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对高功率超声脉冲作用下金属板中的超谐波、次谐波、准次谐波以及混沌等非线性振动现象进行了实验和理论研究.在实验中,高功率超声换能器产生脉冲调制的高频振动激励金属板产生非线性振动,利用激光测振技术测量不同尺寸和不同固定方式下金属板复杂的非线性振动情况,并对其进行了时序分析、频谱分析以及相空间分析.根据实验条件,提出包含非线性接触阻尼的振动-碰撞动力学模型,用以研究强超声振动-碰撞作用下的板非线性振动机制,并进行了相应的理论计算.计算结果表明,超声换能器的变幅杆与金属板之间的间歇性高频碰撞作用是金属板强非线性振
关键词:
非线性板振动
强超声脉冲激发
振动-碰撞动力学 相似文献
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对夹心式径向复合压电换能器径向振动特性进行了研究。该换能器由弹性内芯、预应力金属管及柱面压电陶瓷晶堆径向复合而成.利用机电类比法,得到了换能器的径向振动等效电路及频率方程。探讨了换能器第1、2阶径向共振频率及有效机电耦合系数与其几何尺寸的关系。研究表明,换能器第1阶径向共振频率随其内芯内径及预应力管壁厚度增大而降低;第2阶共振频率随内芯内径增大存在极小值,但随预应力管壁厚度增大单调下降。此外,采用第2阶径向共振模式能获得较高的有效机电耦合系数,并且压电陶瓷处于位移节线时,换能器有效机电耦合系数达极大值。对换能器共振频率的测试与有限元仿真表明。理论与实验及仿真结果符合较好。 相似文献
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强超声脉冲激励下金属板超谐波和次谐波振动的有限元分析 总被引:1,自引:0,他引:1
针对实验中观察到金属板在强超声脉冲作用下的超谐波和次谐波振动现象,采用显式有限元方法建立有限元模型,并对其进行瞬态动力学分析.在模型中压电结构的热弹性类比方法和界面接触-碰撞算法分别用来模拟换能器激励以及变幅杆与板之间的相互作用.通过分析计算得到板的振动速度的波形和频谱以及接触力的波形和频谱,可知在换能器工作条件下,变... 相似文献
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Finite element modeling of heating phenomena of cracks excited by high-intensity ultrasonic pulses 下载免费PDF全文
A three-dimensional thermo-mechanical coupled finite element model is built up to simulate the phenomena of dynamical contact and frictional heating of crack faces when the plate containing the crack is excited by high-intensity ultrasonic pulses.In the finite element model,the high-power ultrasonic transducer is modeled by using a piezoelectric thermal-analogy method,and the dynamical interaction between both crack faces is modeled using a contact-impact theory.In the simulations,the frictional heating taking place at the crack faces is quantitatively calculated by using finite element thermal-structural coupling analysis,especially,the influences of acoustic chaos to plate vibration and crack heating are calculated and analysed in detail.Meanwhile,the related ultrasonic infrared images are also obtained experimentally,and the theoretical simulation results are in agreement with that of the experiments.The results show that,by using the theoretical method,a good simulation of dynamic interaction and friction heating process of the crack faces under non-chaotic or chaotic sound excitation can be obtained. 相似文献
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