高温下含裂纹铝合金梁自由振动频率分析

针对高温下含裂纹梁损伤振动的研究中不考虑温度对材料性能的影响等不足,分析了含裂纹简支梁的振动频率随温度的变化趋势,建立了高温下含裂纹简支梁的振动频率方程,并对高温下含裂纹简支铝合金梁进行了数值模拟运算,分析了其振动频率随温度的变化情况,给出了高温下含裂纹铝合金简支梁的振动频率与弹性模量的关系式.分析结果表明:温度的升高导致了材料弹性模量的下降,而弹性模量的下降又导致了梁自振频率的降低,随着温度的升高,裂纹的相对深度越大,梁自振频率下降幅度越大；裂纹位置离支座越近,对梁自振频率的变化影响越小.

Free vibration frequency variation analysis of a cracked aluminum alloy beam under high temperatures

A beam working in a high temperature environment often displays crack damage which could cause changes in the local stiffness of the structure.Therefore,it must produce a certain effect on the dynamic characteristics of the structural vibration system,leading to the reduction of natural frequencies.However,the cracks in high temperatures would not only lead to a change in the inherent frequencies of the structural vibration system,the rise in temperature could also lead to the elastic modulus of materials being decreased which in turn could lead to the reduction of structural vibration frequencies.In this paper,the variations of vibration frequencies of a cracked aluminum alloy beam in high temperatures were analyzed and the frequency equations were established.In the numerical simulation computation,the rule concerning changes in the vibration frequencies with the temperature was discussed and the relational expression of vibration frequencies and the elastic modulus of the cracked aluminum alloy beam under the high temperatures were given.