本文介绍了一种强度型操作自诊断自适应适智能复合材料结构的研究情况。这种智能材料基于电阴应变丝为传感无件，形状记忆合金为动作元件。为使结构具有高的灵敏度及诊断精度，文中研究了传感元件的布置方案，提出了四点布置传感无件的方法。同时采用了形状头记忆合金为动作元件。在自诊断出损伤后，对相应的SMA激励，以减小操作或防止其扩展。

目前，复合材料主要是以蜂窝结构的形式应用于飞机结构中。本文将应力波因子（SWF）技术与智能材料结构技术相结合，对蜂窝夹芯复合材料的损伤实现在线、主动监测。本文提出了先将应力波的时域波形微分后再进行傅立叶变换的方法；验证了应力波在蜂窝夹芯复合材料中传播时，其峰—峰值随距离增大呈指数衰减，并提出一种基于最小二乘法的新型应力波因子技术，可有效的剔除传播距离对信号峰—峰值的影响，提高了损伤判别的可靠性和准确性。

提出并实施了两种改善强度调制型光纤传感器特性的措施：依据其工作原理，改变反向镜面的结构；再采用测量方法，以清除干扰，改善传感器的工作特。这种传感器已应用于实际所研制的光纤位移测量仪及叉光纤维动测量仪光纤振动测量仪。

对于埋入光纤后的3-D编织复合材料结构进行了力学建模，介绍了光纤埋入编织材料结构的编织方法、工艺和走向，构建了含光纤部分编织复合材料结构的内胞模型，分析了光纤与纱线及内胞的相互几何关系，并采用有限多相元法建立含光纤3-D编织复合材料结构的本构关系，理论计算结果与实验结果的相一致验证了光纤编入3-D编织复合材料结构中提高检测结构内部参数方法的可行性。

Simultaneous strain and temperature measurement for advanced 3-D braided composite materials using fibre-optic sensor technology is demonstrated, for the first time. These advanced 3-D braided composites can virtually eliminate the most serious problem of delamination for conventional composites. A tandem in-fibre Bragg-grating (FBG)/extrinsic Fabry-Perot interferometric sensor (EFPI) system with improved accuracy has been used to facilitate simultaneous temperature and strain measurement in this work. The non-symmetric distortion of the optical spectrum of the FBG, due to the combination of the FBG and the EFPI, is observed for the first time. Experimental and theoretical studies indicate that this type of distortion can affect the measurement accuracy seriously and it is mainly caused by the modulation of the periodic output of the EFPI. A simple method has been demonstrated to improve the accuracy for detection of the wavelength-shift of the FBG induced by temperature change. A strain accuracy of ～±20με and a temperature accuracy of B711C have been achieved, which can meet the requirements for practical applications of 3-D braided composites.

An optic-fiber based dynamic pressure sensor is described here to measure weight-in-motion of vehicles. In the research reported herein, a Michelson interferometer with specially designed hardware and software were developed and experimentally subjected to dynamic compressive loads of different magnitudes, and loading rates. Experiments showed that both output fringe number and fringe period could be used to indicate the dynamic load. A calibration technique was put forward to calibrate the sensor. Both the dynamic weight and static weight of the vehicle passed can be obtained. The findings that resulted from these studies developed an understanding for the behavior of interferometer sensor under dynamic compressive states of stress and are fundamental to the application of fiber optic sensors for the monitoring of truck vehicle weights while in motion.

Structure health monitoring based on diagnostic Lamb waves has been found to be one of the most promising techniques recently. This paper has a brief review of the new developments on this method including the basic novel of the method, fundamentals and mathematics of Lamb wave propagation, narrowband and wideband Lamb wave excitation methods, optimization of excitation factors and diagnostic Lamb wave interpretation methods.

Adopting wide-band Lamb wave based active monitoring technology, this study focuses on a neural network method based on a new damage signature for on-line damage detection applied to thin-walled composite structures. Honeycomb sandwich and carbon fiber composite structures are studied. Two kinds of damage are considered: delamination and impact damage. A new damage signature is introduced to determine the presence and extent of damage in composites, while eliminating the influence of different distances between the actuator and sensor. Neural network method is researched to take advantage of this new damage signature combined with several other signatures to decide the damage mode. Kohonen neural network is developed. The proposed method is shown to be effective, reliable, and straightforward for the specimens considered in the present study, which are composed of ifferent materials and suffer various levels of damage.

A reliable understanding of the properties of 3-D braided composites is of primary importance for the successful utilization of these materials. A new method is introduced to study the mechanical performance of braided composite materials using embeddedoptic fiber sensors. Experimental research is performed to devise a method of incorporating the optic fiber into a 3-D braided composite structure. The efficacy of this new testing method is evaluated on two counts. First, the optical performance of the optic fiber is studied before and after incorporation into the 3-D braided composites, as well as after completion of the manufacturing process for the 3-D braided composites, to validate the ability of the optic fiber to survive the manufacturing process. On the other hand, the influence of incorporated optic fiber to the original braided composite is also researched by tension and compression experiments. Second, two kinds ofoptic fiber sensors are co-embedded into 3-D braided composites to evaluate their respective ability to measure internal strain. Experimental results show that multipleoptic fiber sensors can be co-braided into the 3-D braided composites to determine its internal strain which is difficult to be fulfilled by other current existing methods.

Damage characterization takes place by comparing single mode sensor signals collected before and after the damage event. By subtracting the signals of both conditions from each other, a scatter signal is produced which can be used for damage localization. By using Gabor wavelet to analyze single mode Lamb wave recorded before damage and scatter signal, the difference of time-of-flight can be obtained. Combining with the ellipse technique, the localization experiment on fiberglass plate of dimension 100