粘接技术作为传统的焊接、铆接、螺栓连接等技术的替代已经被广泛地应用于土木工程中。为减少粘接层的应力集中,采用端部为楔形的CFRP板及保留板端溢出的胶水为工程中常用的方法。通过有限元对一般板端、板端楔形、板端反楔形及板端溢胶等情况进行了界面应力分析。结果显示,由于梁与胶层界面端部奇异点的影响,胶层底部和顶部的最大界面应力有很大差别;而板端溢胶能降低奇异点处的剪应力和正应力集中,并且使得应力的分布更平缓,这也造成板端溢胶情况的裂缝开展不在奇异点,而在溢出胶的斜面;板端正、反楔形均能降低应力集中,而反楔形的效果要好于正楔形;板端溢胶降低正应力的效果要好于板端楔形,但板端反楔形对降低剪应力的效果则要好于板端溢胶。这些结论与搭接头研究的结果一致,但加固梁的最大界面应力减小幅度要远小于搭接头。
The adhesive bonding technique has been widely used in construction as an alternative of conventional joint techniques. Spew fillet and tapered plate are suggested to reduce the stress concentration in the adhesive layer of retrofitted beams. Finite element (FE) analysis was employed to determine the effects of the spew fillet and the taper on interracial adhesive stresses. The cases, including squared end, outside taper, inside taper and with fillet, have been considered. The results of the FE analysis show that the adhesive stresses in the upper and the lower interfaces are different due to the singularity at the adhesive corner. Both tapers and spew fillet can reduce the adhesive stresses. The spew fillet is better than tapers in reducing the normal stress, but the inside taper is more effective in reducing the shear stress than the fillet. The results also show that the results largely agree with the findings on lap joints, but the effect of spew fillets is far less than that for lap joints.