含损伤黏弹性阻尼加筋层合板声功率和指向性变异

Variations of sound radiation power and directivity of stiffened laminated panel with viscoelastic damping material

该文旨在研究损伤位置和程度对自由阻尼加筋层合板声辐射功率和指向性的影响。基于Mindlin和Timoshenko梁理论,建立了自由阻尼层合板-梁组合结构有限元模型。数值求解四边简支边界条件自由阻尼加筋层合板振动响应,继而通过Rayleigh积分计算加筋层合板辐射声功率和指向性。将计算得到的前4阶模态固有频率、声辐射功率与指向性与已有文献进行了对比基本一致,验证了数值模型的正确性。最后,详细讨论了损伤位置和程度对自由阻尼加筋层合板固有频率、振型、声辐射功率和指向性的影响,结果表明:随着结构损伤程度的增大,声辐射功率峰值向低频移动,在更多角度上出现明显的指向性;声辐射功率和指向性对损伤位置比损伤程度更加敏感。

This paper is to study the effects of damage location and degree on acoustic radiation power and directivity of an unconstrained damping stiffened laminated plate.Based on Mindlin and Timoshenko beam theory,a finite element model is established for laminated plate consisted of beams structure.The vibration response of the stiffened laminated plate solved numerically with full edges simply supported.Then,the sound power and directivity of the stiffened aminated plate are calculated according to Rayleigh integral.The first five modal frequencies,acoustic radiation power and directivity are basically consistent with the existing literature,which verifies the correctness of the numerical model.Finally,the effects of damage location and degree on the natural frequency,modal shape,acoustic radiation power and directivity of the stiffened laminated plates are discussed in detail.The results show that the peak values of acoustic power move to low frequency with the increasing of structural damage degree and obvious directivity at more angles.The acoustic radiation power and directivity are more sensitive to damage location than damage degree.