PVDF声辐射模态传感器设计中的关键问题研究

利用分布式位移传感材料PVDF薄膜设计声辐射模态传感器,通过检测低阶辐射模态的幅度以获得结构近似的辐射声功率。基于声辐射模态理论和PVDF传感模型,推导了PVDF形状系数理论公式,对设计中的关键问题进行了研究,得出PVDF的形状系数和结构振动模态选取的通用准则,提出分频段设计法解决了形状系数和结构振动模态之间在选取上的矛盾,在此基础上对PVDF传感器进行了优化设计并给出了PVDF对的中心线取值的一般规律,利用声辐射模态的嵌套特性使得输出电荷的放大倍数与频率呈线性关系,并通过实例仿真验证了文中结论。

On Improving the Method for Designing Acoustic Radiation Mode Sensor Using PVDF Films

Polyvinylidene fluoride(PVDF) sensors can be used to obtain the approximated radiated sound power of the vibrating structure.In designing this kind of sensors,it is difficult but important to choose the maximum order of shape coefficients and the order of the structural modes,and to determine the location of the center line for placing the PVDF pairs.In this paper,we present an improved method for solving these key issues in designing such sensors.The formulas for the shape coefficient of the PVDF pairs are derived based on the acoustic radiation modes and a PVDF sensing model.By combining structural modes and acoustic radiation modes,the rule to choose the maximum order of shape coefficients is given according to the chosen order of the structural modes,and a new approach of designing PVDF pairs in partitioned frequency band is presented to resolve the conflict in the choosing process.Finally,the optimized design approach and the criterion for determining the location of the center line for placing the PVDF pairs is given.According to the "nest property" of radiation modes,the amplificatory multiple of total charge response of the PVDF pair becomes linear to the exciting frequency.A number of computer simulations have been performed to demonstrate the above-mentioned conclusions.