摘要
为研究缝合密度、缝线纤维束规格以及钛合金板上预制的缝合孔直径对经过缝合的三维机织复合材料/钛合金混杂板缝合连接结构抗剪切能力的影响,对7组缝合参数各不相同的单搭接实验件进行剪切实验。通过加载条件下的原位细观实验观察,获得不同缝合参数下接头的失效模式,给出对应载荷-位移曲线上特征点的损伤形貌。结果表明:增加碳纤维缝线的丝束规格以及增加缝合密度均能提高混杂接头的失效载荷,且增加缝合密度比增加碳纤维缝线的丝束规格对提高失效载荷的效果更明显;缝合孔直径为2 mm或4 mm对结构承载能力无明显影响,当缝合孔直径达到6 mm时,承载能力明显降低;通过细观原位力学实验观察了三维机织复合材料/钛合金混杂板缝合结构剪切破坏过程;实验结果表明,搭接区的失效模式有缝线纯剪断、缝线抽出与剪断混合以及缝线挤出/剪断混合3种。缝合密度的变化是接头失效模式改变的主要因素。
In order to study the effect of stitching density,tow size of the suture and diameter of the stitching hole on the shear property of the stitched three-dimensional woven composite/titanium hybrid board stitching connection structure,seven groups of samples with different stitching densities,tow size of the suture and diameter of the stitching hole were tested.A reference group whose samples were unstitched was also tested to show the effect of stitching on the joint.Different failure modes of the lap zone with different stitching parameters were observed in in-situ meso-experiment,and the damage morphologies of the characteristic points on the load-displacement curve were given.The result shows that increasing tow size of the suture and increasing stitching density can both increase the failure load of the hybrid joint.Increasing the stitching density is proved more effective in improving the failure load.Doubling the stitching density can increase the failure load of the stitched joint about 82.0%.Doubling the tow size of the suture can only increase the failure load of the joint about 24.3%;Whether the diameter of the stitching hole is 2 mm or 4 mm do not influence the bearing capacity of the structure obviously,and when the stitching hole diameter reaches 6 mm,the bearing capacity is reduced due to the low strength of the epoxy resin in the gap between stitching hole and suture.It is dangerous to increase diameter of stitching hole above 4 mm;the shear failure of the stitched three-dimension woven composite/titanium alloy hybrid structure is observed by mesoscopic mechanical test.Composite/titanium alloy interface failure,crack initiation and extension in composite or in lap zone and failure of the lap zone are the three main stages of the structure failure observed in the test;The suture failure in the connect zone includes suture pull out and suture cut off.There are three failure modes of the lap zone observed in test.In suture cut off mode,all sutures in lap zone are cut off.The position at which the sutur
作者
卢轶榕
郑华勇
陈秀华
汪海
LU Yi-rong;ZHENG Hua-yong;CHEN Xiu-hua;WANG Hai(School of Aeronautics and Astronautics,Shanghai Jiao Tong University,Shanghai 200240,China;Aerospace System Engineering Shanghai,Shanghai 201109,China;Shanghai Key Laboratory of Spacecraft Mechanism,Shanghai 201108,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2020年第11期162-169,共8页
Journal of Materials Engineering
关键词
三维机织/钛合金混杂
缝合单搭接连接
剪切性能
原位实验
失效机理
three-dimension woven composite/Ti alloy hybrid
stitching single-lap connect
shear pro-perty
in-situ test
failure mechanism
