Accession Number : ADP000012

Title :   Application of an Elastic-Plastic Methodology to Structural Integrity Evaluation,


Personal Author(s) : Ernst,H. A. ; Landes,J. D.

Report Date : SEP 1982

Pagination or Media Count : 23

Abstract : The elastic plastic fracture mechanics (EPFM) technology has advanced to the point where it can be used to make a realistic assessment of the structural integrity of components containing crack like defects. This evaluation is based on the ductile cracking character of the material as described in an R curve format where J (or a similar parameter) is plotted as a function of ductile crack extension, Delta a. The R curve is used along with the principles of tearing instability to predict the fracture behavior of the structure. This paper describes a methodology for incorporating the new concepts of EPFM into a structural stability evaluation. The structure is modeled as a cracked test specimen either in series or parallel with a spring. Both the deformation properties of this specimen as given by tensile test results and the crack growth properties as given by the R curve are combined to make the stability evaluation. The evaluation is straight forward when the model for the cracked structural component is nearly identical to the laboratory test specimen used to generate the material R curve.

Descriptors :   *Alloys, *Plastic deformation, *Modulus of elasticity, *Finite element analysis, Test and evaluation, Cracking(Fracturing), Defects(Materials), Ductility, Stability, Crack propagation, Fracture(Mechanics), Performance(Engineering), Reliability, J integrals, Stress strain relations, Displacement, Equations, Structural analysis

Subject Categories : Metallurgy and Metallography
      Numerical Mathematics
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE