事故型撞击荷载作用下大型LNG储罐穹顶局部破坏形态分析

Analysis of local damage pattern of large LNG storage tank dome under accident-type impact load

为了确定事故型撞击荷载作用下大型LNG储罐穹顶的局部破坏形态,以ф101.6 mm NPS法兰冲击能量为参照,选取穹顶局部壳体为靶体,利用等效飞射物弹体自由落体撞击靶体进行了15个工况冲击试验。通过对试验结果分析研究,标定了冲击成坑、冲击震裂、冲击剥落屈曲、冲击侵彻屈曲、冲击贯穿屈曲5种破坏形态,并给出了特征形态图。通过引入薄钢板弹道极限速度对侵彻贯穿屈曲破坏形态的侵彻深度进行修正,给出了以侵彻深度与穹顶厚度比值。这一无量纲参数为基准的破坏形态判断标准。最后,提出了事故型撞击荷载作用下LNG储罐穹顶的破坏等级划分标准,验证了Petry公式和BRL公式用于侵彻深度估算的有效性。

In order to determine the local damage pattern of large LNG storage tank dome under accidental impact load ,the impact energy of Ф101.6 mm NPS flange was used as a reference, the local shell of the dome was selected as the target. The impact test was carried out in 15 working conditions by using the equivalent projectile freely fall- ing body to hit the target. Through the analysis of the experimental results, the 5 types of failure modes, i.e. im- pact crater, impact crack, impact spalling buckling, were calibrated and the characteristic form graph was impact penetration buckling and impact run through buckling provided. The penetration depth of impact run-through buck- ling failure was modified by introducing the thin steel plate ballistic limit velocity. A judgment standard of destruc- tion form was given out based on the ratio of penetration depth to dome thickness. At last, this paper puts forward the damage gradation standard of LNG tank dome under accidental impact load, and varifies effectiveness of the Pc- try formula and the BRL formula for penetration depth estimation.