被动约束层阻尼梁动力学优化研究

研究被动约束层阻尼(passive constrained layer damping,PCLD)梁的动力学优化问题,优化变量为PCLD的起始位置、覆盖长度、阻尼层厚度和约束层厚度。在局部覆盖PCLD梁动力学特性的传递函数解的基础上,建立PCLD梁的单目标和多目标优化模型。单目标优化中以结构模态损耗因子最大为优化目标,讨论约束条件中PCLD附加结构质量系数对优化结果的影响。多目标优化中以各阶模态损耗因子最大、各阶固有频率改变量最小和PCLD附加的结构质量最小为优化目标,增加约束层纵振频率的约束条件,讨论优化目标函数中各权重系数对优化结果的影响。此外,还在有限元软件MSC.Patran/Nastran中二次开发出PCLD梁动力学优化模块。两种方法的优化结果一致,验证本文计算结果的正确性。

OPTIMIZATION OF DYNAMICS FOR BEAM WITH PASSIVE CONSTRAINED LAYER DAMPING

A study on optimal placement and design parameters of passive constrained layer damping(PCLD) treatment for vibration suppression of beam was presented,and the PCLD start placement,PCLD length,constrained layer thickness and viscoelastic layer thickness were chosen as design variables.Based on the dynamic characteristic of beam with partial PCLD treatment by the distributed parameter transfer function method(TFM),optimization models of single-objective and multi-objective were established for PCLD beam.In single-objective optimization,the aim was to maximize each mode loss factor.The effects of PCLD attached mass modulus on optimal results were discussed,which was in constraint functions.In multi-objective optimization,the aims were to maximize each mode loss factor,to minimize each frequency’s shift and to minimize the PCLD attached mass.The restriction condition of constraining layer’s longitudinal frequency was proposed,and the effects of weighting factors in objective function were also discussed.Moreover,a dynamic optimization module was developed in finite element method software MSC.Patran/Nastran.Numerical predictions of two methods agree well,and demonstrate the effectiveness of the methods and the programs.