Multilayer hybrid-stress finite element analysis of a patched crack

✍ Scribed by Chen Wen-Hwa; Yang Shau-Hwa

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 963 KB
• Volume: 49
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(94)90048-5

✦ Synopsis

An assumed hybrid-stress finite element model together with two types of composite multilayer elements (MLTUP and MLTPH) is developed to study the crack patching problem. Three-dimensional mterlaminar stresses including transverse normal and shear stresses are accounted for. The assumed stress field satisfies: (1) the equilibrium conditions within each layer, (2) the interlaminar traction reciprocity condition at interlaminar boundaries and (3) traction-free boundary conditions on the top and bottom surfaces of the laminate.

Since the stress parameters assumed and the number of nodes taken are independent of the number of layers, the multilayer elements devised are applicable to the laminate with a large number of layers. The singly and doubly patched cracked panels under uniaxial tension are studied. At the same time, with a bending field induced, the strength can be predicted accurately without using the bending correction factors. In addition, the maximum stress intensity factor is found at the unpatched free surface, and an unbalanced composite patch is devised to extend the safe life of the cracked panel. Excellent agreemenets between the present results and referenced solutions show the high accuracy and validity of the present technique.