Non-contact full-field dynamic strain reconstruction of rotating blades under multi-mode vibration

•The full-field dynamic strain of rotating blades under multi-mode vibration is reconstructed by BTT and displacement-to-strain transmissibility matrix.•A least-square decoupling model is established to identify multi-mode vibration parameters of rotor blades.•An analytical relationship between the blade-tip displacement and the full-field strain is derived.•The blade strain/stress distribution is visualized via the finite element model.