نتایج جستجو برای: piezoelectric layer free vibration
تعداد نتایج: 836736 فیلتر نتایج به سال:
Abstract: Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration abso...
Free bending vibration analysis of the functionally graded viscoelastic circular sandwich plates is accomplished in the present paper, for the first time. Furthermore, local shear corrections factors are presented that may consider simultaneous effects of the gradual variations of the material properties and the viscoelastic behaviors of the materials, for the first time. Moreover, in contrast ...
در این تحقیق یک روش ساده ریاضی برای تحلیل تقریبی ارتعاش آزاد سیستم ترکیبی قاب محیطی تودرتو همراه با مهار بازویی و کمربند خرپایی در سازه های بلند به منظور تعیین فرکانس های طبیعی و اشکال مودی معرفی گردیده است. اثر مهار بازویی و کمربند خرپایی بر قاب محیطی به صورت فنر خمشی در محل قرارگیری مهار بازویی و کمربند خرپایی مدل شده است. فنر خمشی در خلاف جهت دوران ناشی از بارهای وارد عمل می کند و باعث کاهش ...
Active vibration control is an important problem in structures. One of the ways to tackle this problem is to make the structure smart, adaptive and self-controlling. The objective of active vibration control is to reduce the vibration of a system by automatic modification of the system's structural response. This work features the modeling and design of a Periodic Output Feedback (POF) control ...
In this study, A finite element model based on the third order theory is presented for the active vibration control of composite beams with distributed piezoelectric sensors and actuators. For calculating the total charge on the sensor, the direct piezoelectric equation is used and the actuators provide a damping effect on the composite beam by coupling a negative velocity feedback control algo...
We report on a novel microfabrication method to fabricate aluminum nitride (AlN) piezoelectric microstructures down to 2 microns size by a surface micromachining process. Highly c-axis oriented AlN thin films are deposited between thin Cr electrodes on polysilicon structural layers by rf reactive sputtering. The top Cr layer is used both as a mask to etch the AlN thin films and as an electrode ...
− A piezoelectric accelerometer output voltage with zero shift was induced by the low-frequency response of the charge amplifier. So we designed a virtual amplifier with same input-output characteristic as the charge amplifier, and shock sensitivities of a piezoelectric accelerometer were evaluated by applying the input acceleration to the virtual amplifier. The shock sensitivities were compara...
In order to meet the requirements of cable fault detection, a new structure of piezoelectric accelerometer was designed and analyzed in detail. The structure was composed of a seismic mass, two sensitive beams, and two added beams. Then, simulations including the maximum stress, natural frequency, and output voltage were carried out. Moreover, comparisons with traditional structures of piezoele...
A novel piezoelectric energy harvester equipped with two piezoelectric beams and two cylinders was proposed in this work. The energy harvester can convert the kinetic energy of water into electrical energy by means of vortex-induced vibration (VIV) and wake-induced vibration (WIV). The effects of load resistance, water velocity and cylinder diameter on the performance of the harvester were inve...
This paper presents a self-powered piezoelectric energy harvesting circuit using frequency conversion. A vibration energy harvesting principle is introduced. Due to a capacitive characteristic of the piezoelectric vibration transducer, an energy harvesting circuit is proposed for matching the capacitive impedance. The energy harvesting circuit consists of a matching circuit with up-conversion, ...
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