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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2021, Vol. 42 ›› Issue (3): 223855-223855.doi: 10.7527/S1000-6893.2020.23855

• Solid Mechanics and Vehicle Conceptual Design • Previous Articles     Next Articles

Thermodynamics-based damage constitutive model and its application to damage analysis for HTPB/AP composite base bleed grain

WU Zhihui1, NIU Gongjie2, QIAN Jianping1, LIU Rongzhong1   

  1. 1. School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
    2. Institute of Systems Engineering, China Academy of Engineering Physics, Mianyang 621999, China
  • Received:2020-01-29 Revised:2020-03-21 Published:2020-04-25
  • Supported by:
    National Natural Science Foundation of China (11402248)

Abstract: To investigate tensile mechanical properties of HTPB/AP Composite Base Bleed Grain (CBBG), quasi-static (233-301 K, 8.3×10-5-8.3×10-1s-1) and impact (233-323 K, 1 200-8 000 s-1) loading experiments are conducted. Results show that the true stress-true strain curve has an obvious yield point under each experimental condition. The initial modulus, yield stress and the shape of the post-yield region of true stress-true strain curves all present clear dependence on temperature and the strain rate. In the framework of irreversible thermodynamics, the expressions of thermodynamic forces and evolution laws of internal variables are derived. With the additional initial modulus and the yield stress models, a novel viscoelastic-viscoplastic constitutive model considering damage evolution is proposed. Based on experimental data, the one-dimensional version of the constitutive model is used to identify the material parameters. The model validation shows that the proposed model can accurately present the initial viscoelasticity and post-yield behaviors of HTPB/AP CBBG over a wide range of temperature and strain rates. Damage evolution laws indicate that both the impact loading and low temperature boost damage development.

Key words: HTPB/AP composite base bleed grain, thermodynamics, tensile mechanical properties, viscoelasticity, viscoplasticity, damage evolution, constitutive model

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