粒状发射药巴西试验的力学分析

Mechanical Analysis of Granular Propellant by Brazilian Test

针对发射药的受力特点,采用巴西试验对发射药的力学性能进行了试验研究,应用弹性接触理论和弹性力学平面问题的相关理论分析了其应力分布规律,结合Griffith强度准则得到了发射药抗拉强度的计算公式。结果表明,初始裂纹发生在发射药的中心部位,并发生对径劈裂,表明巴西试验适用于测量发射药的抗拉强度;发射药抗拉强度是由发射药破碎时的载荷和发射药和压头的接触面宽度决定;当储存时间由39 a延长到47 a时,发射药的抗拉强度由13.11 MPa变为12.58 MPa,减小4%。

For the loading features of propellant,the mechanical properties were studied by brazilian test. Theories of Hertz elastic contact and elastic mechanics plane stress were applied to analyze the stress distribution law,and the formula was obtained to cal-culate tensile strength for propellant from Griffith strength criteria. Results show that the initial crack forms at the center region of propellant and propagates along the loading direction,which proves that the Brazilian test is suitable for measuring tensile strength of propellant. The tensile strength of propellant is determined by the load when the splitting happens and the contact width be-tween propellant and indenter. When the storage time extends from 39 years to 47 years,the tensile strength of propellant changes from 13. 11 MPa to 12. 58 MPa,decreasing by 4%.