[目的]针对船用核动力高能管道断裂防甩设计问题,[方法]采用LS-DYNA软件对典型的主蒸汽管道U形防甩装置的甩击动态过程进行非线性有限元分析,以计算得到应力—应变分布及U形防甩装置(U形箍)甩击力时历曲线随管箍初始间隙、管箍轴向位置的变化规律.[结果]结果表明:在管道断裂甩动过程中,U形防甩件在初始碰撞时甩击力峰值最大,在多次碰撞后甩击力接近静态支反力;在管箍初始间隙40~120 mm范围内,最大甩击力随装置初始间隙的增加而增大,增幅逐渐减小,动态放大系数达到1.74;在管箍轴向位置1.5D~2.5D范围内,最大甩击力随管箍轴向位置的增加略有降低,降幅仅2.5%;方截面U形板防甩装置相比传统多根U形箍防甩件,不仅截面积减少了16.3%,而且最大甩击力也降低了5.5%.[结论]分析结果说明,U形防甩装置最大甩击力与管箍初始间隙正相关,但动态放大系数存在限值,方截面U形板防甩装置承载能力更强.%[Objectives]To address the high-energy pipe whip design problem faced by the nuclear power plants of ships,[Methods]LS-DYNA software is used to establish a nonlinear finite element model of the main steam pipe and U-shaped whip restraint device(i.e U-bolt)so as to simulate the dynamic whipping process.[Results]It is found that the whip restraint rejection force reaches its maximum peak at the primary collision and reduces towards the static support reaction after several collisions. Within a range of 40-120 mm,the maximum rejection force increases as the initial clearance between the pipe and U-bolt whip restraint device is increased,while the increasing slope gradually reduces and the dynamic magnification factor comes to a limit of 1.74.Within the range of 1.5D- 2.5D,the maximum rejection force decreases slightly by 2.5% as the relative axial location between the pipe and U-bolt whip restraint device is increased. Compared with the U-bolt whip restraint,the U-shaped plate can not only reduce the cross-sectional area by 16.3% but also lessen the maximum rejection force by 5.5%.[Conclusions]The analysis results show that the maximum rejection force of the U-shaped plate whip restraint device has a positive correlation with the initial clearance of the restraint,but there is a limit to the dynamic magnification factor,the square section U-shaped plate whip restraint device has greater bearing capacity.
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