新型 GAP / RDX / TEGDN 推进剂宽应变率下的力学性能及模型参数标定

The accuracy of mechanical model parameters of high-energy and low-vulnerability solid propellant is of great significance to the prediction of its macroscopic mechanical response. In order to decouple the parameters of the viscoelastoplastic damage model of solid propellant, a model parameter calibration method based on experiment is proposed. The viscoelastoplastic damage parameters of GAP / RDX / TEGDN (GRT) solid propellant are calibrated by the quasi-static and dynamic tests using a universal testing machine and a split Hopkinson pressure bar device. The mechanical properties and damage mechanism of GRT at a wide range of strain rate are analyzed. The experimental results show that the mechanical behavior of GRT propellants is obviously strain rate-dependent, and the tensile strength and elongation are increased by 75% and 43. 33%, respectively, with the increase in the tensile rate (1 - 1 000 mm / min). With the increase in quasi-static compressive strain rate (0. 001 - 1 s^{- 1} ), the yield strength is increased by 16. 67% . With the increase in dynamic compressive strain rate (2 100 - 4 100 s^{- 1}), the yield strength is increased by 72. 98% . The fracture strain of the material is related to the stress state. The fracture strain is decreased by 36. 36% with the increase in stress triaxial degree (η = 0. 33 to η = 0. 74). In addition, according to the microscopic characterization of GRT propellants, the main failure mechanism is interface debonding under quasi-static stretching, and the main failure mechanism is particle breakage under quasi-static and dynamic compressions. On this basis, the parameters of Plastic-Kinematic constitutive model are calibrated by quasi-static and dynamic compression tests, the parameters of Prony series are calibrated by stress relaxation test, and the parameters of fracture damage model are calibrated by notch test and quasi-static tensile test. Therefore, the model parameters could be calibrated more accurately by the proposed method. It provides support for the prediction and analysis of macroscopic mechanical properties of propellants.