Accession Number : ADA192296

Title :   Three-Dimensional Aspects of Fatigue Crack Closure.

Descriptive Note : Final rept.,

Corporate Author : PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS

Personal Author(s) : Grandt, A F ; Pope, J E ; Ray, S K

PDF Url : ADA192296

Report Date : Feb 1988

Pagination or Media Count : 205

Abstract : This final report summarizes progress on a basic research effort to determine three-dimensional aspects of the relationship between applied load and fatigue crack face separation. The research was motivated by the well known crack closure phenomenon, which indicates that naturally occurring fatigue cracks are physical held shut (or propped open) at zero load, so that crack surfaces do not separate in a linear elastic manner. Although prediction of fatigue crack opening behavior is of fundamental importance to many aspects of crack growth, relatively little is known about the three-dimensional character of closure. The research employed experimental and numerical procedures to develop predictive techniques for this important aspect of crack closure. Optical interference was used to measure crack opening in transparent polymer specimens, along with conventional crack opening and back face strain techniques for measuring crack closure. A numerical algorithm was developed to predict opening loads in surface flawed plates, and was compared with the experimental results. Keywords: Crack propagation, Cracking(Fracturing).

Descriptors :   *CRACKS, *POLYMETHYL METHACRYLATE, *POLYCARBONATES, ALGORITHMS, CRACK PROPAGATION, CRACKING(FRACTURING), ELASTIC PROPERTIES, FATIGUE(MECHANICS), INTERFERENCE, NUMERICAL METHODS AND PROCEDURES, OPTICAL PROPERTIES, POLYMERS, SURFACES

Subject Categories : Mechanics
      Plastics
      Polymer Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE