关键词: 热变形, 数字图像相关方法, 单相机3D-DIC, 主动成像, 紫外相机

Abstract: Accurately characterizing the mechanical performance of the thermal protection materials and structures of hypersonic flight vehicle in extreme high-temperature environments has always been a challenging issue in ground assessment tests which confuses the related engineering technicians. This paper establishes a single-camera 3D-DIC measuring system based on a single normal camera/UV camera and a four-mirror adapter. To overcome the intensified heat radiation problem during high temperature measurement, active optical imaging device including high-brightness monochrome illumination light (blue/ultraviolet light) and band-pass filtering imaging is integrated with the system. First, the in-plane and out-of-plane translation experiments verify the measurement accuracy of the active-imaging single-camera 3D-DIC system. Subsequently, the thermal deformation on the in-directly heating surface (back surface) of the stainless steel and alumina ceramic specimens was measured by the established blue-light single-camera 3D-DIC system, and the determined coefficients of thermal expansion are close to the reference values in aeronautical material handbook. Finally, the thermal deformation on the directly heating surface (front surface) of the stainless steel specimen was measured using the established UV-light single-camera 3D-DIC system, and the measured coefficient of coefficients was also close to the reference value.

Key words: thermal deformation method, digital image correlation, single-camera 3D-DIC, active imaging, UV camera