基于压电传感器的树脂基复合材料固化过程监测

复合材料固化成型工艺是影响树脂基复合材料结构性能的关键之一，因此需要针对其固化过程进行有效在线监测。本文基于压电传感器提出一种超声导波技术和机电阻抗技术相结合的树脂基复合材料固化过程监测方法，研究了超声导波能量与固化时间的关系及机电阻抗共振峰随固化时间的变化规律。研究表明，固化过程中树脂基复合材料结构的超声导波信号幅值和机电阻抗信号共振峰频率均出现先减小后增大并逐渐平稳的趋势，可以体现树脂基复合材料固化过程中的一系列变化。以监测单向碳纤维(T300)/热固性环氧树脂预浸料固化为例，验证压电传感器对复合材料固化的监测方法。T300/热固性环氧树脂复合材料在真空袋压、固化温度为120℃条件下，20 min为凝胶时间点，65 min为固化完成时间点。本研究基于压电固化过程在线监测方法为树脂基复合材料成型工艺的设计和优化提供了基础数据和技术支撑。 

Piezoelectric transducers based curing monitoring of resin matrix composites

The curing process is one of the key factors for the performance of resin matrix composites, it is necessary to carry out the effective online monitoring for the curing process. In this paper, a method for monitoring the curing process of resin matrix composites was proposed after integrating the two technologies based piezoelectric transducers: The electromechanical impedance technique and the guided wave technique. The interrelation between the curing time and energy of guided wave was analyzed. The variation of signal resonance peaks of electromechanical impedance with the curing time was also discussed. The results show that in resin matrix composites curing, the amplitude of the guided wave signal and the formant frequency of the electromechanical impedance signal both decrease first, then increase and gradually stabilize, which indicates a series of changes in the curing process of resin matrix composites. Taking the case of the curing monitoring of the unidirectional carbon fiber (T300)/thermosetting epoxy prepreg, this monitoring method based on piezoelectric transducers for curing of T300/thermosetting epoxy composite is verified. Under the condition of vacuum bag pressure and curing temperature of 120℃, 20 min is the gel time point and 65 min is the completion time point for T300/thermosetting epoxy composite. The proposed curing monitoring method provides the basic data and technology basis for the design and optimization of the molding process of resin matrix composites.