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压电梁振动的多输入多输出主动控制 总被引:2,自引:1,他引:1
对表面上贴有多个用作驱动器和传感器的压电陶瓷片的“压电梁”结构,导出了从驱动器到传感器的频响函数公式,作为压电结构设计和振动控制的数学模型。提出了压电梁对缓变周期扰动振动环境的多输入多输出振动抑制方法。 相似文献
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为了解基于压电阻抗方法识别管道裂纹损伤程度的可行性,通过人工切割方法模拟管道裂纹损伤,采用压电阻抗方法对管道裂纹损伤进行监测试验。实测各种损伤工况下压电片的阻抗信号,分析试验数据,提取均方根差(RMSD)作为损伤指标。基于RMSD 损伤指标与损伤面积的变化规律,建立了管道损伤程度量化表征的数学模型。试验结果表明:当管道出现裂纹损伤后,PZT 阻抗频谱曲线明显向左偏移,峰值对应频率下降;随着管道裂纹损伤程度不断加大,RMSD 值逐渐增长,RMSD 损伤指标能定性地判断管道损伤状况。所建立的数学模型在一定程度上实现了管道裂纹损伤的定量分析。 相似文献
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本文设计了一种压电陶瓷复合材料参数自动测量系统,通过测量压电陶瓷的四种标准型振子谐振峰附近的阻抗(或导纳),即可由本文设计的自动迭代算法自动求出压电陶瓷的全部复材料系数。实验证明:与常用手Smits迭代法相比,本文自动迭代法巧妙的初值选取方法及迭代频率点的选择,使得算法精度高,迭代次数少。 相似文献
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介绍了基于压电导纳的结构健康监测技术基本原理;利用该技术对钢框架结构进行了螺栓松动检测试验研究。即将三个压电陶瓷片粘贴在钢框架节点处的不同构件表面,通过测量框架节点处各压电陶瓷片在螺栓松动前后电导纳的变化来识别损伤.试验结果发现,位于连接板处的压电陶瓷片对该节点处的螺栓松动最敏感,而与螺栓不直接相连的上斜撑上的压电陶瓷电导纳则几乎不受连接板螺栓松动的影响。分别定义了基于电导纳实部和虚部改变的均方根(RMSDR和RMSDI)作为损伤程度识别指标,对框架节点的螺栓松动损伤程度进行了定性识别研究。通过对得到的RMSDR和RMSDI两种损伤指标值对比发现,基于压电导纳实部信息定义的损伤程度识别指标RMSDR能较好地识别框架节点螺栓松动损伤程度,而基于电导纳虚部定义的识别指标RMSDI则不能正确识别。 相似文献
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结构振动主动控制可以采用压电自感知执行器。空分复用解耦方法是实现压电自感知执行器的一种新方法,实质是采用几何方法解耦,即将压电片的一个完整电极分割为执行区和传感区以实现自感知。本文以悬臂梁为对象,以涡流位移计作为标准传感器,对两种电极分割方式的压电片的传感和执行效果进行了实验研究。通过测量压电梁的频率特性,证明了空分复用的压电陶瓷片同时兼有传感和执行两种功能。实验结果也表明传感区的敏感输出受到执行区激励电压的静电耦合的影响,利用悬臂梁存在反谐振点的特性,提出了一种定量测量静电耦合的方法,并测定了不同电极宽度、不同极间隙下的静电耦合系数。本文的工作为采用空分复用的压电自感知执行器进行振动主动控制奠定了基础。 相似文献
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大位移压电陶瓷驱动器的设计与试验 总被引:2,自引:0,他引:2
针对大位移压电陶瓷驱动器,研究了压电陶瓷双晶片的驱动效能。基于压电陶瓷材料的逆压电效应,应用压电陶瓷双晶片在机械自由、电学短路状态下,一片加正向电压缩短另一片加反向电压伸长共同作用产生弯曲变形,通过组合设计将压电陶瓷双晶片的弯曲变形位移叠加起来,实现了压电陶瓷驱动器的大位移输出。在相同电压的条件下,此压电陶瓷驱动器的输出位移量比叠层驱动器有较大的增加,达200μm,结构尺寸也大大减小。该驱动器不需要位移放大机构,可直接应用于有大位移要求的机构驱动。 相似文献
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研究了PZT系梯度功能压电驱动器谐振状态的机电响应特性,通过改变驱动电场和频率,研究其谐振频率和顶端位移的变化特性。结果表明:增加电场,谐振频率减小,谐振点位移增大,并逐渐趋向饱和。在谐振点附近,悬臂梁弯曲位移达到最大值。 相似文献
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The electro-mechanical impedance (EMI) technique using piezoelectric lead zirconate titanate (PZT) transducers has been shown promising for health monitoring of steel structures. For damage assessment, statistical techniques such as root mean square deviation (RMSD) have been employed to compare the electro-mechanical (EM) admittance signatures acquired before and after damage. However, using the conventional RMSD approach, it is difficult to specify the damage severity and location. To overcome this limitation, a sub-frequency interval approach has been proposed by the authors for the concrete structures. In the present study, this approach is extended and applied to the steel structures. Considering low attenuation of wave and large sensing region of PZTs in steel structures, multiple PZTs are utilized to acquire the EMI signatures of an I-section steel beam. Artificial damage points are induced in the steel beam and the corresponding RMSD values for sub-frequency ranges (RMSD-S) are calculated. To qualitatively study the damage severity and location, a method combining the RMSD-S of multiple PZTs and the logarithmic attenuation of ultrasonic waves is proposed. The results demonstrate that the proposed method is robust and sensitive for damage assessment of steel structures. 相似文献
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Delamination is one of the most prevalent failure mechanisms for laminated composites. To secure the safety of composite structures, it is required and necessary to develop cost-effective and efficient delamination detection techniques and methods. In this paper, a dynamic analytical model, namely sensor charge output deviation method is proposed to identify a delamination embedded in a cantilever laminated composite beam bonded with isolated piezoelectric actuator and sensor patches. Two pairs of collocated piezoelectric patches are bonded on top and bottom surfaces of the beam and used as actuators for exciting the composite beam. Another piezoelectric patch with gridding electrode pattern on its top surface is bonded on the top surface of the host beam and is employed as a sensor to record the required voltage and thus the sensor charge output along the beam. The effects of some major geometric parameters and the type of applied electric voltage on the sensor charge output distribution and delamination detection sensitivity are discussed in this paper. A comparison between the analytical models using isolated piezoelectric actuator and sensor patches and that using integrated piezoelectric sensor/actuator layer, which was developed previously, is conducted. For the baseline case considered here, there is an excellent agreement of the first three order frequencies between the present finite element analysis and analytical models. 相似文献
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This paper presents a structural health monitoring technique based on analysis of the dynamic signature of the structure, which changes as damage occurs, due to alterations in structural properties such as stiffness and damping. Experiments performed on plate specimens and T-joint specimens which had various degrees of damage in the form of delaminations showed that it is possible to quantify the effect of damage on the acoustic response resulting from a tap in thick GFRP laminates. Subsequent experiments were conducted on adhesively bonded GFRP composite beam specimens with artificial delaminations of various sizes and locations embedded in the bondline. The specimens were excited using piezoelectric actuators bonded to the surface at various locations and the structural and acoustic responses were analysed. The results of these tests and analyses are presented and it is concluded that the structural and acoustic responses of such specimens to a piezoelectric actuator can be used to identify the presence of a delamination and may potentially be used to determine its size and location. 相似文献
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S. Raja K. Venkata Rao T. Munikenche Gowda 《International Journal of Mechanics and Materials in Design》2017,13(1):25-41
The main emphasis of the present work is to model a piezoelectric beam with edge debonded actuator by employing finite element method based layerwise shear deformation theory, to improve the accuracy with which the actuation authority and natural frequencies are computed. The surface-bonded piezoelectric actuators and the host beam are considered to rotate individually due to shear deformation, while they are assumed to undergo the same flexural deflection and slope. These modeling aspects have improved the accuracy of the computed results. Edge debonding of actuator is accounted in the model by modeling healthy and debonded regions of the beam individually and subsequently applying the displacement continuity conditions at the interfaces of different regions. The investigations are carried out to find the effect of different extents of edge debonding on the actuation authority and natural frequencies of the debonded piezoelectric beam. It is found from the numerical results that the behaviour of the beam with edge debonded actuator is affected considerably as regards to the actuation authority and marginally with respect to natural frequencies. Further it has been shown that, when an actuator is edge debonded it introduces the local modes besides displaying significant reduction in its actuation authority. 相似文献
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This paper describes the use of an integrated piezoelectric sensor/actuator (IPSA) layer to detect a delamination in a laminated composite beam by monitoring the sensor charge output (SCO) distributions along the beam of the first three order frequencies. For the sake of predicting the first three order frequencies and SCO distributions using the IPSA layer, a model-based delamination detection approach is presented. The corresponding dynamic analytical model that includes parameters characterizing delamination is developed using the classical beam theory and the assumption of constant peel and shear strains through the bond line thickness in bonded joint. Using the present analytical model, the effects of delamination length ld, delamination gap tg, actuator segment length la, actuator segment location Xa and electric field E on the SCO values are discussed. Finally, a comparison of the first three order frequencies between the present analytical and finite element analysis (FEA) models reveals that there is good agreement between these two models. 相似文献
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This paper presents a laminated element for piezoelectric (PZT) smart beams in taking into account peel stresses. In the finite element analysis (FEA) formulation, a coupled electrical and mechanical beam element is used to model PZT patches, and a conventional structural element is used to model a host beam. A continuous adhesive element with shear and peel stiffness is derived to form a PZT laminated element. For a smart beam with a partially bonded PZT patch or distributed PZTs, the laminated element is applied to an area of the host beam with PZTs and the conventional element is used in the host beam where no PZT is bonded. A novel PZT laminated element is firstly derived based on the Timoshenko beam theory, in which the FEA formulation based on the Euler-Bernoulli beam theory can be considered as its special case. FEA numerical results of static and dynamic analyses based on the Euler-Bernoulli beam theory are compared with the exact static and dynamic solutions to validate the present FEA formulation. The present FEA framework based on the Timoshenko beam theory is then used to investigate the effects of PZT debondings on static behaviors and dynamic responses, and an original and effective procedure for detecting debondings in PZT actuators or sensors is proposed.The authors are grateful to the support of the Australian Research Council through a Large Grant Scheme (Grant No. A10009074). 相似文献