船体局部结构在砰击载荷作用下动响应的数值仿真研究
|
摘要
船舶在恶劣的海况中航行时,会伴随着剧烈的升沉和纵摇运动,当船体出水后再入水时极易发生砰击现象。砰击会造成局部结构破坏,同时也能引起船体梁的弹性振动,威胁船舶的总纵强度安全。随着船舶的大型化和高速化,砰击问题变得更易发生且对船体结构的危害也愈大。砰击载荷是船舶波浪载荷的重要组成部分,各大船级社已将船体结构在砰击载荷作用下的强度安全作为衡量船舶安全的标准之一。
本文以Wagner的入水砰击理论为指导,使用MSC.DYTRAN瞬态动力学分析软件模拟结构入水砰击过程。首先,对刚性楔形体的入水砰击进行仿真模拟,将斜升角为30o的楔形体落水过程中受到的砰击力和运动速度与Zhao的试验结果进行对比,两者吻合较好,从而验证了该仿真方法的可行性和计算精度;其次,改变楔形体的斜升角和入水速度,进行参数敏感性分析,得到砰击压力系数与斜升角的关系曲线,其与Wagner的理论值和Chuang的试验值具有可比性,并对砰击压力在楔形体底面的时间分布规律进行了研究;最后,建立平底加筋板的模型,模拟弹性体的入水砰击过程。通过对比弹性体和刚性体的入水砰击载荷,表明弹性效应的存在降低了砰击载荷的峰值,且入水速度越大,弹性效应越明显。改变结构的底板厚度和入水速度进行敏感性分析,得到结构响应随上述参数改变的变化规律。
When the ship is navigating in adverse conditions, slamming is easily occurred when the hull reenter the water because of the severe heave and pitch motion. Slamming will result in local structural damage and the elastic vibration of hull girder which will threaten the ship’s longitudinal strength security. With the ship’s large scale and high speed, slamming is becoming more susceptible and greater harm to the ship structure. Slamming loads is an important part of wave loads, and the intensity security under slamming loads has been seen as one of the ship safety standards by major classification societies.
In this paper, the Wager’s theory is seen as a guide, and the transient dynamic analysis software which called MSC.DYTRAN is used to simulate the process of slamming into the water. First, the slamming process of rigid wedge is simulated, and the slamming force and velocity of the wedge which ramp angle is 30 degrees were compared with Zhao’s experimental results, both in good agreement, which verifies the feasibility of the simulation method and precision. Second, the ramp angle and velocity were changed and parameter sensitivity was analyzed, slamming pressure coefficient was derived and compared with Wagner’s theory result and Chuang’s experiment result, and the spatial distribution of slamming pressure was studied. Finally, a flat stiffened plate model was modeled to simulate the elastic body slamming. By comparing the slamming loads of elastic and rigid body and indicated that the presence of elastic effect reduce the peak value of slamming loads, and the greater the speed, flexibility was more obvious. Change the speed and base plate thickness of the flat panel, parameter sensitivity was analyzed and the structural response with these parameters was obtained.
本文以Wagner的入水砰击理论为指导,使用MSC.DYTRAN瞬态动力学分析软件模拟结构入水砰击过程。首先,对刚性楔形体的入水砰击进行仿真模拟,将斜升角为30o的楔形体落水过程中受到的砰击力和运动速度与Zhao的试验结果进行对比,两者吻合较好,从而验证了该仿真方法的可行性和计算精度;其次,改变楔形体的斜升角和入水速度,进行参数敏感性分析,得到砰击压力系数与斜升角的关系曲线,其与Wagner的理论值和Chuang的试验值具有可比性,并对砰击压力在楔形体底面的时间分布规律进行了研究;最后,建立平底加筋板的模型,模拟弹性体的入水砰击过程。通过对比弹性体和刚性体的入水砰击载荷,表明弹性效应的存在降低了砰击载荷的峰值,且入水速度越大,弹性效应越明显。改变结构的底板厚度和入水速度进行敏感性分析,得到结构响应随上述参数改变的变化规律。
When the ship is navigating in adverse conditions, slamming is easily occurred when the hull reenter the water because of the severe heave and pitch motion. Slamming will result in local structural damage and the elastic vibration of hull girder which will threaten the ship’s longitudinal strength security. With the ship’s large scale and high speed, slamming is becoming more susceptible and greater harm to the ship structure. Slamming loads is an important part of wave loads, and the intensity security under slamming loads has been seen as one of the ship safety standards by major classification societies.
In this paper, the Wager’s theory is seen as a guide, and the transient dynamic analysis software which called MSC.DYTRAN is used to simulate the process of slamming into the water. First, the slamming process of rigid wedge is simulated, and the slamming force and velocity of the wedge which ramp angle is 30 degrees were compared with Zhao’s experimental results, both in good agreement, which verifies the feasibility of the simulation method and precision. Second, the ramp angle and velocity were changed and parameter sensitivity was analyzed, slamming pressure coefficient was derived and compared with Wagner’s theory result and Chuang’s experiment result, and the spatial distribution of slamming pressure was studied. Finally, a flat stiffened plate model was modeled to simulate the elastic body slamming. By comparing the slamming loads of elastic and rigid body and indicated that the presence of elastic effect reduce the peak value of slamming loads, and the greater the speed, flexibility was more obvious. Change the speed and base plate thickness of the flat panel, parameter sensitivity was analyzed and the structural response with these parameters was obtained.
引文
[1]骆寒冰,舰船尾砰击颤振响应的试验及理论预报研究,博士学位论文,中国船舶科学研究中心,2007,1
[2]陈震,海洋结构物入水砰击载荷与响应研究,博士学位论文,上海交通大学,2005
[3] Gil Wittlin, Mike Schultz, Michael R Smith, Rotary Wing Aircraft Water Impact Test And Analyses Correlation, American Helicopter Society 56th Annual Forum, 2000
[4]戴仰山,沈进威,宋竞正,船舶波浪载荷,北京:国防工业出版社,2007
[5]骆寒冰,徐慧,余建星等,舰船砰击载荷及结构动响应研究综述,船舶力学,2010,14,4
[6] Von Karman T. The impact on seaplane floats during landing[R]. National Advisory Committee for Aeronatics. Techinical note No.321, 1932: 309-313
[7] Wagner, H. Phenomena associated with impacts and sliding on liquid surfaces[J]. ZAMM, 1932, 12, 4, 193-235
[8] Zhao, R., Faltinsen, O.M. Water Entry of Two-Dimensional Bodies[J]. Journal of Fluid Mechanics, 1993, Vol. 246, 593-612
[9] Chuang, S.L. Analytical Determination of Slamming Pressures for High Speed Vessels in Waves[J]. Journal of Ship Research, 1976, Vol. 20, 190-198
[10] Zhao, R., Faltinsen, O.M. and Aarsnes, J.V. Water entry of arbitrary two-dimensional sections with and without flow separation[C]. Proc. 21st Symposium on Naval Hydrodynamics, 1996, 408-423
[11]陈震,肖熙.二维楔形体入水砰击仿真研究[J].上海交通大学学报, 2007.41(9),14,25-28
[12] Faltinsen, O.M. Water entry of a wedge by hydroelastic orthotropic plate theory[J]. J. ship Res. 1999, 43, 180-193
[13]卢炽华,何友声.二维弹性结构入水冲击过程中的流固耦合效应[J].力学学报, 2000,32(2),129-140
[14]孙辉,卢炽华,何友声.二维楔形体冲击入水时的流固耦合响应的实验研究[J].水动力研究与进展, 2003,Ser.A,18(1),1-6
[15] N.Aquelet, M. Souli, L. Olovsson. Euler-Lagange coupling with damping effects: Application to slamming problems[J]. Comput. Methods appl. Mech. Engrg. 2006, 195,110-132
[16]曹正林,高速三体船砰击强度研究,博士学位论文,武汉理工大学,2008
[17]中华人民共和国国家军用标准GJB4000-2000.水面舰船结构设计技术方法[S].2000
[18] Lloyd’s Register Rules and regulations for the classification of naval ships[S].2005
[19] Common Structure Rules for Bulk Carriers. 2009
[20] Common Structure Rules for Double Hull Oil Tankers. 2009
[21] Rules for Building and Classing of American bureau of Shipping.2009
[22]中国船级社,钢制海船入级规范,北京:2006
[23]丁沛然,钱纯,非线性瞬态动力学分析MSC.Dytran理论及应用,北京,科学出版社,2006,1~2
[24]马爱军,周传月,王旭,Patran和Nastran有限元分析专业教程,北京,清华大学出版社,2005
[25]卞文杰,万历,吴莘馨,瞬态动力学CAE解决方案MSC.Dytran基础教程,北京,北京大学出版社,2004,4~15
[26]丁沛然,钱纯,非线性瞬态动力学分析MSC.Dytran理论及应用,北京,科学出版社,2006,155~156
[27] Alex W.Vredeveldt, Hydrodynamic Impact Response, A Flexible View, Fast, 2001
[2]陈震,海洋结构物入水砰击载荷与响应研究,博士学位论文,上海交通大学,2005
[3] Gil Wittlin, Mike Schultz, Michael R Smith, Rotary Wing Aircraft Water Impact Test And Analyses Correlation, American Helicopter Society 56th Annual Forum, 2000
[4]戴仰山,沈进威,宋竞正,船舶波浪载荷,北京:国防工业出版社,2007
[5]骆寒冰,徐慧,余建星等,舰船砰击载荷及结构动响应研究综述,船舶力学,2010,14,4
[6] Von Karman T. The impact on seaplane floats during landing[R]. National Advisory Committee for Aeronatics. Techinical note No.321, 1932: 309-313
[7] Wagner, H. Phenomena associated with impacts and sliding on liquid surfaces[J]. ZAMM, 1932, 12, 4, 193-235
[8] Zhao, R., Faltinsen, O.M. Water Entry of Two-Dimensional Bodies[J]. Journal of Fluid Mechanics, 1993, Vol. 246, 593-612
[9] Chuang, S.L. Analytical Determination of Slamming Pressures for High Speed Vessels in Waves[J]. Journal of Ship Research, 1976, Vol. 20, 190-198
[10] Zhao, R., Faltinsen, O.M. and Aarsnes, J.V. Water entry of arbitrary two-dimensional sections with and without flow separation[C]. Proc. 21st Symposium on Naval Hydrodynamics, 1996, 408-423
[11]陈震,肖熙.二维楔形体入水砰击仿真研究[J].上海交通大学学报, 2007.41(9),14,25-28
[12] Faltinsen, O.M. Water entry of a wedge by hydroelastic orthotropic plate theory[J]. J. ship Res. 1999, 43, 180-193
[13]卢炽华,何友声.二维弹性结构入水冲击过程中的流固耦合效应[J].力学学报, 2000,32(2),129-140
[14]孙辉,卢炽华,何友声.二维楔形体冲击入水时的流固耦合响应的实验研究[J].水动力研究与进展, 2003,Ser.A,18(1),1-6
[15] N.Aquelet, M. Souli, L. Olovsson. Euler-Lagange coupling with damping effects: Application to slamming problems[J]. Comput. Methods appl. Mech. Engrg. 2006, 195,110-132
[16]曹正林,高速三体船砰击强度研究,博士学位论文,武汉理工大学,2008
[17]中华人民共和国国家军用标准GJB4000-2000.水面舰船结构设计技术方法[S].2000
[18] Lloyd’s Register Rules and regulations for the classification of naval ships[S].2005
[19] Common Structure Rules for Bulk Carriers. 2009
[20] Common Structure Rules for Double Hull Oil Tankers. 2009
[21] Rules for Building and Classing of American bureau of Shipping.2009
[22]中国船级社,钢制海船入级规范,北京:2006
[23]丁沛然,钱纯,非线性瞬态动力学分析MSC.Dytran理论及应用,北京,科学出版社,2006,1~2
[24]马爱军,周传月,王旭,Patran和Nastran有限元分析专业教程,北京,清华大学出版社,2005
[25]卞文杰,万历,吴莘馨,瞬态动力学CAE解决方案MSC.Dytran基础教程,北京,北京大学出版社,2004,4~15
[26]丁沛然,钱纯,非线性瞬态动力学分析MSC.Dytran理论及应用,北京,科学出版社,2006,155~156
[27] Alex W.Vredeveldt, Hydrodynamic Impact Response, A Flexible View, Fast, 2001