡轮叶片模态实测阻尼比的有限元应用

Application of damping ratio for turbine blades by modal testingon finite element analysis

为了更加精确地通过有限元来模拟涡轮叶片的谐响应特性,剖析了有限元分析中阻尼矩阵的构建方法,并且选定了适用于真实涡轮叶片设计的阻尼矩阵模型.在进行涡轮叶片有限元谐响应计算时,以模态测试得的阻尼比为基本参数,建立构建阻尼矩阵的方法,该方法能处理具有单独共振频率或具有临近共振频率的振动问题.通过模拟涡轮叶片的响应试验,测得了试验系统的阻尼比及模拟涡轮叶片的位移响应.根据测得的系统阻尼比,运用构建阻尼矩阵的方法,对具有单独共振频率特征的模拟涡轮叶片进行了谐响应计算,结果显示模拟涡轮叶片的位移响应与试验结果基本一致.运用该方法进行涡轮叶片的谐响应分析可比较精确地得到其谐响应特性.

For more accurately imitating turbine blade＇s harmonic response characteristic by using finite element method, studied how to genetate damping matrix on finite element analysis, and selected a damping matrix model which was suitable for the design of real turbine blades. In the finite element harmonic response analysis of turbine blade, a method forgenerating damping matrix was made on the basis of the damping ratio which was measured in modal testing. The method can be used for any individual resonance frequency problem orcoupling resonance frequency problem. After imitated turbine blade＇s response experimentation, system damping ratio and imitated turbine blade＇s displacement response was meas-ured. According to the system damping ratio and the method, analyzed imitated turbine blade＇s harmonic response which had individual resonance frequency. The analysis result in-dicate that the imitated turbine blade＇s response is approximately consonant with the experimental result. So it is accurate that using the method to analyze harmonic response of turbineblade.