An Automatic Micropolariscope Used to Study a Cracked Thread
A natural, three-dimensional, slightly curved crack was found in the thread of a frozen-stress model of a screwed tubular connection. The uncracked stress field in a similarly loaded cross-section was analysed using Frocht’s shear difference method. From slices containing the crack, the load transmitted locally, the extent of the region where linear elastic fracture mechanics should apply and non-dimensional stress intensity factors kII, kI, and f(rc o) were determined. Large variations in kII kI and f(rc o) were found in this non-uniform stress field.
KeywordsCrack Front Linear Elastic Fracture Mechanic Fringe Order Linear Fracture Mechanic Thread Profile
Unable to display preview. Download preview PDF.
- 1.Marston, R.E., “An automatic micropolariscope; its design, development and use for tubular joint stress analysis”, Ph.D. Thesis, Dept. of Mechanical Engineering, Nottingham University, 1985Google Scholar
- 2.Vickers, M17 Polarising Microscope, Vickers Ltd., York, England.Google Scholar
- 3.Paris, P.C. and Sih, G.C., “Stress Analysis of Cracks”, ASTM Spec. Tech. Pub. 381, 30-83, 1964.Google Scholar
- 4.Dally, J.W. and Sanford, R.J., “Classification of Stress-Intensity Factors from Isochromatic-Fringe Patterns”, Experimental Mechanics, 1978, 441–448.Google Scholar
- 5.Gdoutos, E.E. and Theocaris, P.S., “A Photoelastic Determination of Mixedmode Stress-Intensity Factors”, Experimental Mechanics, 1978, 87–96.Google Scholar
- 6.Frocht, M.M., “Photoelasticity”, Vol. 1, Ch. 2 and Ch. 8, John Wiley, NY, 1960.Google Scholar
- 7.Tesar, V., “La Photoelasticimetrie et ses Applications dans la Construction Aeronautique”, La Science Aerienne, 11, p.372–394, 1933.Google Scholar
- 8.Cartwright and Rooke, JSA, Vol. 10, No. 4, October 1975, pp. 217–224.Google Scholar