Abstract: This paper presents the static and fatigue tests of hybrid (bonded/bolted) glass fiber reinforced polymer (GFRP) joints. Nine specimens of single-lap hybrid GFRP joints have been fabricated to study the static and fatigue behaviors in the experimental campaign. The static tests of uniaxial tension loading are first conducted, from which the static ultimate bearing capacities of the joints are obtained. High-cycle fatigue tests are subsequently carried out so that the fatigue failure mode, fatigue life, and stiffness degradation of joints can be obtained. The measuring techniques including acoustic emission monitoring and three-dimensional digital image correlation have been employed in the tests to record the damage development process. The results revealed that the static strength and fatigue behavior of such thick hybrid GFRP joints were controlled by the bolted connections. The four stages of fatigue failure process are obtained from tests and acoustic emission signals analysis: cumulative damage of adhesive layer, damage of the adhesive layer, cumulative damage of GFRP plate, and damage of GFRP plate. The fatigue life and stiffness degradation can be improved by more bolts. The S-N (fatigue stress versus life) curves for the fatigue design of the single-lap hybrid GFRP joints under uniaxial tension loading are also proposed.

Key words: glass fiber reinforced polymer (GFRP) joint, hybrid bonded/bolted connection, fatigue behavior, acoustic emission, digital image correlation

摘要： 本文针对9个单搭接玻璃纤维复合材料（GFRP）胶栓混合节点试件，开展了静力和疲劳试验。首先通过单轴拉伸的静力试验，得到了节点的静力极限承载力，随后开展了高周疲劳试验，得到了节点的疲劳失效模式、疲劳寿命和刚度退化。在试验过程中采用了声发射监测和三维数字图像相关法等监测技术记录了节点损伤发展过程。试验结果显示，该类GFRP节点的静力和疲劳性能主要由螺栓连接控制。基于试验和声发射信号结果发现疲劳失效过程可以分为4个阶段：胶层的累积损伤，胶层的完全损伤，GFRP板的累积损伤和GFRP板的完全损伤。增加螺栓数量可以提高节点疲劳寿命，并减少刚度退化速率。本文还提出了单搭接GFRP混接节点在单轴拉伸载荷下的疲劳S-N设计曲线。

关键词: 玻璃纤维复合材料节点，胶栓混合节点，疲劳性能，声发射，三维数字图像相关法