淬火应力场对铝合金厚板固有频率的影响

Influence of Quenching Stress Field on Natural Frequency of Aluminum Alloy Thick Plate

建立7075铝合金厚板淬火残余应力场数学模型,理论与实验探讨振动时效中淬火残余应力场对板固有频率的影响。结果表明,板尺寸、密度、均匀性等物理材料特性确定时,其固有频率主要受到残余应力场的分布状态影响,且高阶固有频率受残余应力的影响比低阶固有频率大。淬火残余应力场总是增大板的固有频率,振动时效消减或均匀化残余应力的同时,也将降低各阶次固有频率。

Mathematical model of quenching residual stress filed of 7075 aluminum alloy thick plate was established to theoretically and experimentally analyze the influences of quenching residual stress on plate natural frequency during VSR. The results show that plate natural frequency, based on constant physical material characteristics like dimension, density and homogeneity, etc. , is mainly influenced by the residual stress distribution characteristics while quenching residual stress always increases plate natural frequency. And the higher the rank number is, the larger the influence of residual stress on frequency is. Moreover, natural frequency in each order would decrease following residual stress relaxation or homogenization caused by stress re-distribution during VSR.