Abstract
External circumferential strains were measured on large thick-wall pressure vessels containing internal fatigue cracks, using bonded strain gages. When strains measured over the cracks become compressive they predict impending failure. Normalization by the Lamé strain relates them to the fraction of fatigue life consumed and provides estimates of longevity.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- a :
-
crack depth
- a/2c :
-
aspect ration, crack depth to length
- a/(R 2 -R 1 ) :
-
ratio of crack depth to wall thickness
- D i :
-
inside diameter
- D o :
-
outside diameter
- L :
-
cylinder-specimen length
- N :
-
fatigue cycles
- N f :
-
cycles for failure
- P :
-
internal hydraulic pressure
- R :
-
radius to any point inside cylinder wall
- R a :
-
radius from center to crack tip
- R 1 :
-
inside radius
- R 2 :
-
outside radius
- t :
-
wall thickness
- x :
-
ratio of cycles at a given crack depth to the cycles for failure
- y :
-
ratio of measured strain in the crack plane to the theoretical Lamé strain on the outside of an uncreacked cylinder
- 2c :
-
longitudinal length of crack
- percent OS:
-
Percent overstrain
- ε:
-
measured circumferential strain
- \( \in _0 \) :
-
measured circumferential strain at crack plane
- \( \in _{th} \) :
-
theoretical Lamé strain at OD of uncracked cylinder
- \({{ \in _0 } \mathord{\left/ {\vphantom {{ \in _0 } { \in _{th} }}} \right. \kern-\nulldelimiterspace} { \in _{th} }}\) :
-
ratio of crack-plane strain to Lamé strain
- ϕ:
-
angle from crack plane
- σ:
-
circumferential stress
- σ I :
-
internal circumferential stress at crack tip
- σ o :
-
circumferential stress on outside surface
- σ y :
-
yield stress
- σ/P :
-
ratio of circumferential stress to pressure
References
Underwood, J.H., Lasselle, R.R., Scanlon, R.D. andHussain, M.A., “A Compliance K-Calibration For a Pressurized Thick-Walled Cylinder With a Radial Crack,”Eng. Fract. Mech.,4,231–244 (1972).
Shannon, R.W.E., “Crack Growth Monitoring by Strain Sensing,”Pres. Ves. & Piping, (1),61–73, Appl. Science Publ. Ltd., England (1973).
Throop, J.F. andFujczak, R.R., “Stress, Strain, and Deflection of Cracked C-shaped Specimens,”Experimental Mechanics,17 (8),290–296 (1977).
Throop, J.F., “Fatigue Crack Growth in Thick-Walled Cylinders,”Proc. Nat. Conf. on Fluid Power,XXVI,115–131,NCFP,Chicago (1972).
Davidson, T.E., Throop, J.F. andReiner, A.N., “The Role of Fracture Toughness and Residual Stresses in the Fatigue and Fracture Behavior of Large Thick-Walled Pressure Vessels,”Proc. Nat. Conf. on Fluid Power,XXVI,102–114,NCFP,Chicago (1972).
Timoshenko, S.P. andGoodier, J.N., Theory of Elasticity, 3rd ed., McGraw-Hill Book Company, New York, 68–71 (1970).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Throop, J.F., Fujczak, R.R. Strain behavior of pressurized cracked thick-walled cylinders. Experimental Mechanics 22, 277–286 (1982). https://doi.org/10.1007/BF02327245
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02327245