金属射流失稳断裂的理论分析
Instability and breakup of stretching metallic jets
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摘要: 基于Hamilton原理，提出一个包含射流强度、剪切、应变率效应、动力学黏性、表面张力和速度梯度等多因素耦合的金属射流拉伸运动方程，具体分析了各种失稳因素，并由数值解定量给出其影响大小，以及最不稳定波长与初始应变率乘积\lambda_{m}\dot{\varepsilon}_{0} 值的变化范围；给出了射流断裂的时间判据和近似理论公式，计算得到的 t_{b}-\dot{\varepsilon}_{0}曲线与射流实验点、Chou\&Carleone拟合公式三者符合较好.Abstract: Based on the Hamilton principle, a coupled motion equationof stretching metallic shaped-charge jet is presented to study the effectsof yield strength, shear, strain rate, viscosity, surface tension force andvelocity gradient on the jet instability, and the results arequantitatively discussed. The value range ofnon-dimensional \lambda _m \dot {\varepsilon }_0 was obtained toillustrate the product of the wavelength in unstablest solution and initialstrain rate. Furthermore, the criterion and approximate theoretical formulaof jet breakup time are presented. The theoretical results were in fairlygood agreement with the jet experimental data and those from the methoddeveloped by Chou and Carleone.
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Keywords:
- stretching metallic jet /
- motion equation /
- instability factor /
- critical wavelength /
- break-up time
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