Abstract An experimental program was carried out on an axially loaded steel welded tubular T-joint made of circular hollow sections and strengthened with Glass/vinyl ester to study the effect of Glass Fiber Reinforced Polymer (GFRP) material on the Stress Concentration Factors (SCF) at both crown and saddle points on the chord member. Four tests were executed. The first test was performed on the plain joint which served as the reference for comparison, and the remaining three tests were performed on the strengthened joints with various FRP strengthening schemes. The arrangement of tests as well as specimen details together with most pertinent results are discussed. A significant drop in SCF values was observed for the FRP-strengthened T-joint as compared to the SCFs of the corresponding un-strengthened joint. The finite element model of the T-joint specimens were made and verified against the experimental data. Furthermore, extensive numerical analyses comprising of 1188 finite element models were performed to achieve a better understanding of the effect of the FRP parameters as well as the joint’s geometric parameters on the chord's SCFs. Additionally, through nonlinear regression analysis, SCF design equations were proposed for the fatigue design of axially loaded FRP strengthened tubular T-joints.

中文翻译：

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轴向载荷支撑下 FRP 加固管状 T 型接头中 SCF 的实验和参数研究

摘要 为了研究玻璃纤维增​​强聚合物 (GFRP) 材料对应力集中系数 (SCF) 的影响，在由圆形空心截面制成并用玻璃/乙烯基酯加强的轴向受力钢焊接管 T 型接头上进行了实验程序。在弦杆上的冠点和鞍点。进行了四次测试。第一个试验是在作为比较参考的平面接头上进行的，其余三个试验是在采用各种 FRP 加固方案的加强接头上进行的。讨论了测试的安排以及样本细节以及最相关的结果。与相应的未强化接头的 SCF 相比，FRP 强化 T 型接头的 SCF 值显着下降。制作了 T 型接头试样的有限元模型，并根据实验数据进行了验证。此外，还进行了包括 1188 个有限元模型的广泛数值分析，以更好地了解 FRP 参数以及接头几何参数对弦杆 SCF 的影响。此外，通过非线性回归分析，提出了用于轴向加载 FRP 加固管 T 型接头疲劳设计的 SCF 设计方程。