﻿ 舰船舱内空爆数值仿真方法研究
 舰船科学技术  2016, Vol. 38 Issue (11): 8-13 PDF

1. 海军驻中国舰船研究设计中心军事代表室, 湖北 武汉 430064 ;
2. 中国舰船研究设计中心, 湖北 武汉 430064 ;
3. 华中科技大学船舶与海洋工程学院, 湖北 武汉 430074

Numerical simulation method of vessel internal explosion
XIA Ji1, XIAO Han-lin2, ZHAO Cheng3, ZHANG Zhi-qiang3, LIU Tu-guang3
1. Naval Military Representative Office in China Ship Development and Design Center, Wuhan 430064, China ;
2. China Ship Development and Design Center, Wuhan 430064, China ;
3. Naval Architecture and Ocean Engineering, Hua zhong University of Sciences and Technology, Wuhan 430074, China
Abstract: Based on a vessel explosion experiment data, Ansys/LS-DYNA dynamic analysis software is used to simulate the vessel acceleration response of internal explosion. The finite element modeling is built in Ansys with Lagrange grid, TNT dynamite and air with Euler grid. The multi-material ALE algorithm is adopted in calculation. The effect of water field is replaced by added mass of entrained water. The results of shock wave simulations are compared with the classic experience formula and the reasonable grid division is given. Use simplified models to discuss the effect of boundary condition in acceleration to get more appropriate constraints. The analysis results show that it is feasible to use Ansys/LS-DYNA to simulate the impact environment in air and analyze the dynamic response of vessels under this situation, which can provide a basis for shock resistance of the vessels.
Key words: shock wave     acceleration response     blast shock wave     ALE algorithm     numerical simulation
0 引言

1 材料参数及有限元模型 1.1 模型材料参数

 ${P \!=\! A(1 - \frac{\omega }{{{R_1}V}}){e^{ - {R_1}V}} \!+\! B(1 - \frac{\omega }{{{R_2}V}}){e^{ - {R_2}V}} \!+\! \frac{{\omega E}}{V}}\text{，}$ (1)

 ${P \!=\! {C_0} \!+\! {C_1}\mu \!+\! {C_2}{\mu ^2} \!+\! {C_3}{\mu ^3} \!+\! ({C_4} \!+\! \\ {C_5}\mu \!+\! {C_6}{\mu ^2})E}\text{，}$ (2)

 $\sigma = (A + B{\overline \varepsilon ^p}^n)(1 + C\ln {\dot \varepsilon ^*})(1 - {T^*}^m)\text{，}$ (3)

1.2 有限元模型

 图 1 船体有限元模型示意图 Fig. 1 Finite element model of vessel

 图 2 空气流场有限元模型示意图 Fig. 2 Finite element model of air field
2 爆炸环境数值模拟 2.1 冲击波载荷模拟

 图 3 125 mm网格尺寸爆炸冲击波 Fig. 3 Shock wave of 125 mm grid

 图 4 75 mm网格尺寸爆炸冲击波 Fig. 4 Shock wave of 75 mm grid

 图 5 20 mm网格尺寸爆炸冲击波 Fig. 5 Shock wave of 20 mm grid

2.2 结构边界约束条件模拟

 图 6 约束条件简化模型 Fig. 6 Simplified model for constraint

 图 7 第1层平台加速度对比 Fig. 7 Acceleration of first platform

 图 8 第2层平台加速度对比 Fig. 8 Acceleration of second platform

 图 9 第4层平台加速度对比 Fig. 9 Acceleration of last platform

3 数值模拟计算结果

 图 10 观测点分布示意图 Fig. 10 Distribution of observation point

 图 11 上甲板加速度峰值分布 Fig. 11 Peak acceleration of upper deck

 图 12 下甲板加速度峰值分布 Fig. 12 Peak acceleration of lower deck

 图 13 一号平台加速度峰值分布 Fig. 13 Peak acceleration of platform 1

 图 14 龙骨加速度峰值分布 Fig. 14 Peak acceleration of keel

4 结语

1）对比经验公式超压值可得到不同炸药当量下合适的网格尺寸。20 mm网格尺寸可以较好地模拟120 kgTNT在空气中的爆炸冲击波，观测点超压误差在10%以内。

2）将船尾进行全约束和无约束边界条件对比可知，全约束的边界条件仅对约束附近加速度峰值有较大影响，其他部位两者加速度峰值基本一致，因此采用无约束边界条件与试验情况更为接近。

3）由数值仿真和实验测量加速度对比可知，在流场范围内观测点的仿真加速度峰值与实验加速度峰值误差较小，距离爆源较远处误差较大，这主要由于远处网格尺寸较粗糙导致的。

 [1] 张秀华, 张达.基于Euler算法的TNT炸药空中爆炸数值模拟研究[C]//第23届全国结构工程学术会议论文集.兰州:中国力学学会, 2014. ZHANG Xiu-hua, ZHANG Da. Blast shock wave characteristics and propagation law of internal gas explosion[C]//The Corpus of 23th National Structural Engineering Academic Meeting., Lanzhou: Chinese Society of Mechanics, 2014. [2] 孔祥韶, 吴卫国, 李晓彬, 等. 舰船舱室内部爆炸的数值模拟研究[J]. 中国舰船研究 , 2009, 4 (4) :7–11. KONG Xiang-shao, WU Wei-guo, LI Xiao-bin, et al. Numerical simulation of cabin structure under inner explosion[J]. Chinese Journal of Ship Research , 2009, 4 (4) :7–11. [3] 岳永威, 王超, 王奂钧. 计及水流场效应的军辅船空爆毁伤特性[J]. 舰船科学技术 , 2013, 35 (1) :16–21, 64. YUE Yong-wei, WANG Chao, WANG Huan-jun. Research on damage effect of military auxiliary vessels subject to the air explosion load considering water flow[J]. Ship Science and Technology , 2013, 35 (1) :16–21, 64. [4] 刘紫嫣, 王超, 岳永威, 等. 空爆载荷作用下舰船结构总强度分析[J]. 舰船科学技术 , 2012, 34 (12) :46–50. LIU Zi-yan, WANG Chao, YUE Yong-wei, et al. Total strength analysis of warship structure under air explosive load[J]. Ship Science and Technology , 2012, 34 (12) :46–50. [5] JOHNSON G R, COOK W H. A constitutive model and data for metals subjected to large strains, high strain rates and high temperatures[C]// Proceedings of the 7th International Symposium on Ballistics. Netherlands: The Hague, 1983. http://www.oalib.com/references/16161704 [6] 江帆.空爆载荷作用下舰船结构动态响应研究[D].哈尔滨:哈尔滨工业大学, 2011. JIANG Fan. Research on dynamic response of warship structure under explosion loading in the air[D]. Harbin: Harbin Engineering University, 2011. http://cdmd.cnki.com.cn/Article/CDMD-10217-1012264453.htm [7] 金咸定, 夏利娟. 船体振动学[M]. 上海: 上海交通大学出版社, 2011 . [8] LSTC. LS-DYNA keyword user's manual, version 971[Z]. LSTC, 2005. [9] 张社荣, 李宏璧, 王高辉, 等. 空中和水下爆炸冲击波数值模拟的网格尺寸效应对比分析[J]. 水利学报 , 2015, 46 (3) :298–306. ZHANG She-rong, LI Hong-bi, WANG Gao-hui, et al. Comparative analysis of mesh size effects on numerical simulation of shock wave in air blast and underwater explosion[J]. Journal of Hydraulic Engineering , 2015, 46 (3) :298–306. [10] 张秀华, 张达.基于Euler算法的TNT炸药空中爆炸数值模拟研究[C]//第23届全国结构工程学术会议论文集.兰州:中国力学学会, 2014. ZHANG Xiu-hua, ZHANG Da. Blast shock wave characteristics and propagation law of internal gas explosion[C]//The Corpus of 23th National Structural Engineering Academic Meeting., Lanzhou: Chinese Society of Mechanics, 2014. http://cpfd.cnki.com.cn/Article/CPFDTOTAL-LXFY201410003047.htm [11] 亨利其J.爆炸动力学及其应用[M].熊建国, 译.北京:科学出版社, 1987.