摘要
胶黏剂力学性能对碳纤维增强树脂复合材料(CFRP)加固钢结构的界面黏结性能影响显著。基于研制的胶黏剂配比,分析了不同纳米SiO2质量分数对胶黏剂常温固化后基本力学性能及微观结构的影响,制作了31个CFRP板-钢板双搭接试件,对其进行了常温固化后的承载能力、有效黏结长度、传力模式、黏结-滑移本构等试验研究,得出了纳米SiO2质量分数对CFRP板-钢板搭接试件界面黏结性能的影响规律,并与常用商品胶黏剂进行了比较。研究结果表明:随纳米SiO2质量分数的增加,胶黏剂应力-应变关系由线性转变为非线性,应变能、断裂伸长率及剪切强度分别最高提升了292.10%、202.88%和133.12%。微观结构分析表明纳米SiO2的添加使断面粗糙度显著增加,形成了密集的塑性空穴,产生了更多的微裂纹,使胶黏剂的韧性大幅度提高。当纳米SiO2质量分数从0增至1wt%,搭接试件破坏模式由界面破坏逐渐变为CFRP板层离破坏。掺入纳米SiO2能显著增加搭接试件的极限承载力(提升256.96%)及界面有效黏结长度(提升3倍),提高CFRP表面的应变及界面剪应力峰值。纳米SiO2质量分数为0与0.5wt%的搭接试件的黏结-滑移曲线为双线性三角形模型,纳米SiO2质量分数为1wt%的搭接试件的黏结-滑移曲线为三线性梯形模型,黏结界面韧性大幅提升。CFRP-钢界面承载能力受胶黏剂拉伸强度与断裂伸长率的双重影响,非线性高强度(即具有较高应变能)胶黏剂对应的CFRP-钢搭接接头具有更好的界面性能。
The mechanical performance of adhesives has significant effects on the interfacial bond behavior of the carbon fiber reinforced polymer(CFRP)-reinforced steel structures. Based on the developed ratio of adhesives,the effects of different nano-SiO2 on the basic mechanical properties and microstructure of the adhesives after curing at room temperature were analyzed. A total of 31 CFRP plate-steel double lap joint specimens were fabricated,and the experimental researches on bearing capacity, effective bonding length, force transmission mode, and bondslip constitutive after curing at room temperature were carried out. The influence of the amount of nano-SiO2 on the interfacial bonding properties of CFRP-steel lap joints was obtained and compared with commonly used adhesives.The results show that with the increase of nano-SiO2, the stress-strain relationship of the adhesive changes from linear to nonlinear, the strain energy, elongation at break and shear strength are increased by 292.10%, 202.88% and 133.12%, respectively. Microstructural analysis shows that the addition of nano-SiO2 significantly increases the section roughness forms dense plastic cavities, resulting in more microcracks, and greatly improves the toughness of the adhesive. When the amount of nano-SiO2 is from 0 to 1 wt%, the failure mode changes from interface failure to CFRP plate delamination. The incorporation of nano-SiO2 can increase the ultimate bearing capacity of the lap test piece(increase by 256.96%) and the effective bond length of the interface(up to 3 times), and improve the strain and interfacial shear stress peak of CFRP surface. The bond-slip curves could be simplified into a bilinear model(triangle-shape) for CFRP-steel joints with 0 and 0.5 wt% of the nano-SiO2, the bond-slip curve could be simplified into a trilinear model(trapezoidal-shape) of CFRP-steel joints with 1 wt% of nano-SiO2, and the bonding interface toughness is greatly improved. The bearing capacity of CFRP-steel interface is affected by the tensile strength and elongation at break of the adhesive. The CFRP-steel lap joint based on nonlinear high-strength adhesive(i.e. adhesive with higher strain energy) has excellent interface performance.
作者
李传习
李游
高有为
胡正
刘一鸣
LI Chuanxi;LI You;GAO Youwei;HU Zheng;LIU Yiming(Key Laboratory of Safety Control for Bridge Engineering of the Ministry of Education,Key Laboratory of Green Construction and Maintenance of Bridges and Buildings of Hu'nan Province,Changsha University of Science&Technology,Changsha 410114,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2020年第10期2619-2635,共17页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(51778069,51708047,51978081)
国家重点基础研究发展计划(973计划)项目(2015CB057701,2015CB057702)
广东省交通厅科技项目(201602010)
湖南省研究生科研创新重点项目(CX20190635)
桥梁工程安全控制教育部重点实验室开放基金项目(16BCX12)。
