大型液化天然气储罐在冲击荷载下的动力响应数值研究（英文）

Numerical study on the dynamic response of a massive liquefied natural gas outer tank under impact loading

目的:研究冲击荷载各参数对于液化天然气(LNG)储罐的动力响应结果,定义LNG储罐受到冲击荷载时的破坏模式,并分析不同破坏模式下的破坏机理,为工程防御冲击荷载提供有效的理论研究基础。创新点:1.建立精细化的LNG储罐有限元模型;2.定义LNG储罐在冲击荷载下的破坏模式并揭示其破坏机理;3.提出损伤因子Df可区分三种冲击破坏模式。方法:1.通过有限元模拟,进行冲击荷载的参数分析,得到不同冲击荷载对于LNG储罐的动力响应(图6和7);2.根据数值模拟结果,定义LNG储罐受到冲击荷载时的破坏模式(图8),并分析其破坏机理(图10和11);3.通过经验公式验算LNG储罐抵御冲击荷载的可靠性。结论:1. LNG储罐薄弱部位为外罐和环梁及底板的连接部位;2. LNG储罐受到冲击荷载的破坏模式分为局部变形、混凝土剥落和穿透三种;本研究得到了各种破坏模式下的破坏机理,并定义了损伤因子Df来区分三种破坏模式;3.通过经验公式验算,LNG储罐可以抵御英国规范建议的冲击荷载和法兰的冲击;DOE-standard公式计算结果最为保守。

In this paper, the dynamic response of a typical 160 000 m3 liquefied natural gas(LNG) prestressed concrete outer tank under impact loading is investigated. The applicability of the Holmquist-Johnson-Cook(HJC) material model of concrete and numerical simulation method on impact that is proposed in this paper is verified by the test results of concrete slabs under projectile impact cited from the reference. A detailed finite element(FE) model of the LNG outer tank, including walls, buttresses, domes, beams, and bottom plates, under the impact of a Tomahawk cruise missile is established. In addition, pre-stress on the wall, impact angles, locations, and velocities are considered and their influence on dynamic response studied. The impact damage types for the LNG outer tank are concluded according to dynamic response results including stress, displacement, stress sweep range, and energy, and critical impact velocities to distinguish these damage types are also determined. In addition, the damage types and their failure mechanism are analyzed by the damage factor proposed in this paper, which is based on energy propagation. Finally, four empirical formulas of impact loading recommended by the standard "accident analysis for aircraft crash into hazardous facilities" are used for checking the impact resistance performance of the LNG outer tank and compared with FE numerical simulation results. It is demonstrated, by using empirical formulas, that the common 160 000 m3 LNG outer concrete tank could suffer flange impact loading. However, all the four empirical results were more conservative compared to numerical results under the same missile perforation velocity.