Design and Fabrication of Integrated Smart Composites

本计画主要研究电流变液在复合材料梁振动抑制上的应用。研究结果分为两类：1.电流变液的驱动性能和2。电流变液和压电陶瓷驱动器混合效应。对一个装有电流变液驱动器的CFRP复合材料梁进行了两种不同频率的电场作用试验。结果表明：（1）矩形波比正弦波更能有效地抑制电流变效应。(2)在频率接近复合材料梁固有频率的电场作用下，观察到复合材料梁的拍频响应.制作了一个粘贴压电陶瓷的电流变液CFRP复合材料梁，并进行了正弦和随机激励实验。采用压电陶瓷作动器的挠度反馈控制（DFC）和速度反馈控制（VFC）两种反馈控制策略来抑制复合梁自由端的挠度。光纤传感器也被用来检测梁的应变响应。结果表明：（1）对于正弦激励，VFC比DFC具有更好的减振效果。(2)考虑到电流变液的抑制效果，必须对压电陶瓷作动器施加输入电压。(3)光纤传感器在电场作用下得到了有效的利用。

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.