粘贴碳纤维复合材料后非承重十字形焊接接头疲劳性能  

Fatigue behavior of non-load carrying cruciform welded joints strengthened with carbon fiber sheets

作　　者：陈涛[1] 余倩倩[1] 顾祥林[1] 欧阳煜[2] 

机构地区：[1]同济大学建筑工程系,上海200092 [2]上海大学土木工程系,上海200072

出　　处：《建筑结构学报》2010年第S2期270-274,共5页Journal of Building Structures

基　　金：国家自然科学基金项目(50808139);上海市教育委员会和上海市教育发展基金会"晨光计划"项目(09CG16)

摘　　要：疲劳损伤是钢结构焊接节点失效的重要原因,现有的补强及止裂方法存在各自的缺点,而碳纤维复合材料在混凝土结构及砌体结构中的成功应用预示了其在钢结构中改善疲劳性能、延长结构物寿命的应用前景。选取非承重十字形焊接接头对碳纤维复合材料改善焊接接头的疲劳性能进行研究,考察外贴碳纤维复合材料用量和应力幅对疲劳寿命的影响。试验进行之前,采用硅基牙模材料等手段量测焊趾角度和半径。在试验进行中,观察试件破坏形态并记录相应的寿命。之后采用精细化模型,分析焊趾半径、复合纤维材料用量、粘贴材料弹性模量等参数对局部应力集中程度的影响。结果表明:碳纤维布加固能够提高疲劳寿命,参数分析表明焊趾半径对应力集中程度的影响最为显著。Fatigue damage is one of main failure modes for welded joints of steel structures.There are still some shortcomings for the existing strengthening or crack arrest methods for welded joints.Whereas,carbon fiber sheets,which have been successfully applied to the strengthening of concrete and masonry structures,may also be used to improve fatigue performance for welded joints.Several non-load carrying cruciform welded joints were tested with or without carbon fiber composite sheets to obtain their fatigue lives.Layers of sheets and stress variation range were considered in the test.Weld toe radius and flank angle were measured by using silicon based impression materials before test.Failure modes and corresponding fatigue lives were recorded during tests.Then,refined numerical models were adopted to perform numerical analysis.Various parameters,such as weld toe radius,layer of sheets and Young's modulus of strengthening materials,were considered to study their effects on local stress concentration.It was found that the fatigue life of a welded joint can be improved by carbon fiber composite sheets.And the results of parametric analysis showed that the weld toe radius is the controlling factor to influence the local stress concentration.

关 键 词：碳纤维复合材料 非承重十字形焊接接头 疲劳试验 有限元分析 焊趾半径 

分 类 号：TU391[建筑科学—结构工程]