3D thermal deformation measurement of superalloy honeycomb panels in time-varying thermal radiation environment

Superalloy honeycomb panels with the advantages of light weight, high strength and excellent heat-shielding properties have been widely used in the field of aeronautics and astronautics. Deformation measurement of superalloy honeycomb panels due to transient thermal loading is essential for the design of heat-shielding structures. Firstly, a self-developed infrared radiation transient aerodynamic heating simulation system was used to simulate conditions similar to transient aerodynamics service conditions and a novel active imaging three-dimensional digital image correlation (3D-DIC) method was used to measure 3D thermal deformation of a superalloy honeycomb panel sample with a size of 210 mm×210 mm at different times in time-varying thermal radiation environment. Secondly, to ensure the reliability of measurement by using 3D-DIC, a new technique for making large-area high-temperature speckle pattern on a test sample was proposed. The high-temperature speckle pattern stayed stable throughout the experiment and could be used as an effective carrier of thermal deformation. Finally, the largest warping displacement was also calculated by Hoff's equivalent stiffness theory. Study results indicate that in-plane thermal expansion is homogeneous when the panel is heated one-side by radiation heating, while the out-plane displacements show evident axisymmetric warp deformation with the largest warping displacement of approximate 1.6 mm at a temperature of 900℃. The experimental results agree well with theoretical predictions made by Hoff's equivalent stiffness theory.