Abstract The pure mode-I, pure mode-II and the mixed-mode I/II fracture behavior of the adhesively-bonded pultruded GFRP/steel joint were experimentally investigated by using double cantilever beam (DCB) test, and four-point end-notched flexure (4ENF) test combined with four-point single leg bending (4SLB) test, respectively. The extended global method (EGM) was employed to obtain closed-form analytical solutions of mode-II fracture toughness for the 4ENF specimen and mixed-mode I/II fracture toughness components for the 4SLB specimen. Combined with the mode-I fracture toughness obtained by the experimental compliance method (ECM), the power law criteria in initiation and propagation processes were developed for adhesively-bonded pultruded GFRP/steel joint. Validation on the developed mixed-mode fracture criteria was performed through employing it to predict the load-displacement responses of the 4SLB specimens combined with VCCT. Finally, the mixed-mode fracture criteria of the adhesively-bonded GFRP/steel joint were compared to those of the adhesively-bonded GFRP/GFRP joint for quantifying their difference.

中文翻译：

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粘结拉挤GFRP/钢接头的混合模式I/II断裂标准

摘要 采用双悬臂梁 (DCB) 试验和四点端点试验，对拉挤拉挤 GFRP/钢接头的纯模态 I、纯模态 II 和混合模态 I/II 断裂行为进行了实验研究。缺口弯曲（4ENF）测试与四点单腿弯曲（4SLB）测试分别进行。采用扩展全局方法 (EGM) 获得 4ENF 试样的模式 II 断裂韧性和 4SLB 试样的混合模式 I/II 断裂韧性分量的闭合形式解析解。结合通过实验柔量法 (ECM) 获得的 I 型断裂韧度，为拉挤拉挤 GFRP/钢接头开发了起始和扩展过程中的幂律准则。通过使用它来预测 4SLB 试样结合 VCCT 的载荷位移响应，对开发的混合模式断裂标准进行了验证。最后，将胶粘 GFRP/钢接头的混合模式断裂标准与胶粘 GFRP/GFRP 接头的混合模式断裂标准进行比较，以量化它们的差异。