局部减薄压力管道极限分析的弹性模量缩减法

发布时间：2018-05-05 07:14

  本文选题：局部减薄 + 压力管道　； 参考：《广西大学学报(自然科学版)》2017年01期

【摘要】：为求解含局部减薄缺陷水电站压力管道的极限承载力,提出了该类管道极限分析的弹性模量缩减法。该方法定义了表征单元接近塑性屈服程度的无量纲参数—单元承载比,提出了动态识别局部减薄管道高承载区域阈值基准承载比的计算方法,建立了相应的弹性模量调整策略,可通过基于塑性极限分析原理的线弹性迭代求解含局部减薄压力管道的极限荷载。算例分析表明:本文方法具有良好的计算精度和适用性;21组缺陷结构的计算结果与弹塑性增量法(EPIA)误差均在8%以内;局部减薄轴向长度、深度和周向长度对极限荷载影响依次降低,减薄轴向长度无量纲参数A/R0t超过2.4将可能使极限内压降低45%以上。本文方法可为含缺陷管道结构极限分析和安全评估提供参考。
[Abstract]:In order to solve the ultimate bearing capacity of pressure pipes of hydropower stations with local thinning defects, a reduction method of elastic modulus is proposed for the ultimate analysis of this kind of pipelines. In this method, the dimensionless parameter-element bearing ratio, which characterizes the element near the plastic yield degree, is defined, and the calculation method for dynamically identifying the threshold reference load ratio of the high bearing region of the local thinning pipeline is proposed, and the corresponding adjustment strategy of the elastic modulus is established. The linear elastic iteration based on the plastic limit analysis principle can be used to solve the limit load of the pipeline with local thinning pressure. Numerical examples show that the calculation results of 21 groups of defective structures with good calculation accuracy and applicability are within 8% of the error of Elastoplastic incremental method (EPI), and the axial length of local thinning is reduced. The influence of depth and circumferential length on the ultimate load decreases in turn, and the thinning of the axial length with dimensionless parameter A/R0t above 2. 4 may reduce the limit internal pressure by more than 45%. This method can be used as a reference for limit analysis and safety assessment of pipeline structures with defects.
【作者单位】： 广西大学土木建筑工程学院;广西大学工程防灾与结构安全教育部重点实验室;中国长江三峡集团公司乌东德工程建设部;
【基金】：国家自然科学基金资助项目(51469004) 广西高等学校高水平创新团队及卓越学者计划(桂教人[2013]38号)
【分类号】：TV732.4

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