【作者】 宋军；

【导师】 徐秉业；

【作者基本信息】 清华大学 ， 固体力学， 1990， 博士

【摘要】 本文提出了粘塑性本构关系式中过应力函数的反函数表达式。在常温和高温条件下,对炮钢进行了材料屈服极限的塑性冲击实验。在此基础上,对受冲击载荷作用的筒结构进行了比较全面的弹粘塑性动态分析和准静态分析,导出了筒的弹性区与弹粘塑性区的分界半径随时间变化的规律。同时还分析了惯性效应和弹性变形对粘塑性计算结果的影响。在环境温度中,导出了筒的热粘塑性应力和变形结果。这些分析和实验结果为火炮的动态设计等工程问题提供了理论依据。 本文还对软钢材料在不同速率条件下的循环加载进行了实验研究和理论分析。提出了考虑应变率影响的线性强化正向和反向加载屈服准则,对筒的弹塑性加载、卸载和反向加载过程进行了解析分析。在此基础上,对不同加载速率条件下筒的自紧工艺过程进行了计算和比较,得到了有价值的结论。更多还原

【Abstract】 In the present thesis a new version of over-stress function of viscoplastic constutitive equation is proposed. The impact experiment of the certain steel is examined by means of SHPB method under the room temperature and the elevated temperature situations.The quasi-static and dynamic elasto-viscoplastic solutions of the thick-walled cylindrical shell are analyzed in detail. The radius of the interface of elastio and viscoplastic regions with respeot to time is derived.The effects of the inertia and the elastic deformation on viscoplastic solutions are discussed respectively. The thermo-viscoplastic solutions are presented in the stable temperature field.Another experiment considering the influence of strain-rate on mechanical parameters of low-carbon steel is made in INSTRON test machine under loading , unloading and cyclic loading conditions. The stress yield criterion including strain-rate variable is proposed. Analytical solutions of a tube subjected to the internal pressure are derived by using the proposed criterion during the loading , unloading and reversed loading process.The effect of strain-rate on the mechanioal autofrettage tube is discussed.更多还原