【摘要】 本文研究了激光连续加热和恒内压作用下柱壳结构的变形规律。以4340钢材料作为研究对象,其本构方程选用热粘塑性本构模型（Johnson-Cook模型）;选取某一应变率为临界值(本文中临界应变率取为1s^-1)。考察了激光功率密度、预载荷大小、激光作用时间等对结构变形规律的影响。主要结论有:结构失稳是导致激光辐照下充内压柱壳破坏的重要原因;激光功率密度和内压越高,结构破坏时间越短;根据辐照时间的长短,预测到了结构急速破坏、延迟破坏和不破坏三种模式。本工作对于深入认识激光作用下预载结构的热-力联合破坏有一定意义。更多还原

【Abstract】 A comprehensive analysis method was developed to study the transient response of a thermal-viscoplastic thin-walled tube under constant pressure and rapid heat input. The deformation and failure mechanism of 4340 steel tube was analytically investigated under various stress level and laser power density. This method can be used to determine parameters related with critical initiation of rupture, such as deposited laser energy, loading, and duration of heating and so on. The threshold time of heating, threshold temperature of material and threshold energy for laser thermal heating coupled with the equivalent stresses causing the structural failure were calculated. The calculated results are consistent with the experiments. The results show that the deformation and failure mode of structure is mainly dependent on the heating duration, and there have three modes: rapid rupture, no rupture and delayed rupture. In general, the higher the loading is, the shorter the rupture time is, and the higher the loading is, the less the temperature of the material. The laser power density has no evident influence for the consumed energy of ruptured material.更多还原