空间环境铝合金板结构热属性光纤监测技术研究

Monitoring Technology of Thermal Properties of Aluminum Alloy Plate Structure under Space Environment Based on Fiber Optic

针对空间结构受热循环载荷作用而影响航天器功能与安全的情况,采用温度补偿方法,对基于分布式光纤传感器的板结构热应变和热变形测量技术进行研究,提出了一种基于光纤应变转换矩阵的铝合金板热膨胀系数计算方法,考虑了材料横向应变对结构热膨胀系数测量精度的影响,可为各向异性复合材料构件多方向热膨胀系数测量提供理论支持。研究表明:温度-70~100℃范围内,铝合金板所受热应变引起光纤光栅中心波长偏移量约462.4pm,中心波长偏移量与温度的相关系数约0.999;在温度100℃热载荷作用下,铝合金板在横、纵向变形量均约0.75mm;铝合金板热膨胀系数随温度变化呈现非线性,低温下不能将铝合金材料热膨胀系数近似为常数。研究为后续航天器空间服役状态在轨监测提供参考。

Aiming at the situation that thermal cycle load effect acts on space structure and affects the function and safety of spacecraft,with temperature compensation method,measuring technology of the plate structure thermal strain and deformation based on distributed fiber optical sensors was carried out.Additionally,an aluminum alloy plate thermal expansion coefficient calculating method based fiber optical strain transfer matrix was proposed,which not only helped eliminating the influence of material transverse strain on measuring precision of structure thermal expansion coefficient,but also provided theory support for multidirectional thermal expansion coefficient measurement of anisotropic composite.This result shows when temperature ranges from-70 to 100℃,the center wavelength shift caused by thermal strain acting on aluminum alloy plate is 462.4pm,and the correlation coefficient between center wavelength shift and temperature is about 0.999;aluminum alloy plate thermal deformations on transverse and longitudinal direction are both about 0.75 mm under thermal load of 100 ℃.Aluminum alloy plate thermal expansion coefficient takes on nonlinearity with temperature change,especially in low temperature,which is not approximate to constant.Research results may be benefit for in-orbit monitoring of spacecraft serve status in future.