中文说明：模态是结构的固有振动特性，每一个模态具有特定的固有频率、阻尼比和模态振型。这些模态参数可以由计算或试验分析取得，这样一个计算或试验分析过程称为模态分析。这个分析过程如果是由有限元计算的方法取得的，
English Description：
Modal structure of natural vibration characteristics of each mode has a specific natural frequency, damping and mode shape. These model parameters can be calculated by analysis or test, such a calculation or test process called modal analysis. If this analysis process is made by the finite element method,