爆炸载荷下半潜式钻井平台月池结构动态响应

以某半潜式钻井平台月池结构为研究对象,基于一般耦合法建立拉格朗日与欧拉网格的耦合,计及应变率效应的影响,应用二阶精度求解器ROE算法结合等效当量TNT方法及理想气体状态方程,参考API规范要求设置多组计算工况,对月池结构在不同爆源高度及不同当量载荷下的动态响应进行了数值分析研究。研究发现：整体结构抗爆性能较好,未有结构发生破损失效。当爆源高度超过41.55m或当载荷增大时,对X方向月池内壁板格造成的冲击与变形损伤更大,该处结构在防爆设计时应重点考虑;平台沿Y方向的舱壁为主要吸能构件,占比最低为44.7%,当爆源高度降低时,吸能占比增加,当爆炸载荷增大时,吸能占比降低;沿X方向的舱壁吸能占比稳定约为24%。本文的研究对于评估平台结构抗爆性能,优化结构设计等方面具有一定的参考价值。     

番禺34-1CEP平台生活模块防爆墙结构强度分析

分析番禺34-1CEP平台生活模块防爆墙结构以及承受的爆炸载荷,分别应用静力和动力两种方法对防爆墙结构进行强度分析,通过分析比较两种计算结果,提出防爆墙结构强度计算方法的建议。     

Development of simplified method for prediction of structural response of stiffened plates under explosion loads

During their lifetime, marine structures may be exposed to accidental loadings such as from collisions or explosions, as well as environmental loadings such as from slamming, sloshing and green water. Such loadings can cause damage to structures. Therefore, to minimize such damage, advanced and robust design guidelines should be formulated. Among those loads, in this study, explosions imparting an impulsive pressure loading containing a rapid increase in pressure and a short duration that can cause serious casualties, property losses, and marine pollution were considered. In this paper, a practical and robust method for damage assessment of marine structures exposed to explosion loads based on a single degree of freedom (SDOF) system and numerical simulations is proposed. The SDOF method was improved by introduction of new and better idealization resistance for the system and consideration of the effect of strain-rate, and subsequently was verified by a numerical method developed using the commercial ABAQUS software package. The numerical method was itself validated by comparison with relevant pulse pressure test data available in the open literature (good correlation was shown). Based on the validated numerical models, a rigorous parametric study of the structural response of stiffened plates having actual scantlings of offshore structures was performed. The numerically obtained maximum deformations were compared with the results from the improved SDOF method in a parametric study, and the variation of both methods was verified. Finally, simple yet accurate and reliable formulations for prediction of structural response were empirically derived. These formulations are expected to be usefully employed as a first-hand tool for prediction of damage extent of marine structures (including offshore structures) due to explosion loads.     

典型舱内爆炸载荷对加筋板的毁伤特性

[目的]为研究典型舱内爆炸载荷对加筋板的毁伤特性,将舱内爆炸载荷分为初始爆炸冲击波载荷和准静态气压载荷,利用有限元分析软件LS-DYNA开展爆炸载荷下固支单向加筋板毁伤特性的数值模拟。[方法]主要模拟载荷冲量相等和载荷峰值相等时固支单向加筋板的变形特性,以及加筋板分别在初始爆炸冲击波载荷、准静态气压载荷及2种载荷联合作用下的毁伤特性,并分析上述载荷作用下加筋板的变形特点。[结果]结果表明:当作用在加筋板上的冲量相等、载荷作用时间小于0.05倍垂向一阶自振周期时,加筋板的最终挠度值处于最大值附近;当载荷峰值相同时,存在饱和冲量值,达到饱和冲量值以后,载荷作用时间不再影响加筋板的最终变形。[结论]在舱内爆炸载荷作用下,加筋板的最终变形不是2种载荷作用下的简单叠加,2种载荷的联合作用会增强毁伤效果。     

表征外部爆炸作用下舱段破坏的新型冲击因子研究

基于结构遮挡的冲击波能量提出了一种新型冲击因子.为验证该冲击因子在外部爆炸问题中的适用性,使用CONWEP算法对典型三舱段模型在不同装药工况下的响应进行非线性有限元数值仿真,并采用准静态法计算受损舱段的剩余极限强度.计算结果表明新型冲击因子相比传统冲击因子更适合用于表征外部爆炸作用下结构的整体破坏.对于远场爆炸工况,强力甲板最大位移、舱段塑形应变能和剩余极限强度在新型冲击因子衡量下均显示出较高的一致性.在近场爆炸工况中,由于结构局部变形的影响,计算结果存在一定的离散.     

Numerical prediction of wave-induced long-term extreme load effects in a flexible high-speed pentamaran

The theory and procedure established by Wu and Moan in 1996 and 2005 and Wu and Hermundstad in 2002 were applied to a high-speed transatlantic pentamaran containership. Nonlinear time-domain simulations of ship motions and load effects were carried out in different sea states. The simulated responses were validated against model tests with satisfactory results. The short-term probabilities of exceedance were estimated by using different stochastic analysis procedures. The long-term probabilities of exceedance were obtained based on the short-term results. These served as information about loading in a reliability-based design approach. The load effects in a semiprobabilistic design were also calculated at an appropriate probability of exceedance level.     

爆破边载对斜拉桥结构动力响应分析

施工爆破往往对既有临近建筑物的影响很大。针对这种边载效应可能造成的危害,结合爆破数值模拟中爆破荷载的特点,基于圣维南原理,将作用在炮孔壁上的爆破荷载等效后,施加在同排炮孔联心线或者面上,以模拟爆炸作用。采用三维实体模型等效模拟计算分析东海大桥在远场爆破施工对既有桥体结构稳定性的影响,计算结构不同位置、不同工况的振动响应和不同距离的最大单响药量,在此基础上,分析桥梁结构受爆破边载影响的危险区域,提出不同距离的药量控制,可为类似工程提供借鉴。     

可燃气体爆炸压力下海洋平台防爆墙数值仿真研究

采用等效TNT方法计算了海洋平台复杂结构在油气爆炸冲击波作用下的动态响应,采用多欧拉-拉格朗日耦合方法对三种不同防爆墙结构进行数值模拟研究.模拟结果显示:在油气爆炸冲击波的作用下,平台舱室变形、失效后破裂,冲击波通过破口传入平台其它舱室;对海洋平台爆炸舱室的围壁采用原结构、梯形结构和半椭圆三种防爆墙结构进行数值对比研究,考虑防爆墙的能量吸收和甲板能量吸收这两个方面,半椭圆防爆墙结构具有更好的防爆效果.     

水下爆炸作用下船舶结构与燃气轮机动态响应的数值研究

本文对水下爆炸作用下舰船结构及燃气轮机结构冲击响应进行了数值研究.首先,基于CEL方法建立了近自由面水下爆炸流固耦合动力学模型.然后结合燃气轮机-船体一体化仿真分析方法,对不同水下爆炸工况下的舰船结构冲击环境,以及燃气轮机冲击损伤特性进行了评估分析,总结了工况参数对燃气轮机冲击响应特征的影响规律,旨在为舰用燃气轮机抗冲击设计提供技术参考.     

加筋圆柱壳水下爆炸动响应数值模拟

圆柱壳是潜艇和海洋工程结构物广泛采用的结构单元,研究其水下爆炸动响应有助于深入了解圆柱壳结构的失效规律和机理,对于提高潜艇的生命力和战斗力有着重要的意义.本文首先研究了采用ABAQUS软件的水下爆炸载荷模型和计算参数的选取范围,然后选取加筋圆柱壳舱段为研究对象进行水下爆炸数值模拟,计算得出基座的冲击环境与试验数据吻合良好.本文进一步对圆柱壳在水下爆炸条件下的动响应规律进行了研究,得出了结构不同部位冲击动响应和冲击环境,并对不同部位冲击环境的差异进行了分析,得出了复杂圆柱壳结构在水下爆炸作用下的动响应和冲击环境规律.     

Dynamic response and performance of submarine tunnel subjected to surface explosions

Recently, external terrorist activities have become one of the most influential events on structural safety because of the absence of proper mechanisms to detect these events. In this study, the effects of surface explosions on the dynamic response and blast resistance of a submarine tunnel are investigated by using a coupled Lagrange and Euler (CLE) method. The feasibility and accuracy of the numerical method and material models are verified against the experimental data. After that, the numerical model is utilized to investigate the dynamic behavior and damage evolution of the submarine tunnel subjected to surface explosions. The dynamic behavior of the tunnel under various detonation scenarios in terms of the explosive weight and water depth is explored. Both the localized damage mechanism and the global structural response of the tunnel are examined. Empirical formulas are proposed to predict the failure modes of tunnel. Besides, studies of tunnel protection against potential attacks by using carbon fibre reinforced polymer (CFRP) and ultra-high performance concrete (UHPC) are also discussed. Numerical results in this study provide tunnel owners and engineers with thorough and important information on the structural performance of submarine tunnels subjected to blast loads, helping them in choosing effective protection strategies for potential explosion events.     

饱和冲量及其等效方法在舱室内爆炸中的应用

[目的]对于受到爆炸脉冲载荷冲击作用的船体结构,基于饱和冲量现象的相关研究表明,仅根据最大载荷幅值和脉冲总冲量来设计船体结构是不合理的,需探究工程应用中的饱和冲量现象。[方法]首先,总结饱和冲量概念的提出及研究发展;然后,以舱室内爆炸为典型算例,分析内爆炸载荷的曲线特性及结构响应特征;最后,基于饱和等效方法将复杂的内爆炸载荷等效为矩形脉冲载荷,采用理论及数值方法对等效载荷进行计算。[结果]结果表明:在舱室内爆炸准静态超压情况下普遍存在饱和冲量现象,实际工程应用中爆炸载荷会对结构造成较大的塑性变形,通常超过10倍板厚;而运用基于饱和冲量的等效方法分析,所得结果与数值仿真结果的误差小于10%。[结论]运用此方法可更准确地得出结构塑性动力响应结果,在结构抗冲击设计优化时,还可减少繁琐的复杂非线性数值计算,使设计更高效。     

圆筒型FPSO上部模块支撑结构疲劳分析

与船型FPSO相比,圆筒型FPSO没有明显的总纵弯曲,上部模块与船体结构之间通常采用刚性支墩来连接,水平运动所产生的弯矩和装/卸载引起的船体垂向变形对模块支撑结构的影响较为显著。因此,以“希望6号”圆筒型FPSO上部模块支撑结构为研究对象,基于DNVGL船级社规范,介绍一种简化疲劳分析方法。以FPSO运动加速度和船体变形载荷作为载荷输入条件,利用SESAM/GeniE软件进行有限元分析,得到结构在所有组合工况下应力的扫描计算结果。根据作业海域各个方向波浪发生的概率,运用简化疲劳分析方法计算得到所关注节点的疲劳损伤和各个工况对结构节点疲劳损伤度的贡献。结果表明,所关注节点的疲劳强度均满足设计疲劳强度要求;同一节点的疲劳损伤对不同浪向的敏感度不一样。该简化疲劳分析方法同样适用于承受周期性载荷的FPSO上部模块主结构和其他型式海洋结构物的疲劳分析。     

薄膜型LNG船全船结构屈服和疲劳强度分析

以某薄膜型液化天然气（Liquefied Natural Gas，LNG）船的结构设计为例，开展全船屈服强度校核和基于精细网格的有限元疲劳强度分析。针对5种典型装载状态，基于美国船级社（American Bureau of Shipping，ABS）全船强度直接计算指南，采用ABS-DLA/SFA系列软件，用三维波浪载荷预报程序对波浪随机载荷进行长期预报。基于预报结果，针对每种装载状态计算15个设计波参数组，求解全船结构在各载荷组合工况下的应力分布，继而完成屈服强度校核。以甲板机械室与穹顶甲板相交处的关键节点区域的节点设计为例开展细网格局部强度分析，并通过各种改进设计解决应力集中问题。针对2种常用典型操作装载状态及营运于北大西洋海区疲劳寿命满足40a的要求，基于ABS全船疲劳强度直接计算指南计算2个典型细化位置热点应力传递函数，通过谱分析得到疲劳累积损伤和疲劳寿命，完成疲劳强度校核。采用的全船强度和疲劳分析方法和思路适用于其他超大型船舶的结构分析。     

舰船板架在接触爆炸冲击载荷作用下的破坏

对舰船板架在接触爆炸载荷作用下的变形问题进行了研究.基于变分原理得到四边固支的板架残余变形的近似计算公式,根据破坏准则给出了估算破口半径的近似方法,并与经验公式进行了比较,结果基本上是合理的,可应用于舰船结构在爆炸冲击波作用下的毁伤或防护方面的工程预测,从而为舰船的安全防护设计提供理论依据.     

超大型矿砂船舱口盖载荷的局部强度分析

介绍了一艘超大型矿砂船在施加舱口盖载荷工况下,对相关的横向强框结构局部强度进行解析法分析。通过有限元法对强框处屈服、屈曲强度进行分析评估和理论验证。对比了国际船级社协会(IACS)《船舶结构强度》统一要求第21条(URS21)规定的舱口盖载荷均布施加于舱口围和实际集中载荷的四种不同工况下的结果 ,依据结果进行了结构合理加强。其分析结果与加强方案对超大型矿砂船局部强度分析具有一定的参考价值。     

Analysis of naval warship blast and shock resistance technology system北大核心CSCD

舰船抗爆和抗冲击技术概念宏观,内涵广泛,对其认识理解、设计研究都需要技术体系的顶层划分和牵引。首先,基于武器攻击对舰船的爆炸毁伤类型,对舰船抗爆与抗冲击这两个概念进行划分;然后,基于舰船总体抗爆抗冲击设计技术需求,区分不同的研究对象及技术的基础理论,提出包含6大类型的舰船抗爆抗冲击技术体系的划分方案,即水上/水下防护结构设计、新型抗爆结构与毁伤分析、设备系统及人员抗冲击、舰船抗爆抗冲击试验验证及技术标准规范;最后,分别对舰船抗爆和抗冲击技术内涵进行详细阐述。所做研究可为我国舰船抗爆抗冲击技术体系的形成提供一个初步构想,供从事舰船抗爆抗冲击设计、研究及管理人员参考。     

Equivalent design pressure for ship plates subjected to moving slamming impact loads

When a ship navigates at sea, the slamming impact can generate significant load pulses which move up along the hull plating. The effect of the moving pressure has so far not been explicitly considered in the Rules and Regulations for the Classification of Ships. Based on a modal superposition method and the Lagrange equation, this paper derives analytical solutions to study the elastic dynamic responses of fully clamped rectangular plates under moving pressure impact loads. The spatial variation of the moving slamming impact pressure is simplified to three types of impact loads, i.e. a rectangular pulse, a linearly decaying pulse and an exponentially decaying pulse. The dynamic responses of fully clamped rectangular plates under the moving slamming impact pressure are calculated in order to investigate the influence of the load pulse shapes and moving speed on the plate structural behaviour. It is found that the structural response of the plate increases with the increase of the moving speed. The response of the plate subjected to a moving pressure impact load is smaller than the case when the plate is subjected to a spatially uniform distributed impact load with the same load amplitude and load duration. In order to quantify the effect of the moving speed on the dynamic load, a Dynamic Moving Load Coefficient (DMLC) is introduced as the ratio between the dynamic load factor for the moving impact load and that under the spatially uniform distributed impact load. An expression for DMLC is proposed based on analyses of various scenarios using the developed analytical model. Finally an empirical formula which transforms the moving impact loads to an equivalent static load is proposed.     

Blast loaded plates

Plates form one of the basic elements of structures. Land-based structures may be subjected to air blast loads during combat environment or terrorist attack, while marine structures may be subjected to either air blast by the attack of a missile above the water surface or an underwater explosion by the attack of a torpedo or a mine or a depth charge and an aircraft structure may be subjected to an in-flight attack by on-board explosive devices. Furthermore, gas explosion occurs in offshore installations and industries. This review focuses on the phenomenological evolution of blast damage of plates.     

变刚度楔形体板架落体砰击试验研究

通过对具有四种刚度的两个二维楔形体板架的自由落体试验,测量模型入水速度、砰击压力和结构响应,获得模型底部板架在砰击载荷作用下的响应特征;对结构模型在均布静压力作用下的应力响应进行结构力学分析;比较试验和计算得到的应力响应,获得作用在模型肋骨上的砰击压力的折减系数,从而使该结构在设计时仍可按常规的静力计算方法进行强度校核。通过试验,深入研究了折减系数与结构刚度的关系,并指出在船体局部结构设计中应充分注意刚度变化对折减系数的影响。