The second vibration mode of natural frequencies of variable crosssection towers are calculated by means of ANSYS finite element program, the simplified calculating formula of which is provided.

• 本论文用大型有限元软件ANSYS计算变截面塔的二阶自振频率。通过对大量的塔进行计算，提出了计算三段变截面塔二阶自振频率的简化公式。