Experimental Mechanics

, Volume 19, Issue 11, pp 389–398 | Cite as

Failure analysis of stainless steel at elevated temperatures

Stainless-steel rings subjected to internal pressure are tested to failure at 1100°F
  • C. A. Sciammarella
  • M. P. K. Rao
Article

Abstract

In this paper, particular emphasis has been put on gathering information on the phenomena that take place at the crack tip of a crack propagating at 1100°F. Since the experimental program was directed toward studying crack propagation in tubing, the tests were conducted on rings.

From the experimentally obtained data and from the correlation with the theoretically predicted values, the following picture emerges for the fracture behavior with full plasticity present. There is a region surrounding the crack tip where very large plastic deformations take place. This region is surrounded by a much larger region where the loading is nearly proportional and the behavior can be predicted well by the results of the deformation theory of plasticity and the theory of singularity fields. As the crack propagation initiates, there is a drastic change in the crack-tip configuration. The crack tip does not blunt and a fairly sharp crack-tip region is observed. The crack tip carries a large deformation field of a far more localized nature than that observed at the initiation of the crack growth.

Keywords

Stainless Steel Mechanical Engineer Plastic Deformation Elevated Temperature Fluid Dynamics 

List of Symbols

a

crack length

b

ligament length

length of miniature tensile specimen

n

strain-hardening coefficient

(r, θ)

polar coordinates

ro

notch-root radius

t

specimen thickness

(u, v)

displacement components

A

specimen cross-sectional area

A1,A2,C,C1,L

various constants

C.O.D.

crack-opening displacement

E

Young's modulus

In

function of the stress state

Jin

J-integral value for initiation of crack propagation

Jn

J-integral value characterizing singularity field

Kν,KE,KF,Ku,Kσ,K

scale of Poisson's ratio, elastic moduli, forces, displacement, stresses and length, respectively

P

load

δcr, δnocr, δtotal

displacement between two reference sections

\( \in _e \)

engineering strain at the notch-root (hoop strain)

\( \in _h \)

hoop strain

\( \in _{ij} \)

strain field

\( \in _p \)

effective plastic strain

\( \in _r \)

natural strain at the notch root

σ

hoop stress

σe

effective stress

σy

normal stress

Δ

arc length

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Copyright information

© Society for Experimental Mechanics, Inc. 1979

Authors and Affiliations

  • C. A. Sciammarella
    • 1
  • M. P. K. Rao
    • 2
  1. 1.Department of Mechanics and Mechanical and Aerospace EngineeringIllinois Institute of TechnologyChicago
  2. 2.Ford Motor Co.Detroit

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