船舶力学
船舶力學
선박역학
JOURNAL OF SHIP MECHANICS
2014年
8期
940-957
,共18页
刘文玺%周其斗%张纬康%纪刚
劉文璽%週其鬥%張緯康%紀剛
류문새%주기두%장위강%기강
系泊系统%非线性有限元法%动力响应%耦合分析%高阶单元
繫泊繫統%非線性有限元法%動力響應%耦閤分析%高階單元
계박계통%비선성유한원법%동력향응%우합분석%고계단원
mooring system%nonlinear finite element method%dynamic response%coupled analysis%higher-order element
浮体与系泊系统的耦合动力分析对各种新型海洋平台和海洋结构物的应用具有重要意义。在浮体和系泊系统的时域耦合分析中,研究并提出了一种预报浮体和系泊系统非线性运动响应和缆索张力的分析技术。考虑瞬时物面变化引起的各种非线性因素,在时域内建立浮体的非线性运动方程并求解,其中,入射波力和静恢复力按瞬时物面条件计算,辐射力和绕射力按浮体在瞬时平均湿表面为平衡位置做简谐振荡运动来计算;考虑系泊缆索受到的非线性流体动力及大位移,采用三维弹性梁理论将缆索模型化,把缆索看作是等拉伸、等弯曲刚度的细长结构,并采用非线性有限元法对缆索的运动方程进行求解;将浮体的分析方法和系泊缆索的分析方法结合,建立了浮体和系泊系统非线性运动响应和缆索张力的耦合计算方法;对缆索,使用高阶单元,只需要较少的单元就可以得到收敛解;对耦合动力分析方程,采用隐式、显式混合的数值格式,最终将方程化为显式格式进行求解,并且合理排列和控制求解次序,这样大大提高了计算效率。对系泊浮体的固有周期、各种工况下大幅非线性运动、缆索张力等进行了计算,并进行对比研究,可以看出,该文的方法既适用于缆索小变形条件下,也适用于缆索大变形条件下浮体与系泊系统的耦合动力分析。
浮體與繫泊繫統的耦閤動力分析對各種新型海洋平檯和海洋結構物的應用具有重要意義。在浮體和繫泊繫統的時域耦閤分析中,研究併提齣瞭一種預報浮體和繫泊繫統非線性運動響應和纜索張力的分析技術。攷慮瞬時物麵變化引起的各種非線性因素,在時域內建立浮體的非線性運動方程併求解,其中,入射波力和靜恢複力按瞬時物麵條件計算,輻射力和繞射力按浮體在瞬時平均濕錶麵為平衡位置做簡諧振盪運動來計算;攷慮繫泊纜索受到的非線性流體動力及大位移,採用三維彈性樑理論將纜索模型化,把纜索看作是等拉伸、等彎麯剛度的細長結構,併採用非線性有限元法對纜索的運動方程進行求解;將浮體的分析方法和繫泊纜索的分析方法結閤,建立瞭浮體和繫泊繫統非線性運動響應和纜索張力的耦閤計算方法;對纜索,使用高階單元,隻需要較少的單元就可以得到收斂解;對耦閤動力分析方程,採用隱式、顯式混閤的數值格式,最終將方程化為顯式格式進行求解,併且閤理排列和控製求解次序,這樣大大提高瞭計算效率。對繫泊浮體的固有週期、各種工況下大幅非線性運動、纜索張力等進行瞭計算,併進行對比研究,可以看齣,該文的方法既適用于纜索小變形條件下,也適用于纜索大變形條件下浮體與繫泊繫統的耦閤動力分析。
부체여계박계통적우합동력분석대각충신형해양평태화해양결구물적응용구유중요의의。재부체화계박계통적시역우합분석중,연구병제출료일충예보부체화계박계통비선성운동향응화람색장력적분석기술。고필순시물면변화인기적각충비선성인소,재시역내건립부체적비선성운동방정병구해,기중,입사파력화정회복력안순시물면조건계산,복사력화요사력안부체재순시평균습표면위평형위치주간해진탕운동래계산;고필계박람색수도적비선성류체동력급대위이,채용삼유탄성량이론장람색모형화,파람색간작시등랍신、등만곡강도적세장결구,병채용비선성유한원법대람색적운동방정진행구해;장부체적분석방법화계박람색적분석방법결합,건립료부체화계박계통비선성운동향응화람색장력적우합계산방법;대람색,사용고계단원,지수요교소적단원취가이득도수렴해;대우합동력분석방정,채용은식、현식혼합적수치격식,최종장방정화위현식격식진행구해,병차합리배렬화공제구해차서,저양대대제고료계산효솔。대계박부체적고유주기、각충공황하대폭비선성운동、람색장력등진행료계산,병진행대비연구,가이간출,해문적방법기괄용우람색소변형조건하,야괄용우람색대변형조건하부체여계박계통적우합동력분석。
The analysis of the coupled floating body/mooring system is very important for the applying of new type of ocean structure. In time domain analysis of the coupled floating body/mooring system, a coupled analysis technology is developed for the forecasting of nonlinear motion responses and wave loads of float-ing body and mooring system. Considering the nonlinear factors resulting from considering the changing of transient body wetted surface, the nonlinear motion equations are built and solved in time domain. The in-cident wave force and hydrostatic restoring are calculated in transient body surface condition, while the diffraction force and radiation forces are calculated on the assume that the floating body oscillates around the balance situation which is the transient body wetted surface. The applied force on the rod comes from the nonlinear hydrodynamic force from surrouding fluid, and the geometric nonlinearity is considered. A three-dimensional elastic rod theory, which is extended to include the line stretching, is chosen to model-ing the mooring lines and risers. Finite element method is used to interpret the theory in a munerical form. Combining the analysis method for floating body and that for mooring lines, the coupled calculating method of nonlinear motion responses and mooring line tension for floating body and mooring lines is made. For the mooring lines, the higher-order element is used so that the quantity of elements is reduced greatly. For dy-namic analysis of the coupled system, in order to improve the computing efficiency, the integration, which is a mixture of implicit and explicit scheme, is developed, and so that the equations without explicit scheme is obtained, and the reasonable steps of computation are adopted. For the mooring floating body, all kinds of calculations are carried out, such as the natural periods, large amplitude nonlinear motion in all kinds of sea condition, mooring line tension, and so on, and at the same time comparisons among the results show that the analysis methods in this paper are fit not only for small amplitude motion but also large amplitude motion in time domain.