强冲击压电陶瓷结构的应力波传播及电压输出特性

Propagation of Stress Wave and Characteristics of Voltage Output During Strong Shock Piezoelectric Ceramic Structure

为了研究强冲击作用下应力波在压电陶瓷复合结构(前基板-压电陶瓷-后基板)中的传播规律和压电陶瓷的电压输出特性,利用自行构建的聚偏氟乙烯(PVDF)冲击压力测试系统和压电陶瓷的电压输出测试系统并结合一级轻气炮加载系统,开展了2A12柱状铝弹丸分别以313m/s、326m/s、379m/s和397m/s的速度正碰撞压电陶瓷复合结构(不同材料的后基板)实验,采集压电陶瓷与后基板间压力传感器产生的电压信号和压电陶瓷的电压输出信号.同时,基于一维弹性波的传播理论,推导了应力波在弹体与压电陶瓷复合结构接触界面所形成的变截面问题中传播时的碰撞速度与压力峰值的计算关系式,得到了不同碰撞速度条件下压电陶瓷后表面处的应力峰值;利用压电陶瓷输出电压与冲击压力峰值间的理论计算关系式并结合Matlab编程对冲击压力的实验数据处理所得到的冲击压力峰值,计算得到了压电陶瓷的电压输出峰值.研究结果表明:通过理论计算得到的冲击压力峰值、电压输出峰值与实验测量所得结果均基本吻合;在碰撞速度接近时,后基板的材料性质(有机玻璃和铝合金)对应力脉冲峰值特征的影响显著,有机玻璃作为后基板的应力脉冲峰值高于后基板为铝合金时的应力脉冲峰值,且有机玻璃作为后基板的脉冲持续时间长于后基板为铝合金时的脉冲持续时间;压电陶瓷的电压输出峰值随冲击压力峰值的增加而增大且二者呈非线性关系.

In order to research the propagating rules of stress wave in piezoelectric ceramic composite structure（ front substrate-piezoelectric ceramic-rear substrate） and characteristics of the output voltage for piezoelectric ceramics under strong shock loading. The Polyvinylidene Fluoride（ PVDF） pressure test system, the output voltage test system and the onestage light gas gun loading system were built by ourselves and used in the laboratory. Experiments were carried out by 2 A12 aluminum cylindrical projectile at the velocities of 313 m/s, 326 m/s, 379 m/s and 397 m/s, respectively, against piezoelectric ceramic composite structures（ rear substrates of different materials）. The voltage signal generated by the PVDF pressure sensor between the piezoelectric ceramic and the rear substrate and the voltage output signal of the piezoelectric ceramic were collected. At the same time,based on the propagating theory of one-dimensional elastic wave, the relationship between the collision velocity and the pressure peak of the stress wave in the variable cross-section problem formed by the contact between the projectile and the piezoelectric ceramic composite structure is deduced. The stress peaks at the rear surface of the piezoelectric ceramic were obtained at different collision speeds based on the relationship deduced. The peaks of the voltage output for the piezoelectric ceramics are calculated by the theoretical relationship between the peak of output voltage for piezoelectric ceramic and the peak value of the impact pressure. The peak value of the shock pressure is obtained by the experimental data processing from the voltage signals measured programmed by Matlab. The results show that the peak values of the impulse pressure and the voltage output are basically consistent with the experimental results. When the impact speed is close, the material properties（ plexiglas and aluminum alloy） of the rear substrate have a significant effect on the peak value of the stress pulse. The peak value of the stress pulse of the plexiglass as the rear substrate is higher than the peak value of the pulse stress when the rear substrate is an aluminum alloy. And the pulse duration of the plexiglass as the rear substrate is longer than the duration of the pulse when the rear substrate is an aluminum alloy. The peak value of the voltage output of the piezoelectric ceramic increases with the increase of the impulse pressure and it is non-linear.