中文摘要：

将计算单裂纹结构基频的方法推广到求含多处裂纹梁弯曲振动的近似基频。通过在未损伤梁位移的基础上叠加一个多项式来构造裂纹梁的位移函数，它满足梁的边界条件和运动条件；应用Rayleigh方法，求出含多处裂纹简支梁的弯曲振动基频，得到了梁的近似基频的闭式表达式。与Ansys计算结果比较表明，该方法具有较高的精度。

英文摘要：

An approximate method of calculating the fundamental frequency of bending vibrations of multi-cracked beams is proposed on the basis of a modification of the method for single-cracked structures. The deflection of multi-cracked beams is assumed by adding polynomial functions to that of the uncracked beams. This new deflection function satisfies the boundary and the kinematic conditions. The closed-form expressions for the fundamental frequency are obtained by using the Rayleigh method. Its validity is confirmed by comparison with Ansys simulation results.