复材长桁与钛合金接头超差对连接强度的影响

Impact Analysis of Connection Strength Between Composite Stringer and Titanium Alloy Joint With Out-of-Tolerance

针对复材长桁与钛合金接头因制造缺陷无法正常连接的情况,设计了正常连接、长桁立边失效连接、长桁自由边失效连接3种连接形式的对比试验,并采用有限元分析了超差连接情况下结构的破坏模式与破坏载荷的变化规律。结果表明:3种连接形式结构的破坏模式一致,均在蒙皮预制裂纹处沿着45°纤维方向破坏;不同连接形式对连接刚度基本没有影响;长桁立边失效对连接强度影响较小,破坏载荷下降5.31%;长桁自由边失效对连接强度影响较大,破坏载荷下降22.13%。长桁自由边失效是最严重的失效情况。

For the condition that composite stringer cannot connect the titanium joints properly due to the manufacturingdefect,three kinds of connecting type comparison tests are designed and the test conditions are normal connection,stringer vertical edge with failure and stringer free edge with failure,respectively.FEM is used to study the changes of the failure mode and failure load of the structure under the out-of-tolerance condition.The results show that the three connection type structures have the same failure mode which fails along the45°fiber of the skin precast crack;three different conditions almost have no influence on connection stiffness;the condition that stringer vertical edge with failure has less effect on connection strength,the failure loads decrease5.31%;the condition that stringer free edge with failure has greater effect on connection strength,the failure loads decrease22.13%.The condition that stringer free edge with failure is the most severe failure condition.