钢结构重防腐涂层拉伸性能及本构研究

Study on Tensile Properties and Constitutive Relation of Heavy-duty Anticorrosive Coatings for Steel Structures

为研究钢结构重防腐涂层的拉伸性能和本构关系,以长效型底漆、中间漆、面漆及复合涂层为实验对象进行了单轴拉伸试验。通过对应力-应变曲线的阶段划分与实验数据拟合建立了涂层的本构表达式。基于实验结果确定了力学性能参数,结合混合物定律提出了用单一涂层预测复合涂层拉伸性能的表达式,并结合不确定度分析验证了理论预测的可靠性。研究表明:钢结构重防腐涂层为典型的塑性材料,涂层工作过程分为近似弹性、塑性强化、破坏3个阶段,本构关系可用线性函数与二次函数结合的分段函数表达。中间漆和底漆的弹性模量分别为面漆的54.11倍和7.22倍,为复合涂层的主要载荷承载部分,复合涂层的弹性模量和拉伸强度可由单一涂层加权预测且具有较高精度。

In order to study the tensile properties and constitutive relationship of heavy-duty anticorrosive coating for steel structures,the uniaxial tensile test was carried out with long-lasting primer,intermediate paint,topcoat and composite coating as experimental objects.The constitutive expression of the coating was established by fitting the stress-strain curves in phases with the experimental data.Based on the experimental results,the mechanical performance parameters were determined.According to the rule of mixture,an expression was proposed to predict the tensile properties of composite coating by single coating,and uncertainty analysis was used to verify the reliability of the theoretical prediction.The results showed that heavy-duty anticorrosive coating for steel structures was typical plastic materials,the working process of the coating was divided into three stages:approximate elasticity,plastic strengthening and destruction.The constitutive relation could be expressed in terms of a segmented function combining a linear function with a quadratic function.The elastic modulus of the intermediate paint and primer was 54.11 and 7.22 times that of the topcoat,respectively,which was the main load-bearing part of the composite coating.The elastic modulus and tensile strength of the composite coating could be predicted by single coating with high accuracy.