薄壁衬层再生复合管材层间界面力学行为分析

Analysis on the Mechanical Behavior of the Interlayer Interface of a Recycled Composite Pipe with a Thin-walled Lining

为研究薄壁衬层再生复合管材层间界面力学行为,对带腐蚀缺陷管钢与薄壁不锈钢衬层所组成的复合管材进行切向与法向拉伸破坏试验,基于试验结果,建立了带腐蚀缺陷管钢修复后的有限元分析模型。试验试件在切向力作用下的试验结果表明,随着带腐蚀缺陷管钢腐蚀程度的增加,粘结层与基层管钢剥离所占的比例逐渐减小,界面极限强度逐渐增大,界面黏聚力随着腐蚀损失率的增加略有增加,但随着粘结材料失效所占比例的增加,这种增加趋势慢慢趋于平缓,层间界面切向破坏以粘结材料内聚力失效为主。试验试件在法向力作用下的试验结果表明,各试件的破坏形式基本相同,破坏以粘结层内聚力失效破坏为主。利用差值法建立复合管材层间界面切向应力与相对位移双线性本构关系模型,界面法向应力与相对位移之间的关系也可简化为双线性本构关系。通过有限元分析模型对试件进行了数值分析,分析结果与试验结果基本吻合,双线性界面内聚力模型在有限元模型分析中能够准确模拟薄壁内衬复合管材层间力学性能,研究内容和结果可为埋地管道非开挖连续内衬修复技术提供理论依据。

In order to study the interlaminar mechanical behavior of regenerated composite pipes with thin-walled lining,tangential and normal tensile failure tests are carried out on the composite pipes with corroded defects and thin-walled stainless steel lining.Based on the test results,a finite element analysis model is established for the repaired pipes with corroded defects.The test results of test specimen under the effect of tangential force show that with the increase of pipe steel corrosion extent with corrosion defects,bonding layer and the base pipe steel strip gradually decreases,the ultimate strength of the interface between the layers increase gradually,and with the increase of the corrosion loss rates,the interface cohesive force has a slight increase.But with the increase of proportion of binding material failure,this increased trend gradually flatten out.The tangential failure of interlayer interface is mainly due to the failure of cohesive force of binder.The test results under normal force show that the failure modes of each specimen are basically the same,and the failure is mainly the failure of cohesive force of the bonding layer.A bilinear constitutive model of tangential stress and relative displacement at interlayer interface of composite pipes is established by difference method.The relation between normal stress and relative displacement at interlayer interface can also be simplified to bilinear constitutive relation.The finite element analysis model is used to analyze the specimen,and the analysis results are in good agreement with the test results.The bilinear interfacial cohesive force model can accurately simulate the interlaminar mechanical properties of thin-walled composite pipes in the finite element model analysis.The research content and results can provide a theoretical basis for the trenchless continuous lining repair technology of buried pipeline.