Mechanical model and characteristics of deep-water drilling riser-wellhead system under internal solitary waves

Internal solitary waves with a huge amount of energy easily trigger the large dynamic responses of riser-wellhead system and threaten its structural safety. However, previous studies have only focused on the dynamic response of the riser under internal solitary waves. The riser may experience excessive traction from the platform, especially from the mooring platform, in response to the arrival of internal solitary waves. The bottom of the riser connects to the wellhead system, which in turn exerts a reaction force on the riser. To address this problem, a coupled dynamic model of deep-water drilling mooring platform-riser-wellhead system under internal solitary waves is developed in this paper. A dynamic response analysis method based on the fourth-order Runge-Kutta method and finite element method is also proposed for the mooring platform-riser-wellhead system. A dynamical solver for the coupled system is then developed using MATLAB. The dynamic response characteristics of the riser-wellhead system under internal solitary waves are calculated. Results show that the displacement and bending moment of the system initially increases and then decreases along with the propagation of internal solitary waves, and finally reach equilibrium position. The displacement and bending moment reach their peak before the trough of internal solitary waves passes through the riser-wellhead system. The dynamic responses of the riser-wellhead system under the influence of internal solitary wave loads are much larger than those without the effect of internal solitary wave loads. The riser system experiences shearing loads at the interface of internal solitary waves, which trigger a step-like bending moment variation. The bending moment of the conductor under the mudline is greatly increased by the internal solitary waves.     

基于 B/S 架构的汽车工程数据云平台的设计与实现

汽车产品开发愈发需要海量且高质量的基础数据作为支撑，汽车工程数据体系非常庞杂且彼此间关联度强，因此，针对汽车工程数据库开发，需站在汽车产品开发者和项目管理者角度为其提供更柔性化、可视化、深度化的数据服务。开发了高压缩比的图形引擎，并设计了一种基于 B/S 架构的汽车工程数据管理平台，以轻量化的三维模型为载体实现工程数据的强关联，较大程度地解决了汽车工程数据管理分散易丢失、完整性和一致性差、不易检索和无法进行数据挖掘等痛点问题，为汽车工程数据管理和重用提供了一个新的思路。     

VLEC B型舱5Ni钢免预热焊接工艺

针对原5Ni钢焊条焊前需要对钢板进行预热、生产效率相对较低的情况，在99 000 m3超大型乙烷运输船（Very Large Ethane Carrier，VLEC）B型舱建造过程中采用OK 92.55焊条和NI-C70S焊条进行5Ni钢焊接。经焊条性能、抗裂性和焊接工艺等试验研究，结果表明：两种焊条性能均满足规范要求，且抗裂性良好；在焊接参数处于合理范围内时，两种焊条均可在免预热钢板的情况下满足实船建造5Ni钢焊接接头的性能要求。