共查询到19条相似文献，搜索用时 109 毫秒
1.
锥体导管架海洋平台冰激振动的DEM-FEM耦合分析及高性能算法 总被引：1，自引：0，他引：1
在寒区海域,冰荷载是影响海洋平台安全运行的主要环境荷载之一,由其引起的冰激振动给平台结构及其上部设备带来了严重危害。为分析不同冰况下平台的振动响应,本文建立了导管架海洋平台冰激振动的离散元（DEM）-有限元（FEM）耦合模型。采用具有黏接-破碎性能的等粒径球体离散单元对海冰的破碎特性进行模拟,通过由梁单元构建的海洋平台有限元模型获得结构的振动响应。在离散元与有限元的接触区域中实现了两个模型间计算参数的传递。为提高该耦合模型的计算效率和规模,发展了基于动力子结构方法的DEM-FEM耦合模型。为验证该耦合模型的有效性和可行性,将不同冰况下得到的冰荷载与ISO19906和JTS 144-1-2010标准进行了对比。结果表明,计算得到的冰荷载与标准相近,且冰厚与冰荷载呈二次非线性关系。同时,从冰速和冰厚两方面对比了渤海四桩腿JZ20-2 MUQ锥体导管架平台冰激振动加速度的数值结果和现场实测数据,发现冰速与振动加速度呈线性关系,冰厚与振动加速度呈二次非线性关系,并且振动加速度与冰速和冰厚平方的乘积呈线性关系。 相似文献
2.
导管架平台安装锥体降低冰振效果研究 总被引：1，自引：0，他引：1
冰荷载是寒区海洋结构的控制荷载.在圆柱结构上安装锥体用以降低极值冰力,这一概念已得到理论与模型实验的验证,但是安装锥体对降低结构冰激振动的效果还没有得到充分论证.首先分析和比较了圆柱结构和加锥结构的交变冰力与冰振响应形式.基于现场原型监测系统的实测数据,无论是圆柱结构和加锥结构都能发生强烈的冰激振动,圆柱结构上的稳态冰激振动最为严重.通过一座单腿圆柱结构加装锥体前后的冰振响应监测和分析,得到安装破冰锥体对降低冰振的实际效果.理论分析和实测数据表明,破冰锥体从根本上避免了冰激结构稳态振动的发生. 相似文献
3.
4.
5.
应用ANSYS软件建立了平台和冰相互作用的有限元模型,构建了自升式平台的冰激振动模型,并计算基于2种冰力模型的自升式平台的动力响应。此动力分析方法具有建模方便和计算精度高的特点。以某自升式平台为例,计算了冰和平台结构相互作用的耦合效应,为自升式平台冰激振动安全评估提供了参考依据。 相似文献
6.
自升式钻井平台在设计时通常不考虑冰荷载的作用,要实现冰区作业,首先需要对该类平台的抗冰能力进行准确评估。本文通过开展冰池试验,对自升式钻井平台冰载荷作用机理、结构冰激特性以及抗冰方法等进行研究。海洋结构受到的冰荷载大小以及结构响应值与冰厚密切相关,冰激振动机理与冰厚无关,探究不同冰速和冰厚下冰荷载及振动响应的时程曲线,可发现低冰速下结构展现出的准静态响应特征以及高冰速下的随机响应特征。冰激振动的发生是结构固有特性、冰速、冰厚、冰材料参数等因素共同影响的结果,其作用机理尤为复杂,本研究侧重于桁架式自升式平台冰区作业中结构冰激振动特性研究。 相似文献
7.
8.
《海洋技术学报》2018,(5)
损伤识别是海洋平台结构健康监测的核心问题,对于保障结构的安全服役具有重要的意义。文中将交叉模型交叉模态(CMCM)有限元模型修正方法应用到了导管架式海洋平台结构的损伤识别中。针对实测模态含噪声条件下该方法遇到的"病态"求解难题,引入了截断奇异值分解正则化方法,提出了基于正则化模型修正的损伤识别过程。为验证该过程的有效性,制做了某导管架平台的钢质缩尺简化模型,并在两个典型构件处设置了损伤;利用冲击激励对结构进行了振动测试;根据模态识别结果,采用正则化模型修正过程对各损伤工况进行了损伤识别。结果表明,利用有限的低阶含噪声模态,借助正则化求解技术,该模型修正方法可有效地识别导管架平台结构的损伤。 相似文献
9.
10.
海洋平台随机冰力谱的识别 总被引：5，自引：2，他引：3
将海冰对结构的作用看作是随机激励,利用海洋平台原型结构冰激振动的实测响应数据,用逆虚拟激励法(1PEM)识别了平台的冰载荷谱,结果表明逆虚拟激励法识别效果满足工程实际的需要,有较好的应用前景。 相似文献
11.
基于海冰区划的平台结构振动舒适度设计--容许加速度限值 总被引：1，自引：0，他引：1
海冰作用下平台结构的振动舒适度是冰区导管架平台结构设计需要考虑的重要问题，传统的单一界限方法由于不能考虑冰期的长短和冰情出现概率，从而导致了不同冰区平台结构具有不同的振动舒适度水平。引入了对振动舒适度进行量化的烦恼率模型，结合冰期和冰情出现概率，给出了不同冰期和冰情出现概率下结构容许振动加速度的确定方法。结合我国渤海的海冰区划，给出了不同冰区结构容许振动加速度值。 相似文献
12.
针对渤海湾某风电场的海上固定式风机支撑结构,采用适用于大直径单桩结构的PSI曲线模拟桩土相互作用,并采用SACS软件建立支撑结构的动力分析模型。首先对支撑结构进行模态分析;其次考虑海冰结构的随机振动作用模式,根据适用于渤海湾的随机冰力谱构造随机冰载荷时程曲线,基于半耦合的时域方法,采用SACS软件对支撑结构进行冰激振动分析,输出塔筒顶部加速度、单桩基底剪力及倾覆力矩等响应参数的时程曲线和响应功率谱;最后针对冰厚、冰速和海冰强度等海冰参数对支撑结构的冰激振动进行敏感性分析。研究结果表明,在随机振动模式下,冰载荷及结构动力响应对冰厚和海冰强度较为敏感,在进行冰激振动分析时应合理确定冰厚和海冰强度等参数。 相似文献
13.
在海洋平台摇摆墙体系基础上,提出在海洋平台和摇摆墙之间刚性连接杆的铰接点处安装粘弹性转角阻尼器的减振措施,对海洋平台进行进一步减振控制。对粘弹性转角位移阻尼器的刚度和阻尼参数进行了优化分析,可知阻尼器的阻尼与刚度在结构减振中起到了十分重要的作用,且存在特定范围内的优化值。以JZ20-2北高点井口平台为例,利用ANSYS进行地震荷载作用和实测挤压冰荷载下的仿真分析,研究了粘弹性转角阻尼器在海洋平台和摇摆墙之间刚性连接杆铰接点处的不同安装方式,对比分析减振效果。结果表明,在该体系刚性连接杆的铰接点处安装粘弹性转角阻尼器能显著降低结构的振动反应,连接杆右侧安装粘弹性转角阻尼器的方式为减振效果最佳方式。 相似文献
14.
The problems of ice-induced vibration have been noticed and concerned since the 1960s, but it has not been well resolved. One reason is that the dynamic interaction between ice and structure is so complicated that practical ice force model has not been developed. The recent full-scale tests conducted on jacket platforms in the Bohai Sea presented that ice could cause intense vibrations which endanger the facilities on the deck and make discomfort for the crew. In this paper, the strategy of mitigation of ice-induced offshore structure vibration is discussed. Based on field observations and understanding of the interaction between ice and structure, the absorption mitigation method to suppress ice-induced vibration is presented. The numerical simulations were conducted for a simplified model of platform attached with a Tuned Mass Danlper （TMD） under ice force function and ice force time history. The simulation results show that TMD can fa- vorably reduce ice-induced vibrations, therefore, it can be considered to be an alternative approach to utilize. Finally, the application possibilities of utilizing TMDs on other miniature offshore structures in ice-covered areas of marginal oil fields are discussed. 相似文献
15.
16.
17.
Yongjun Xu Yubiao Liu Changzhen Kan Zhonghan Shen Zhongmin Shi 《Ocean Engineering》2009,36(8):588-594
Jacket platform is the most widely used offshore platform. Steel rubber vibration isolator and damping isolation system are often used to reduce or isolate the ice-induced and seismic-induced vibrations. The previous experimental and theoretical studies concern mostly with dynamic properties, vibration isolation schemes and vibration-reduction effectiveness analysis. In this paper, the experiments on steel rubber vibration isolator were carried out to investigate the compressive properties and fatigue properties in different low temperature conditions. The results may provide some guidelines for design of steel rubber vibration isolator for offshore platform in a cold environment, and for maintenance and replacement of steel rubber vibration isolator, and also for fatigue life assessment of the steel rubber vibration isolator. 相似文献
18.
Time- and Frequency-Domain Analysis of Ice-Induced Displacement Responses of Offshore Fixed Platforms 总被引：1，自引：0，他引：1
GAO Zhaojie DUAN Menglan Senior Engineer China Classification Society Beijing P. R. China. 《中国海洋工程》1998,(4)
—On the basis of ice-induced forced vibration model,ice-induced displacement responses ofoffshore fixed platforms are investigated in both time domain and frequency domain.The relationships ofice-induced displacement responses with ice breaking modes,ice acting directions and platform structuresare analyzed and determined.The results lead to an important conclusion obtained for the first time thatice breaking frequency and the natural frequency of the first mode of the platform are the two main fac-tors that dominate the degree of vibration.The present work provides a firm basis for both design and op-eration of fixed platforms against ice loading. 相似文献
19.
Chen Xueming Li Longyuan Wang Qinjian
Senior Engineer Dept. of Naval Arch and Ocean Engineering Shanghai Jiaotong University Shanghai .
Senior Engineer Bohai Oil Engineering Design Company 《中国海洋工程》1996,(4)
Based on the Bohai ocean environment characteristics, a new platform vibration distribution structure is designed to reduce the platform vibration due to flowing ice. The effect of the earthquake wave and ocean wave load on this vibration distribution structure is considered in the design. The principal idea of this new vibration distribution structure is dividing the platform main column into the inner tube and the outer tube. The outer tube is connected with the leg pontoon by braces, while the inner tube is used to support the platform deck. The inner tube and outer tube can be connected or disconneted in the region near the water line. For evaluating the vibration reduction effect of such a structure, tests are carried out on a steel model, and the external load of flowing ice, earthquake wave and ocean wave are simulated by concentated random load applied to different points of the model. The tests are performed in water media and air media respectively. The vibration reduction effect is evaluated 相似文献