复合材料格栅圆柱筒稳定性数值仿真与试验

Numerical simulation and test on stability of composite grid stiffened cylinder

作为一种典型的航空航天结构,复合材料格栅圆柱筒的轴压稳定性决定了航天器结构的极限承载能力。现有的均匀化等效法和梁-壳有限元法模拟均存在一定的不足。考虑到肋条的局部应力和稳定性问题,将肋条等效为壳单元,提出了全壳有限元法。结合某型号飞行器复合材料格栅承力筒,分别采用这3种方法进行了轴压稳定性研究,同时设计了全尺寸轴压破坏试验。对比数值计算和试验结果得知两者的一致性较好,并且验证了该型号飞行器设计的合理性。均匀化等效法、梁-壳有限元法和全壳有限元法得到的结果与试验值的偏差分别为14.9%、9.5%和5.2%。全壳有限元法精度最高,并且能准确预测结构破坏位置,为同类结构的设计提供了参考。

As a typical aerospace structure,the axial compression stability of composite grid stiffened cylinder determines the ultimate bearing capacity of the spacecraft structure.The homogenization equivalent method and beamshell finite element method which have been researched are deficient.The local stress and stability of grids were taken into consideration,the grids were equivalent to shell elements,and the all-shell finite element method was put forward.Depending on the composite grid stiffened cylinder of certain aircraft,the three methods were used to study the axial compression stability respectively.Meanwhile,a full-size axial compression destruction test was also designed.Good agreement was achieved in the comparison between the numerical simulation and test results,which verified the rationality of the aircraft design.The deviation between the homogenization equivalent method,the beam-shell finite element method,the all-shell finite element method and test value are 14.9%,9.5%and 5.2%respectively.The all-shell finite element method has the highest precision,and can predict the failure modes accurately.The research can also be regarded as a design reference for similar structures.