Abstract

DEFORMATION FIELD NEAR FATIGUE CRACK TIP OF STRUCTURAL MATERIAL SUBJECTED TO THERMAL LOADING

Onwubuya, M. N., Todo, C. & Obisue, E. I.

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Abstract This paper considers the deformation field near a crack tip due to thermal loading where crack tip singularities are examined using line integral which exhibits path independence of all contours near the tip of the crack in a two dimensional deformation field of an elastic material. The J- Integral is used to represents the magnitude of crack tip stress intensity factor under thermal stress crack problem; the characteristics of the J-integral in the presence of thermal stress are determined and a process of accessing the crack tip stress intensity factors is developed to understand line integral over a path enclosing the crack tip and an area integral enclosed by the path. The stress intensity factor solution for thermal stress and crack surface loading problem was also examined. The limiting value k* using the quarter point element displacement function is lower than the solution for this problem , and the maximum difference between the known solution and stress intensity calculated over the five path is discovered to be slightly greater . The values of k* calculated from the crack tip element is approximately 14 percent less than the average obtained using J- integral approach. The stress intensity factor calculated from the J ?integral calculation, over the five paths differed in not more than two percent from the average values and the extrapolation of the k* values from the crack tip back to will lead to a better agreement with the values obtained from J - integral stress intensity calculation. Keywords: Deformation Field, Fracture, j- integral, stress intensity factor and thermal loading

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