CN105711763A - Typhoon load calculation method for ocean platform topside block - Google Patents

Abstract

The invention relates to a typhoon load calculation method for an ocean platform topside block. The typhoon load calculation method comprises the following steps: dispersing an around part of a tension leg platform topside block into micro elements along an axis; acquiring a tangential typhoon speed and a radial speed to structural micro elements according to distribution of the tangential speed and the radial speed of typhoon; decomposing the tangential speed and the radial speed so as to obtain a global coordinate system; according to a moving speed of a platform self and the air speed, calculating a relative speed of a platform structure and typhoon; converting the relative speed into a normal relative speed perpendicular to the axis; converting the normal relative speed into a body axis coordinate system from the global coordinate system; counting wind load pointing to an inner normal direction of the side wall of the topside block; converting the wind load into the global coordinate system from the body axis coordinate system, thereby obtaining typhoon load of the whole topside block. By adoption of the typhoon load calculation method, typhoon load can be rapidly and conveniently calculated, and scientific technical support can be provided for prevention of accidents that the tension leg platform is turned over under the action of extreme typhoon load.

Description

Ocean platform upper chunk typhoon load calculation method

Technical field

The invention belongs to field of ocean engineering, be a kind of quick calculation method of typhoon load suffered by large scale ocean engineering structure.

Background technology

World ocean petroleum resource cities accounts for the 34% of Global Oil total resources, global ocean reserves of oil amount about 100,000,000,000 tons, and wherein proved reserves is 38,000,000,000 tons.Continually developing application along with the progress of technology and new technologies and materials, the cost of offshore oil exploration and exploitation lowers year by year, has promoted the development of marine petroleum development.

China's offshore petroleum resources are quite abundant, and only marine oil and gas reserves in the South Sea are tentatively explored is 230 hundred million to 300 hundred million tons, therefore develop the offshore oil at the South Sea to promoting that national economic development has great significance.

South Sea marine environment is severe.The number of times that annual typhoon occurs is typically in 6,7 times, and the blast of Typhoon-Induced and billow act on ocean structure, and especially the superstructure module of marine oil and gas platform, suffers platform wind action, causes that production of hydrocarbons platform destroys.

One of main form of platform of deep-sea oil gas exploitation is tension leg platform (TLP), is operated in the tension leg platform (TLP) in U.S. Mexico gulf, the major accident under typhoon effect once occurred, and tension leg platform (TLP) is by typhoon smashed.

Due to tension leg platform (TLP) upper chunk bulky, typhoon cyclone causes torsion and the push-and-pull of superstructure chunk, causes platform in balance position change and reverse.Additionally, the wind direction of typhoon velocity field can produce instantaneous change with the mobile of center of typhoon, the calculating of its load can not adopt the Steady Wind model that people know well.The dynamic response of the load how calculating typhoon cyclone and the structure caused, lacks effective computational methods at present both at home and abroad.In order to solve the calculating that under typhoon effect, deep-sea tension leg platform (TLP) is loaded, the dynamic response that forecast typhoon cyclone causes, make this invention.The present invention is directed to the upper chunk of deep-sea tension leg platform (TLP), it is proposed that the computational methods that typhoon load is fast and convenient, compensate for the research of tension leg platform (TLP) upper chunk typhoon LOAD FOR blank.

Summary of the invention

It is an object of the invention to provide a kind of fast and convenient typhoon load calculation method, effectively obtain the wind load of tension leg platform (TLP) upper chunk under typhoon effect, it is possible to for avoiding the accidents such as tension leg platform (TLP) topples under typhoon extreme loads effect to provide the technical support of science.

The tension leg platform (TLP) upper chunk typhoon load calculation method step of present invention exploitation is as follows:

Step 1: take the peripheral portion of tension leg platform (TLP) upper chunk, namely end to end cuboid, it is separated into infinitesimal along axis.

Step 2: be distributed according to the tangential velocity of typhoon and radial velocity, obtains the typhoon tangential velocity suffered by structure infinitesimal and radial direction wind speed.

Step 3: tangential wind speed and radial direction wind speed are decomposed global coordinate system, obtains x and the axial wind speed of y-coordinate.

Step 4: according to the movement velocity of platform self and wind speed, obtain the relative velocity of platform structure and typhoon.

Step 5: relative velocity is converted into the normal direction relative velocity vertical with axis.

Step 6: normal direction relative velocity is transformed into satellite coordinate system from global coordinate system.

Step 7: count the wind load pointing to upper chunk sidewall inter normal direction.

Step 8: by wind load from satellite ordinate transform to global coordinate system.

Step 9: wind load suffered by each infinitesimal is integrated, obtains wind load suffered by whole upper chunk.

The outstanding advantages of the present invention is:

1, the typhoon load calculation method of the present invention is simple, efficient, feasible.

2, can according to wind load suffered by calculated tension leg platform (TLP) upper chunk, it is possible to tension leg platform (TLP) is carried out motion response forecast, optimize exercise performance and the structural strength of tension leg platform (TLP) further.

Accompanying drawing explanation

Fig. 1 is the departure process schematic diagram of tension leg platform (TLP) upper chunk.

Detailed description of the invention

Below in conjunction with drawings and Examples, the present invention is described in detail.

Definition coordinate system: OXYZ is global coordinate system, and O point is positioned at center of gravity when platform is in equipoise, and OXY is parallel with standing level.GX ' Y ' Z ' is with the TLP satellite coordinate system moved, and G is the center of gravity of TLP.At initial time, OXYZ and GX ' Y ' Z ' coincidence.

Step 1: take the peripheral portion 2 of tension leg platform (TLP) upper chunk 1, be separated into infinitesimal 3 along axis.

Step 2: be distributed according to the tangential velocity of typhoon 4 and radial velocity, obtains the tangential wind speed of typhoon 4 suffered by infinitesimal 3 and radially wind speed.

Step 3: tangential wind speed and radial direction wind speed are decomposed global coordinate system (representing with subscript s in formula), obtains the wind speed in x-axis direction and the wind speed in y-axis direction.

Step 4: according to the movement velocity in tension leg platform (TLP) x and y-axis direction in global coordinate system and wind speed, obtain the relative velocity of tension leg platform (TLP) and typhoon 4:

Step 5: relative velocity is converted into the normal direction relative velocity vertical with axis:

Step 6: utilize world coordinates to be tied to the transition matrix C of satellite coordinate system, by normal direction relative velocityIt is transformed into satellite coordinate system from global coordinate system, obtains speed

$\stackrel{\→}{V}=C\·\stackrel{\→}{v}$

Step 7: count the wind load pointing to upper chunk 1 sidewall inter normal direction:

$\stackrel{\→}{f}=0.5\mathrm{\ρ}CA\stackrel{\→}{V}$

In formula, ρ is atmospheric density, and A is the area of infinitesimal sidewall.

Step 8: by transition matrix, by typhoon loadFrom satellite ordinate transform to global coordinate system:

$\stackrel{\→}{F}=C^{-1}\·\stackrel{\→}{f}$

Step 9: wind load suffered by each infinitesimal 3 is integrated, obtains wind load suffered by whole upper chunk 1.

Claims (1)

1. an ocean platform upper chunk typhoon load calculation method, comprises the following steps

Step 1: take the peripheral portion of tension leg platform (TLP) upper chunk, namely end to end cuboid, it is separated into structure infinitesimal along axis；

Step 2: be distributed according to the tangential velocity of typhoon and radial velocity, obtains the typhoon tangential velocity suffered by structure infinitesimal and radial direction wind speed；

Step 3: tangential wind speed and radial direction wind speed are decomposed global coordinate system, obtains x and the axial wind speed of y-coordinate；

Step 4: in conjunction with platform displacement speed, obtain the relative velocity of platform and typhoon；

Step 5: relative velocity is converted into the normal direction relative velocity vertical with axis；

Step 6: normal direction relative velocity is transformed into satellite coordinate system from global coordinate system；

Step 7: count the wind load pointing to upper chunk sidewall inter normal direction；

Step 8: by wind load from satellite ordinate transform to global coordinate system；

Step 9: wind load suffered by each infinitesimal is integrated, obtains wind load suffered by whole upper chunk.