光纤布拉格光栅监测CF3052/5224复合材料成型过程研究

温度与应变是监测复合材料热压罐固化成型工艺两个最重要的表征参数,利用光纤布拉格光栅传感原理,采用毛细钢管封装的方法,制备了完全屏蔽应变信号的温度传感器,将温度传感器和应变传感器同时埋植在复合材料内部,实现了对热压罐成型全过程的实时监测,获得了复合材料成型过程中的内部温度和应变信息.对复合材料平板件和T型加筋板三角填充区域进行的温度监测结果表明,复合材料内部温度变化较罐内温度有一定滞后,传统成型工艺控制给出的加压点偏早,可能引起复合材料贫胶等缺陷.应变监测结果表明,平板件内部的应变变化主要反应树脂固化过程中的物理化学变化,在T型加筋板三角填充区域,应变监测在自然冷却阶段出现了不同于平板件的应变"回弹"现象,一定程度上反映出该区域在成型过程中容易出现缺陷的原因.

Study of monitoring CF3052/5224 composites molding process by optical fiber Bragg grating

Temperature and strain are two of the most important parameters for monitoring the autoclave curing process of composites. The temperature sensor was encapsulated by a steel capillary pipe to shield strain signals. A temperature sensor and a strain sensor were implanted inside the composite simultaneously to monitor the autoclave process in real time so as to obtain internal temperature and strain information. A plate laminate and the triangular region of a T?stiffened panel were monitored. The monitoring results show that the temperature increaseinside the composite was delayed due to the heat transfer. Thus, the pressure applying moment normally determined by the autoclave′s temperature may be improper. This phenomenon may cause the defects such as resin starvation. Strain monitoring results show that the strain changes inside the plate laminate can reflect the physical and chemical varieties of the resin during the curing process. In the triangular region of the T?stiffened panel, there is a "strain rebound" phenomenon during the natural cooling stage, which indicates that the process?induced defects are prone to occur in the triangular region of a T?stiffened panel.