Buckling of Rectanglly Delaminate Composite Plates

• Main Authors: Yuh-Hwa Lin, 林玉華
• Other Authors: Shun-Fa Hwang
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/10338366537845717545

碩士 === 國立雲林科技大學 === 機械工程研究所 === 83 === Due to laminated structure , manufacturing defects or external impact , composite materials often contain delaminations . The buckling behavior of laminated plates with rectangle delamination under uniaxial compressive loading is studied here . Finite element methods are used to evaluate the buckling load , and to find out the corresponding buckling modes . Materials considered include short fiber composite materials and long fiber composite materials. For short fiber composite materials , the delaminated plate is modelled as a two dimensional problem by neglecting the effect of width. Two parameters , the size and the position along the thickness direction of the delaminated region , are varied to assess their influence on the buckling behavior of the plates . In order to overcome the singularity of the crack tip , the singular element is used around the crack tip to catch precise stress distribution . For the long fiber composite materials , is considered also the influence of angle-ply and cross-ply on the buckling behavior . Three parameters , including the size of the delaminated region , the position of the delaminated region in the thickness direction ,and the orientation of the fiber direction , are varied to evaluate the buckling load and the corresponding buckling modes . Uniform mesh refinement around the delaminated reigon edge is enforced to overcome the singul- arity of the crack tip . Whatever short fiber composite materials or long fiber composite materials , the results indicate that the buckling loads decrease as the delamination size increases , and the buckling modes change from a global type to a mixed type , then to a local type .If the position of the delamination is closer to the plate surface , the plates more easily buckle . Besides , for the long fiber composite materials , the buckling loads decrease as the orientation of the fiber direction increases , and the buckling modes do not change . The influence of plate width on the buckling behavior is not evident .