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加筋圆柱壳水下爆炸动响应数值模拟 总被引:7,自引:0,他引:7
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. 相似文献
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《Marine Structures》2004,17(2):139-160
Profiled blast barriers are an integral part of offshore topsides where they are required to protect personnel and safety critical equipment against the effects of a possible hydrocarbon explosion. Limited studies on their response have been presented, particularly at high overpressures. This paper presents a numerical study using finite element analysis to investigate the response of stainless steel profiled barriers subjected to hydrocarbon explosions. By examining three profiles of varying depth (deep, intermediate and shallow) commonly used in offshore topside structures, the criteria governing their behaviour are highlighted. The static capacity and the dynamic response of the barriers are established up to the maximum capacity level and into the post peak or buckling response regime. The parameters that were found to have profound effects on the analyses include imperfections, boundary conditions and modelling assumptions. Through this study, recommendations and guidelines of using finite element analysis for the design or analysis of such explosion resistant barriers are given. 相似文献
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With the increasing applications in the offshore industry such as oil and gas jackets, submarine pipelines and wind turbine foundations, concrete-filled double skin steel tubular (CFDST) structures are encountering the ever-increasing risk of threats to underwater explosions (UNDEX). This study presents a systematical investigation on the structural behaviors and design recommendations of the CFDST structures subjected to UNDEX loadings through finite element analysis (FEA) approaches. Finite element models have been developed, where the non-linear material properties of the constitutive steel and concrete parts and the composite actions in-between have been considered. The FEA models are verified against the experimentally determined shock wave pressure history, the deformation shapes, and the residual strength. The full-range analyses were firstly carried out on the structural responses of CFDST structures, including the typical damage patterns and residual strength of the specimen after UNDEX. Then, the parametric studies show that the cross-section hollow ratio, charge weight, and explosion distance play great roles in determining the residual strengths. Thereafter, damage indexes considering the parameter of the hollow ratio and the scaled explosion distance has been formulated, and design recommendations have been suggested accordingly. 相似文献
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Gas explosions generally cause catastrophic damage to surrounding structures and humans. The application of blast wall can effectively prevent the damage. The uniform explosion load is widely used in assessing structural response, but it cannot represent the non-uniform characteristic of actual explosion pressures. The main contents of this paper are to study the effect of gas cloud characteristics on explosion pressure distribution, and analyze the effect of non-uniform loads on structural responses. The results reveal that the explosion loads have strongly spatial inhomogeneous when explosion scenarios have large sized cloud or long combustion distance. By establishing the overpressure-probability exceedance curves for uniform loading method and distributed loading method, based on the given accident frequency several design loads are determined. The structural responses of blast wall under design loads are assessed based on explosion evaluation acceptance criteria. It can be seen that the use of uniform loading method underestimates the structural response and misjudges the deformation pattern compared to actual explosion loads. Global and local explosion pressures should be considered simultaneously in the design specification. The overpressure-probability exceedance curves for non-uniform explosion pressures are recommended to establish the design load for blast wall. 相似文献
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舰船舷侧防护结构水下接触爆炸动响应分析研究 总被引:1,自引:0,他引:1
舰船舷侧防护结构在接触爆炸载荷作用下的动响应问题是舰船抗爆抗冲击设计的重要组成部分。根据国外水面舰船防护结构形式,在某单层舷侧舰船模型基础上增设舷侧防护隔壁结构,并应用国际上通用的动力有限元程序ABAQUS对其进行水下接触爆炸系列数值仿真实验,考核舷侧防护结构对舰船抗爆抗冲击性能的影响。通过结果的对比分析发现,增设舷侧防护结构后较明显改善了船体外板的损伤情况,且防护隔壁仅发生了少量的塑性变形没有产生破口,从而达到了保护内部机舱等重要舱室的目的,并以防护结构双层隔舱内填充液体抗冲击性能最佳。 相似文献
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Roughly 90% of all natural vibrations have epicenters in offshore zones and may cause destruction of submarine and floating structures. Such excitations can influence the safe performance of facilities set up on the seabed, like tunnels, jacket legs and subsea oil pipelines. Some researches on this theme have been carried out to demonstrate the importance of seaquake analyses and their effects have been underlined. The present study intends to numerically simulate a two-dimensional fluid-structure interaction (FSI) problem in order to examine the dynamic response of submarine tunnel under real horizontal earthquakes. Pressure is considered as independent nodal variables to represent the fluid flow effects and the induced time-dependent acceleration in porous medium equation is incorporated in the analysis and the tunnel shell is considered as flexible. This work highlights the importance of the input ground motion frequency content that governs the development of the induced seismic stress/strain around the lining of the tunnel. The results demonstrate that for deep sea the increment rate of the circumferential stress caused by surface gravity waves is below 7% when compared to the no-wave interface condition. Moreover, it is confirmed that long-period record may amplify the overall response of the system (up to 60%) specially the lateral and vertical displacements, as well as the principal stress to a lesser extent. The developed numerical model can attend to further analysis of tunnels embedded in a half-space in conjunction with fluid undergoing the severe long-period earthquakes. 相似文献
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某型舰船水下爆炸冲击波载荷作用下结构动态响应数值仿真研究 总被引:2,自引:0,他引:2
为保证舰船安全性,提高舰船生命力,舰船在水下爆炸冲击波载荷作用下动态响应,是船舶结构动力学研究的重要课题之一。采用MSC.DYTRAN有限元程序,运用数值仿真技术研究了某型水面舰船在水下爆炸冲击波载荷作用下的动态响应。分别从结构变形损伤、应力应变响应、变形能吸收和冲击环境等几个方面研究了舰船结构在水下爆炸冲击波载荷作用下的响应特性。 相似文献
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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. 相似文献