American Society of Civil Engineers

Stress Concentrations Near Holes in Laminates

by Richard M. Barker, M.ASCE, (Prof. of Civ. Engrg., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA), Jon R. Dana, (Grad. Student, Engrg. Sci. and Mech. Dept., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA), and Charles W. Pryor, Jr., A.M.ASCE, (Sr. Engr., Babcock and Wilcox, Power Generating Div., Lynchburg, VA)

Journal of the Engineering Mechanics Division
, Vol. 100, No. 3, May/June 1974, pp. 477-488

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Document type: Journal Paper
Abstract: Stress concentration factors are determined using a three-dimensional finite-element analysis for laminated composites pierced by circular, square, and diamond-shaped holes. Both angle-ply and bidirectional laminates are investigated for hole size to width-of-strip ratios from 0.125 to 0.417. Normal stress concentrations are found to be the least for square holes and greatest for diamond-shaped holes. Interlaminar shear stress concentrations, which cannot be determined by a two-dimensional analysis, are as large at the hole surface as those at the free edge when angle-ply laminates are utilized and the holes are large. For small circular holes, angle-ply (±45) laminates are recommended. When large holes are present, bidirectional (90/0) laminates are shown to be more efficient.

ASCE Subject Headings:
Composite materials
Material properties
Stress concentration