相贯管切割角度计算分析

海洋钻井平台支撑结构均为管桁结构,依据焊接规范,管件的坡口角由相贯管件二面角确定,而多数相贯二面角沿其周向变化,导致实际装配时二面角无法测量;此外,由于相交管件偏心的存在,导致理论坡口角与实际切割角存在一定偏差,综上所述,相贯管件端口实际切割角度数据具有随二面角和偏心值变化的特点。利用空间几何向量及线性代数等数学知识建立相交管件的相贯线数学模型,导出了管件实际相贯线及切割角计算公式,利用MATLAB软件计算相贯管件端口切割角数据,通过将其作为相贯管件坡口角度的现场检测依据,用于检验数控切割指令正确性及切割设备的可靠性。以某钻井平台桩腿管件为例,对单重相交管件和简单二重相交管件的切割角度的进行了计算。算例显示,计算结果均在误差范围内(±5°),证明了切割指令的正确性及切割设备的可靠性。

Calculation and Analysis of Cutting Groove Angle of Intersecting Pipe

Support structures of the offshore drilling platforms are all pipe truss structure.In accordance with the welding conditions,the groove angle of intersecting pipe is determined by the dihedral angle of intersecting line,however,most intersecting dihedral angle changes along its circumferential direction,which results in the dihedral angle can not be measured in practical assembling of the pipes.In addition,the existence of intersecting pipe eccentricity leads to some error between theoretic values of groove angle and actual values of cutting angle.In summary,the actual cutting groove angle of the intersecting pipe end changes with the dihedral angle and eccentricity.Intersecting line mathematical model of the intersecting pipe is established,formulas of intersecting line and the cutting angle are derived by using mathematical knowledge of vector geometry and linear algebra.The data of actual cutting groove angle of the intersecting pipe end is calculated by MATLAB software,which can be used as basis of detecting the groove angle of the intersecting pipe in practical,in order to determine the correctness of CNC cutting and the reliability of cutting device.Taking leg pipe of certain drilling platform as example,cutting angle of the intersecting pipe is calculated.Calculating cases show that the results are all in the range of error（±5°）,which proves the correctness of CNC cutting and the reliability of cutting device.