湿热老化对FRP-钢胶接节点力学性能的影响

Mechanical behavior of FRP-steel adhesively-bonded joints under hygrothermal ageing

为进一步研究湿热老化对纤维增强复合材料(FRP)-钢胶接节点力学性能的影响,在现有试验的基础上,采用轮盘加载装置,分别从6个加载条件对湿热老化处理后的FRP-钢胶接节点进行一系列加载测试,研究了湿热老化对FRP-钢胶接节点的极限破坏荷载、破坏模式、刚度以及强度破坏准则的影响,并将结果与未老化胶接节点进行比较。试验结果表明:在剪切和拉伸荷载作用下,湿热老化显著降低了FRP-钢胶接节点的极限破坏荷载,分别降至11.0 kN和41.9 kN;在组合荷载作用下,湿热老化对极限破坏荷载的影响较小;老化与未老化FRP-钢胶接节点的强度破坏准则曲线彼此接近;对于拉伸和拉伸/剪切组合荷载条件,湿热老化改变了FRP-钢胶接节点的破坏模式,即从FRP夹芯板和结构胶粘贴层之间的部分界面破坏到覆盖整个结构胶粘结区域的FRP分层破坏和纤维断裂破坏的组合;在6个加载条件下,湿热老化均明显降低了FRP-钢胶接节点的刚度。因此,在设计及使用FRP-钢胶接节点时,应该充分考虑湿热老化对FRP-钢胶接节点力学性能的影响,避免其发生结构破坏。

In order to further investigate the effects of hygrothermal ageing on the mechanical behavior of fiber reinforced polymer(FRP)-steel adhesively-bonded joints,based on existing studies,a series of loading tests were carried out on the hygrothermal ageing-treated FRP-steel adhesively-bonded joints by using a roulette wheel loading device,respectively,from six loading conditions,to study the effects of hygrothermal ageing on the ultimate failure loads,failure modes,stiffness and strength failure criteria of the FRP-steel adhesively-bonded joints,comparing results with the unaged adhesively-bonded joints.The results show that hygrothermal ageing significantly reduces the ultimate failure loads of the FRP-steel adhesively-bonded joints to 11.0 kN and 41.9 kN under shear and tensile loading,respectively.Under combined loading,the effect of hygrothermal aging on the ultimate failure loads was less pronounced.The strength failure criteria curves of the aged and unaged FRP-steel adhesively-bonded joints are close to each other.For tensile and tensile/shear combined loading conditions,hygrothermal aging altered the failure modes of FRP-steel adhesively-bonded joints,transitioning from partial interfacial failure between the FRP core plate and the structural adhesive layer to a combination of FRP delamination failure covering the entire structural adhesive bonding area and fiber fracture failure.Hygrothermal ageing significantly reduced the stiffness of the FRP-steel adhesively-bonded joints under all six loading conditions.Therefore,the effects of hygrothermal ageing on the mechanical behavior of FRP-steel adhesively-bonded joints should be fully considered when designing and using FRP-steel adhesively-bonded joints to avoid their structural damage.