1/3含口盖复合材料柱壳后屈曲性能

工程结构中复合材料柱壳已经得到了广泛使用,并且屈曲是其结构设计的一个主要问题。由于试验结果与线性屈曲理论分析结果的巨大偏差,线性特征值屈曲分析只能作为结构的一个初步评估方法,进一步分析可选用含初始几何缺陷的后屈曲分析。本文以轴压载荷下的1/3含口盖复合材料柱壳为研究对象,建立ABAQUS有限元模型,分别进行了基于Buckle算法的线性特征值屈曲分析、基于Riks法的含初始几何缺陷的非线性后屈曲分析,所得应变、载荷数值结果与试验结果吻合。非线性Riks后屈曲分析显示结构具有后屈曲承载能力和稳定的后屈曲平衡路径,能更准确地捕捉临界屈曲载荷,所得屈曲模态也更加贴近试验屈曲模态,因此,在设计上以含初始几何缺陷的Riks法得到的结果更加真实可靠。进行了含口盖复合材料柱壳的初始几何缺陷的敏感性分析,结果表明该结构对初始几何缺陷是非常敏感的,为了提高结构抗屈曲性能,应提高加工工艺质量,减少初始几何缺陷。

Post-buckling performance of 1/3 composite cylindrical shell with cover

Composite cylindrical shells are already commonly used in structural engineering,and their buckling is of vital importance in the design of such structures.The linear eigenvalue problem can be used as an initial analysis method due to the huge discrepancies observed between test results and theoretical predictions,and one can choose the geometrically nonlinear analysis for further study.The one-third composite cylindrical shells with cover were chosen as research object loaded in compression,and an ABAQUS finite element model was built at first.A linear eigenvalue analysis based on Buckle algorithm and a geometrically nonlinear post-buckling analysis based on Riks algorithm are developed for this research.The strain and load numerical results were matched well with test results.The Riks analysis shows that the structure has the postbuckling carrying capacity and can also reach a stable nonlinear equilibrium path,grasping the critical buckling load accurately,and the buckling modes are more close to the test ones.Therefore,it is more reliable to take the result based on geometrically nonlinear Riks algorithm as design criteria.A general geometrically imperfection sensitivity analysis is performed.The study shows that the cover shell is sensitive to imperfection,and we should improve the quality of processing and reduce the initial geometric imperfection in order to enhance stable performance.