利用TS-802高强度胶黏剂对高碳不锈钢进行对接胶接接头连接,对不同固化过程试样,分别采用单轴拉伸和四点弯曲实验,测试研究其对接胶接接头的内聚强度;通过隔离体平衡法和中性轴平移法分析了四点弯曲加载方式下界面应力的演化过程,并通过实验验证胶黏剂的层内缺陷对内聚强度的影响。研究表明,室温下固化24h与80℃固化2h相比,后者具有更高的内聚强度;在固化过程中,胶黏剂胶层内部不可避免产生缺陷,缺陷主要集中在中央区域,而在边缘区域为光滑无缺陷区,因此四点弯曲加载方式下界面具有更高的边缘应力内聚强度;隔离体平衡法和中性轴平移法两种理论分析均表明,常规弯曲应力公式与本文中推导得到的应力公式的理论比值为2.5.本文的实验和理论研究有助于更系统和更深入地理解胶黏剂的内聚强度受不同固化方式及不同强度测试手段的影响。
The commercial adhesive TS-802 with high cohesive strength was used to obtain different strengths of butt-jointed stainless steel under different curing conditions.Uniaxial tensile test and four-point bending test were performed to measure the cohesion strength of adhesive butt-joint.To elucidate the interface stress evolution under four-point bending mode,the theoretical analysis of free-body equilibrium method and neutral axis translation method were conducted.Experimental research was carried out to verify the influence of adhesives layer defects on cohesion strength.Results show that the cohesion strength of butt-joint cured at 80 ℃ for 2h was higher than that cured at room temperature for 24 h.The adhesive butt-joint inevitably produced defects during the curing process,which were randomly distributed in the middle zone of the adhesive.Thus,under the four-point bending loading the interface had higher edge stress cohesion strength.Theoretical analysis shows that the theoretical ratio was 2.5by comparing the conventional bending formula with the derived formula in this paper.This research is helpful to understand the adhesives cohesive strength influenced by both curing methods and stress loading modes.