Abstract: Modal analysis is the foundation of dynamic analysis. The finite element method is analyzed by using ANSYS software taking truss structure as a example. It would provide modal parameter like natural frequency, and we can get a better design according to the parameter, like  enhancing the rigidity of truss structure and improve the natural frequency to avoid resonating.

Key words: Modal analysis, Natural frequency, Truss structruc ture, Mode of vibration, Finite element method