Design and Fabrication of Integrated Smart Composites

本课题主要研究电流变液在组合梁振动抑制中的应用。研究结果分为两类：1.电流变驱动性能；2.电流变与压电陶瓷的混合效应。对带有ERF作动器的碳纤维复合材料梁在两种不同频率的电场作用下进行了试验。这些结果总结如下：(1)矩形波比正弦波更能有效地控制电流变效应。(2)在频率接近于复合梁固有频率的电场作用下，观察到了复合梁的拍频现象。制备了含电流变纤维和粘结压电陶瓷的碳纤维复合梁，并在正弦和随机输入下对其进行了激励。针对复合材料梁自由端的挠度，采用了两种反馈控制策略：挠度反馈控制(DFC)和速度反馈控制(VFC)。还使用了光纤传感器来检测梁的应变响应。得到以下结论：(1)对于正弦激励，VFC比DFC具有更好的减振效果。(2)考虑到电流变流体的抑制作用，必须对压电陶瓷驱动器施加输入电压。(3)在电场作用下，光纤传感器得到了有效的利用。

In the present project, the application of electro-rheological fluids (ERF) to vibration suppression of a composite beam was mainly examined. The results are divided into two categories : 1. ERF actuation performances and 2. hybrid effect of ERF and piezoceramics actuators.1. A CFRP composite beam with an ERF actuator was tested subjected to electric fields of two types of waveforms with various frequencies. These results are summarized as follows ;(1) The rectangular waveform is more effective for control of ER effects than the sinusoidal wave.(2) The beat phenomena is response of the composite beam have been observed subjected to the electric fields with frequency close to the natural frequency of the composite beam.2. A CFRP composite beam containing ERF with bonded piezoceramics was prepared and excited by sinusoidal and random inputs. Two kinds of feedback control strategies, deflection feedback control (DFC) and velocity feedback control (VFC) for the piezoceramic actuator were adopted to suppress the deflection at the free end of the composite beam. An optical fiber sensor was also used for detecting the strain responses of the beam. The following results were obtained ;(1) For sinusoidal excitations, VFC was more effective than DFC in suppressing vibration.(2) Input voltage to the piezeceramic actuator must be applied considering the suppression effect of ERF.(3) The optical fiber sensor was effectively utilized under the electric field.