Accession Number:

AD0728277

Title:

Analytical Approach to Composite Behavior.

Descriptive Note:

Summary technical rept. 1 Mar 70-28 Feb 71,

Corporate Author:

CASE WESTERN RESERVE UNIV CLEVELAND OHIO DIV OF METALLURGY AND MATERIALS SCIENCE

Report Date:

1971-08-01

Pagination or Media Count:

153.0

Abstract:

Study in the areas of the effects of biaxial stress states on composite deformation the effect of a fiber-matrix diffusion layer on uniaxial composite properties and of non-cylindircal geometry effects on model predictions is reported, as well as continuation of efforts in fiber and effect and residual stress studies. Additional data were acquired on the bulging of composite sheets under balanced and unbalanced biaxial tension which supported the earlier observation of increased transverse yield and fracture strengths. A BIAXIAL YIELD CRITERION WAS DEVELOPED WHICH USED ACTUAL STRESS DISTRIBUTIONS WITHIN THE COMPOSITE UNDER BIAXIAL LOADS AS COMPUTED BY A FINITE ELEMENT TECHNIQUE TO PREDICT COMPOSITE YIELDING. This criterion gave better predictions than did a Hill Criterion. Fiber-matrix diffusion effects were studied in Ni-Cu cylindrical composites by subjecting composites, as well as component specimens to diffusion treatments prior to tensile testing. Experimental stress-strain behavior was compared to that predicted from the concentric cylinder analytical model with the modification that the properties of the diffusion products were included in interfacial rings. The effects of a solid solution diffusion layer on composite tensile properties was small. The macrogeometry effect on the stress- strain behavior of unidirectional composites was investigated using prototype copper- tungsten cylindrical square, and plate specimens. The uniaxial stress-strain behavior did not reveal the effect of geometry as was anticipated. Strain ratio data were too inconsistent to conclude whether a geometric effect existed for the variables investigated. Author-PL

Subject Categories:

  • Laminates and Composite Materials

Distribution Statement:

APPROVED FOR PUBLIC RELEASE