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，则称为计算模态分析；如果通过试验将采集的系统输入与输出信号经过参数识别获得模态参数，称为试验模态分析。通常，模态分析都是指试验模态分析。振动模态是弹性结构的固有的、整体的特性。如果通过模态分析方法搞清楚了结构物在某一易受影响的频率范围内各阶主要模态的特性，就可能预言结构在此频段内在外部或内部各种振源作用下实际振动响应。因此，模态分析是结构动态设计及设备的故障诊断的重要方法。
English Description：
Modes are the natural vibration characteristics of structures, and each mode has a specific natural frequency, damping ratio and mode shape. These modal parameters can be obtained by calculation or experimental analysis, such a calculation or experimental analysis process is called modal analysis. If the analysis process is obtained by the finite element calculation method, it is called computational modal analysis; if the modal parameters are obtained by identifying the input and output signals of the system through the test, it is called experimental modal analysis. Generally, modal analysis refers to experimental modal analysis. Vibration mode is the inherent and integral characteristic of elastic structure. If the characteristics of the main modes of the structure in a certain frequency range are understood by modal analysis method, the actual vibration response of the structure under the action of various external or internal vibration sources in this frequency band may be predicted. Therefore, modal analysis is an important method for structural dynamic design and equipment fault diagnosis.