Accession Number : ADA305245

Title :   Stress-Concentration Factors for Finite Orthotropic Laminates with a Pin-Loaded Hole.

Descriptive Note : Technical paper,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Crews, John H., Jr. ; Hong, C. S. ; Raju, I. S.

PDF Url : ADA305245

Report Date : MAY 1981

Pagination or Media Count : 44

Abstract : Stresses were calculated for finite-size orthotropic laminates loaded by a frictionless steel pin in a circular hole of the same diameter. These calculations were based on finite-element analyses for six laminates: quasi-isotropic 0 DEG/+45 DEG/90 DEGs, 0 deg, 90 deg, 0 DEG/90 DEGs, +/-45 DEGs, and 0 DEG/+/-45 DEGs. Stress concentration factors, based on nominal bearing stress, were determined for wide ranges of the ratios of width to diameter w/d and edge distance to diameter e/d. An infinite-laminate case was also analyzed for each laminate. Orthotropy had a significant influence on the tensile stress concentration at the hole. For example, the stress-concentration factors for the infinite-laminate cases ranged from 0.82 to 2.16, compared with 0.87 for the quasi-isotropic laminate. The finite widths and edge distances strongly influenced the tensile stress concentration. For the practical range w/d > 3 the peak tensile stresses were as much as 80 percent larger than the infinite-laminate reference value. For e/d > 3, these stresses were amplified by as much as 50 percent. In contrast, the finite width and edge distance had little effect on shear-out and bearing stress concentrations.

Descriptors :   *COMPUTATIONS, *LAMINATES, *PINS, *STRESS CONCENTRATION, STRESSES, PEAK VALUES, EDGES, FINITE ELEMENT ANALYSIS, TENSILE STRESS, HOLES(OPENINGS), WIDTH, RANGE(EXTREMES), RANGE(DISTANCE).

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE