CFRP-钢界面粘结性能试验与数值模拟

碳纤维增强聚合物基复合材料（CFRP）与钢板的界面粘结性能为CFRP加固钢结构的关键问题之一。开展了17个CFRP板-钢板单搭接试件的拉伸剪切试验，研究了不同环氧粘结剂与CFRP材料的CFRP-钢界面力学行为和破坏模式；分析了粘结剂类型和CFRP材料对界面粘结滑移本构和界面剪切性能的影响，讨论了其承载力计算方法。结果表明：采用不同的粘结剂或CFRP材料，界面破坏形式和抗剪承载力均差异较大。采用Sika 330、Lica粘结剂的试件为CFRP板或钢板与胶层的界面破坏，采用Araldite粘结剂的试件为CFRP板浅表层离，采用Sika 30粘结剂的试件为胶层内聚破坏，采用SF（Sika S512/80）碳板的试件为CFRP板深层层离；Araldite试件的抗剪承载力为其他试件的1.7~2.9倍。Sika 330、Araldite及Lica试件粘结滑移曲线无明显下降段，属脆性破坏，而Sika 30与SF试件存在缓坡下降段，失效前有一定征兆；SF试件的粘结滑移本构可简化为三折线模型，其余试件则可简化为双线性模型。SF试件抗剪承载力需用Xia-a模型表征，其余试件则可用Xia-b模型表征。基于粘聚力模型对界面力学行为进行了数值模拟，结果表明，粘聚力模型可以较好地模拟界面的非线性力学行为，剥离应力对本单搭接试件的界面粘结强度影响很小。

Experimental study and numerical simulation for bond behavior of interface between CFRP and steel

The bond performance between carbon fiber reinforced polymer composites (CFRP) and steel plate is one of the key problems in strengthening steel structure with CFRP. Tensile-shear tests of 17 CFRP lamina-steel plate single-lap specimens were conducted, the mechanical behavior and failure modes of CFRP-steel interface of specimens with different epoxy adhesives and CFRP materials were studied. The influences of adhesive types and CFRP materials on interfacial bond-slip constitutive and shear bearing capacity were analyzed, and the calculation methods of interfacial shear capacity were discussed. Results show that interface failure modes and ultimate bearing capacity are significantly different for specimens with different adhesives or CFRP materials. The failure mode for specimens with Sika 330 and Lica adhesive is the mixed mode of CFRP-adhesive and steel-adhesive interface debonding, and failure modes for specimens with Araldite adhesive, Sika 30 adhesive, and SF (Sika S512/80) lamina are CFRP superficial delamination, adhesive failure, and CFRP deep layer delamination, respectively. The ultimate bearing capacity of Araldite specimen is 1.7~2.9 times of the other specimens. No descending branches are found in bond-slip curves for Sika 330, Araldite, and Lica specimens, which are characterized by brittle fracture of interfaces. However, low descending branches are found in bond-slip curves for Sika 30 and SF specimens, and forewarning signs occur before interfacial failure. The bond-slip constitutive model for the SF specimens can be simplified to trilinear model, while those for the other specimens can be simplified to bilinear models. The ultimate bearing capacity for SF specimens should be represented by Xia-a model, while those for the other specimens can be represented by Xia-b model. The mechanical behavior of the interface is numerically simulated based on cohesive zone model. Results show that the nonlinear mechanical behavior of the interface can be well simulated by the cohesive zone model, the influence of peeling stress on the bond strength of interface is small for these single-lap specimens.