基于光感密度光纤位移传感器的复合材料热膨胀系数高精度测量方法

High Precision Measurement Method for Composite Material Thermal Expansion Coefficient Based on Optical Density Fiber Displacement Sensor

由于具有比强度和比模量高等优点,复合材料结构件在航空航天领域应用日益广泛。在高温、高寒等恶劣的环境下,飞机结构会由于温度变化产生变形和应力,从而导致结构的破坏,因此需要在仿真阶段输入复合材料的热膨胀系数,以预测其可能出现的问题。文中提出了一种基于光感密度光纤位移传感器的复合材料热膨胀系数测量方法,首先介绍了其硬件组成及数据采集的软件系统,可以保证试件变形量和温度变化量的高精度同步采集;然后根据该系统数据采集的特点,对热膨胀系数及其不确定度计算进行了分析,并建立了对应的计算模型。最终以某新型碳环氧复合材料试件-100^+100℃温度区间内的热胀系数为例,验证了软硬件平台及计算模型的有效性和可用性。

Composite material component has been increasingly widely used in aerospace industry due to its advantages such as high specific strength and specific modulus.When used in mal-conditions,structural failure caused by temperature variation is likely to happen,hence,the simulation analysis of structure is needed before its final application.Therefore,thermal expansion coefficient should be accurately measured because it will considerably affect the accuracy of simulation computation.In this paper,an accuracy improving measurement method for composite material thermal expansion coefficient based on optical density fiber displacement sensor was presented.First,hardware and software system was introduced,they can make sure the synchronism and precision of the data collection including temperature and displacement.Then,mathematical model of thermal expansion coefficient and its measurement uncertainty was established according to the characteristics of this system.An example of thermal expansion coefficient of composite material during-100 ℃ to 100 ℃ was used to verify the practicability and effectiveness of this system.