风沙冲蚀下钢结构涂层的界面应力与破坏准则

为表征和评价风沙冲蚀作用下钢结构涂层界面结合强度,以西北地区风沙流特征为背景,利用接触力学和界面力学理论建立了在风沙冲蚀作用下钢结构涂层的界面应力表达式.结合断裂力学理论和有限元分析方法,确定了钢结构涂层的界面起裂位置.在起裂位置处建立了考虑压应力影响的界面应力破坏准则.研究结果表明：当冲蚀角度为30°和60°时,最大界面剪应力分别位于冲蚀点前侧200 mm和180 mm处,最大界面压应力分别位于冲蚀点前侧100 mm和50 mm处,涂层界面的起裂位置为最大界面剪应力处.风沙冲蚀作用下涂层的界面应力破坏准则与莫尔-库伦强度准则相似,斜率的大小取决于沙粒的冲蚀角度,且当冲蚀角度为30°和60°时,斜率大小分别为-0.599和-0.467.

Interfacial Stress and Failure Criteria of Steel Structure Coatings Under Wind-Sand Erosion

In order to characterize and assess the interfacial bonding strength of steel structure coatings under wind-sand erosion, expressions for calculating interfacial stresses of the steel structure coating under wind-sand erosion are established using theories of contact mechanics and interface mechanics, based on the typical sandstorm background of Northwest China. The interface crack initiation position of steel structure coating is determined by combined use of the fracture mechanics theory and finite element analysis method. The interfacial stress failure criterion considering the influence of compressive stress is established at the crack position. The results show that when the erosion angle is 30° and 60°, the maximum interfacial shear stress is located at 200 mm and 180 mm in front of the erosion point, and the maximum interfacial compressive stress is located at 100 mm and 50 mm in front of the erosion point, respectively. The interface crack in the coating initiates at the position of the maximum interfacial shear stress. In addition, the proposed interfacial stress failure criterion for coatings under wind-sand erosion is similar to the Mohr-Coulomb strength criterion. The slope depends on the erosion angle of the sand particles. When the erosion angle is 30° and 60°, the slope magnitude is ?0.599 and ?0.467, respectively.