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世界上第一座采油平台建造于1947年,在美国的墨西哥湾,水深只有六公尺。25年来海上平台的建设得到了迅猛的发展,当前世界上已经建成了近一万座,水深也不断增加,突破了三百公尺大关。随着水深的增加,动力分析的重要性越来越突出了。平台承受的最主要的波浪载荷通常在5—15秒周期范围内为高能带,三百公尺水深的钢导管架(图1)平台的自然周期在5秒附近,正好靠近这个范围,因而造成动力放大。低于三百公尺的平台,只要它的自然周期离5秒不太远,也会有一定的动力放大,而每年数百万次的循环应力就会造成结构局部疲劳,土壤在长期循环应力作用下也有疲劳问题,会发生刚度退化导致平台的自然周期向波谱高能带漂移,使动响应进一步放大,造成恶性循环。所以平台结构动力分析的目
The world’s first oil production platform was built in 1947. In the United States, the Gulf of Mexico is only six meters deep. Over the past 25 years, the construction of the offshore platform has experienced rapid development. At present, there are nearly 10,000 built in the world, and the water depth has also increased continuously, breaking the 300-meter mark. As the water depth increases, the importance of dynamic analysis becomes more and more prominent. The most important wave load on the platform is usually a high energy band in the period of 5-15 seconds. The natural period of the platform of the 300-meter-thick steel jacket (Fig. 1) is near 5 seconds, which is close to this range. Power amplification. Platforms below 300 meters, as long as its natural cycle is not too far from 5 seconds, there will be a certain degree of power amplification, and millions of cycles of stress each year will cause structural fatigue, soil in the long-term cyclic stress There is also a fatigue problem under the effect, and the stiffness degradation will cause the natural period of the platform to shift to the high-energy band of the spectrum, which will further amplify the dynamic response and cause a vicious cycle. So the dynamics of platform structure analysis