根据套管受到外挤载荷时的受力和变形特点,将套管变形分为弹性和塑性变形两个阶段,建立套管弹、塑性变形受力计算模型,利用能量平衡方程推导出套管抗挤强度计算公式,分析初始椭圆度、屈服强度和径厚比对套管抗挤强度的影响.通过对6根V140套管进行室内全尺寸试验和三维有限元数值模拟计算得到其抗挤毁强度,并与计算结果进行对比.结果表明:利用能量平衡方程推导的套管抗挤强度计算公式与试验、ISO/TR104002007(E)标准和有限元计算结果相比具有很高的精度,可以满足工程需求;初始椭圆度和径厚比越大,套管抗挤强度越小;屈服应力越大,套管抗挤强度越大.%The mechanics model was built up to calculate the collapse pressure of casing according to the force state and deformation behaviors of casing subjected to external pressure, based on energy balance method. The deformations of casing were divided into elastic and plastic deformations. The collapse pressure calculating equations of casing were deduced by the mechanics model. The influences of initial ovality, yield stress and diameter-thickness ratio on collapse pressure of casing were discussed. The collapse pressures of six V140 casings were tested and calculated by full-scale experiments and available method respectively to verify the calculating results. And also, the finite models (FM) were set up to simulate the casing subjected to external pressure. The comprehensive results indicate that the mechanics model agrees well with the experiment testing data, ISO/TR104002007 (E)code and FM results. The mechanics model is satisfied with the engineering demands.The elastic and plastic collapse pressures of casing decrease with the initial ovality and diameter-thickness ratio increasing.The collapse pressures of casing increase with the yield stress increasing.
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