Accession Number : ADA255431
Title : Kind-Band Failure Analysis of Thick Composites in Compression
Descriptive Note : Research and development rept.
Corporate Author : NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SHIP MATERIALS ENGINEERING DEPT
Personal Author(s) : Camponeschi, Jr , E T ; Gillespie, Jr , J W ; Wilkins, D J
Report Date : Apr 1992
Pagination or Media Count : 42
Abstract : This paper describes an analysis of 6.4 to 25.4 mm (0.25 to 1.0 in.) thick composite laminates subjected to uniaxial compressive loading that experimentally showed a decrease in strength with increasing thickness. The analysis was performed to determine if the reduction in strength was an intrinsic thickness material effect or if it could be attributed to through- thickness restraint on the specimen caused by the test fixture. The analysis was based on closed form solutions for the formation of kink-band failures in the presence of fibers misaligned with the principal axis of compression loading. The fiber misalignment was determined by a finite element analysis that accounted for the displacement of the laminate outer plies where the laminate exited the compression test fixture. The correlation between the experimental results and the theoretical analysis showed the compression strength of the AS4/3501-6 and S2/3501-6 laminates to be independent of thickness and directly proportional to the through-thickness fixture restraint on through-thickness Poisson expansion. This theoretical and experimental comparison also demonstrated a strong correlation between fiber misalignment, its resulting shear stress state and the kink-band compression failure mechanism. Composite Materials, Compression failure, Kink-Bands, Thick Composites.
Descriptors : *COMPRESSION , *THICKNESS , *LAMINATES , *FAILURE , *COMPOSITE MATERIALS , TEST AND EVALUATION , REDUCTION , SHEAR STRESSES , EXPANSION , TEST FIXTURES , MISALIGNMENT , RESTRAINT , CORRELATION , DISPLACEMENT , COMPARISON , FIBERS , FINITE ELEMENT ANALYSIS , MATERIALS
Subject Categories : Laminates and Composite Materials
Distribution Statement : APPROVED FOR PUBLIC RELEASE