宽温域宽应变率下丁羟四组元 HTPB 推进剂单轴压缩力学行为

In order to investigate the uniaxial compression mechanical behavior of four‐component HTPB propellant under wide temperature and wide strain rate ranges，uniaxial compressive mechanical performance tests of propellant were conducted under wide temperature and strain rate ranges based on universal material testing machine，high‐speed hydraulic servo testing machine，split Hopkinson pressure bar，and programmatic constant temperature and humidity testing machine. Stress‐strain curves of HTPB propellant under 10^-4-10³ s^-1 at -40，-25，-10，20 ℃ and 50 ℃ were obtained，and the segmented uniaxial compression rate‐temperature constitutive relationship of HTPB propellant was established. The results indicate that the mechanical response of HTPB propellant exhibits a significant rate‐temperature correlation. At any strain rate，its mechanical response undergoes staged changes，i.e.，linear elastic stage‐nonlinear yield stage‐strain softening or strain hardening stage. Moreover，at high strain rates，the strain softening phenomenon after the nonlinear yield behavior is significantly weaker than that at low and medium strain rates. In addition，at high strain rates，as the temperature decreases，the changing rate of the stress‐strain curve gradually slows down；while at low and medium strain rates，the changing rate of the stress‐strain curve gradually increases as the temperature decreases. The mechanical strength of HTPB propellant increases significantly with decreasing temperature. When the temperature drops from 50 ℃ to -40 ℃ ，the maximum stress under wide strain rate increases from about 2.2-8.8 MPa to 11-22 MPa. The segmented rate‐temperature constitutive relationship constructed based on the experimental data has a better fitting effect at higher temperatures，which can better predict the mechanical behavior of HTPB propellant.