共查询到19条相似文献,搜索用时 414 毫秒
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压电材料具有良好的力电耦合性能,被广泛用于诸如传感器,换能器,制动器等的主体材料,可以应用于振动与噪声的控制。基于此,用一片压电材料作为主动吸声系统中的吸声材料,通过等间距布置于压电材料正前方的两个PVDF(Poly Vinylidene Fluoride)传感器检测出平面入射声波声压,利用压电材料的压电性能,在压电材料上加电压,使得反射声波为零,从而达到主动吸声的目的。最后对不同频率入射的平面声波进行了实验,取得了较好的吸声效果。 相似文献
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针对管道低频流噪声难于有效控制的弊端,设计了一种薄膜型声学超材料及其性能测试装置,根据声波传递理论计算了管道内薄膜在声压作用下的振动特性。利用COMSOL软件的声固耦合模块研究了薄膜的消声特性,并进行了对比试验。结果表明:薄膜在低频范围内有较好的消声性能,薄膜的共振频率即为其消声工作频率;薄膜的振幅越大,传递损失值越高,最高达54 dB;薄膜参数的变化对超材料的消声性能有调节作用,通过改变施加在薄膜上的预应力和薄膜厚度,分别实现了传递损失峰值频率偏移120 Hz与110 Hz;通过改变附着质量块大小,实现了100 Hz及以下超低频消声。相关研究为主动声学超材料以及紧凑型管道消声器的设计提供了依据。 相似文献
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白志刚 《中国新技术新产品》2019,(15)
PVDF压电薄膜是一种新型的高分子聚合物型传感器材料,具有高的压电常数,质量轻、柔性好、加工性能好、频率响应宽、对高频激励实用性强等优点,该文利用PVDF薄膜的压电特性设计了一种传感器,通过对传感器测试发现,在测量压力范围内,PVDF压电薄膜传感器具有良好的线性度、较高的灵敏度、较宽的频域响应、较低的迟滞性误差和重复性误差,并且温度对传感器的灵敏度影响较大,实际测试时需考虑温度的影响,激励测试表明PVDF压电薄膜传感器满足测量脉动压力的需求。 相似文献
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提出一种具有可调双消声波峰的压电式消声器,可依据降噪要求来调节电压和穿孔率大小,实现两个低频段的声波吸收可调谐。运用Comsol声固耦合模块计算消声结构参数对频移特性影响的规律:穿孔率减小,双消声峰向低频偏移,第二消声峰的幅值和频率范围明显减小,反共振点位置不变;膜厚增加,第一阶消声峰值基本不变,第二阶消声峰值向低频偏移。分析了不同加载电压下的压电薄膜位移变化情况,搭建实验平台测试不同电压条件下结构的传输特性,基于逆压电效应的压电薄膜可以有效地抑制或增强膜的振动响应,改变反共振点位置,电压由0增加到300 V,第一消声峰值频率向高频偏移85 Hz,第二消声峰向高频域移动了125 Hz。 相似文献
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基于管内平面波分解的热声谐振管声功测量方法 总被引:1,自引:1,他引:0
提出了通过平面声波分解测量热声谐振管中单频压力波声功的方法.在该方法中,只要测量沿程两点的声压,便可将管内平面驻波声场分解为入射波和反射波两种分量.由这种分解可以求出入射波的声功和反射波的声功,二者之和决定了总声功.该方法考虑了粘性耗散和热传导带来的损失,即使在高频、高驻波比情况下也能得到准确的测量结果.由于这种平面波分解的方式可以对整个谐振管内的声场参数进行重构,与以往的双传感器声功测量方法相比,显著优点是不仅能够获得两个压力测点中点的声功,还能得到整个谐振管上沿程各点的声功,这对于分析热声系统各部分的声功耗散是非常有用的,这种方法在原理上也更易于理解. 相似文献
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T.J. Pence H. Tsai 《International Journal of Engineering Science》2002,40(6):647-671
This paper is concerned with the effect of sustained infinitesimal harmonic plane wave excitation of a phase boundary in a non-linearly elastic material that is subject to anti-plane shear deformation. The phase boundary is capable of motion that is here described by a harmonic travelling waveform. The reflected wave is also a harmonic plane wave, however the transmitted wave may be either in the form of a harmonic plane wave or a harmonic surface wave. The phase boundary motion is determined on the basis of a standard kinetic relation that involves a single mobility parameter. This gives phase boundary motion that is synchronized with the incident wave for the case of a transmitted plane wave, but is not synchronized with the incident plane wave for the case of a transmitted surface wave. A certain fraction of the energy provided by the incident wave is dissipated by phase boundary motion in a fashion that can be explicitly quantified. Special incident angles can suppress the reflected wave, suppress the transmitted wave or cause the dissipation to vanish. 相似文献
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This work presents closed-form solutions for free-field motions in a certain type of orthotropic, continuously inhomogeneous half-planes that include both incident and reflected waves from the traction-free horizontal surface. A state of plane strain holds and both pressure and vertically polarized shear waves are considered. The methodology is restricted to media with orthotropic material characteristics that vary quadratically with respect to the depth coordinate. The method of solution is a hybrid approach based on the plane wave decomposition technique, augmented by appropriate functional transformation relations for the displacement vector. The existence of a unique analytical solution as superposition of incident P- or SV-waves and the corresponding reflected P- and SV-waves is proved under certain restrictions on the incident wave direction. Finally, a numerical study reveals the influence of material inhomogeneity and orthotropy on the displacement free-field motion. 相似文献
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采用等效流体模拟吸声材料,建立了外部流场作用下填充吸声材料夹层板结构的声振耦合模型,应用波动分析方法研究结构中声的透射特性,分析了入射声波入射角和方位角、流场流速和流向、夹层结构几何尺寸等参数对填充吸声材料夹层板结构声振耦合特性的影响。仿真计算表明吸声材料提高了双层板结构的隔声性能;隔声性能随着面板厚度和夹层厚度的增加而提高,随着入射角和方位角的增大而减小;在计算频段内(0~5000Hz),逆流入射时传声损失随着马赫数的增大而减小,顺流入射时却随着马赫数的增大而增大。 相似文献
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The linear two-dimensional problem of hydroelastic waves reflected by a vertical wall is analysed. The fluid is of finite depth and is covered by an ice sheet. The fluid is assumed incompressible and inviscid. The ice sheet is assumed thin compared with both the water depth and wavelength of the incident wave. The deflection of the ice sheet is described by linear elastic plate theory, and the fluid flow by using the potential-flow model. The ice sheet extends infinitely and is clamped to the vertical-walled structure. The incident hydroelastic wave is regular. An analytic solution is found by integral-transform methods. The ice deflection, the vertical and horizontal forces acting on the wall and the bending stresses in the ice caused by the incident wave are determined. The forces on the wall are analysed in detail, and relevant physical parameters are varied for comparison. The phase shift between the incident and reflected wave amplitudes is found as part of the complete solution. It is shown that the ice clamping condition leads to a specific effect on the ice deflection. 相似文献
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为了吸收低频入射声 ,作者提出了一种有源吸声结构 ,本文从理论上研究了该结构的吸声性能。文章首先建立理论模型 ,然后通过近场方法和求解弹性板 -声腔耦合系统结构响应推导了有源控制前后反射声功率的计算公式 ,然后按声反射功率最小化准则求得最佳有源吸声效果。最后通过一系列算例证明了该吸声结构吸收低频声波的有效性 ,并研究了吸声效果与次级力源位置的关系 相似文献
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W. Hussain 《Acta Mechanica》2009,203(1-2):63-75
This paper is concerned with the effect of finite pure homogeneous biaxial stretch together with simple shear deformation on the reflection from a plane boundary of elastic waves propagating in a half-space of incompressible isotropic elastic material. This generalizes the previous work in which, separately, pure homogeneous strain and simple shear were considered. For a special class of constitutive law, it is shown that an incident plane harmonic wave propagating in the considered plane gives rise to a surface wave in addition to a reflected wave for every angle of incidence. The amplitude of the surface wave may vanish at certain discrete angles depending on the state of stress, biaxial stretch and simple shear deformation and then specialized to recover results obtained previously. The amplitude of the reflected wave is independent of the pre-stress but does depend upon the magnitude of deformation under consideration. The dependence of the reflected and surface wave behavior on the angle of incidence, amount of shear strain, biaxial stretch and the state of stress is illustrated graphically. 相似文献