The Paton Welding Journal, 2000, №09

2000 №09 (13)

2000 №09 (15)

---

The Paton Welding Journal, 2000, #9, 87-91 pages

New approaches to assessing the welded joints life

V.V. Panasyuk, O.Ye. Andreykiv

G.V. Karpenko Physico-Mechanical Institute, XASU, Lviv, Ukraine

Abstract
The calculation model for solving the problems of welded joint life has been formulated. In the proposed model a welded joint is considered as a heterogeneous (by the physical and mechanical properties) deformed solid with a defect like faulty fusion-crack that propagates under cyclic loading of a body. The equations for estimating the fatigue crack growth rate were obtained on the basis of the balance of heterogeneous joint material fatigue fracture energy and reversive elastoplastic deformation of the process zone in the vicinity of the defect tip. The fatigue crack propagation direction with respect to initial defect plane was established from the condition that this direction provides the maximum crack rate. The proposed model was applied for assessing residual life of the butt and T-joints and a good correlation between the calculational and experimental data was found.
Keywords: welded joints, fatigue life, fatigue, crack, residual stresses, material inhomogeneity, fracture, energy criterion

References

1. Lepikhin, A.M., Moskvichyov, V.V. (1991) Characteristics of crack growth resistance of welded joints estimation, calculations and statistical analysis. Pacod. Laboratoria, 12,48-51.
2. (1993) The bases of structures design. Ed. by L.M. Lobanov. Kyiv: Kaukova Dumka.
3. Karzov, G.P., Leonov, V.P., Timofeyev, B.T. (1982) Welded high pressure vessels. Strength and life. Leningrad: Mashinostroyeniye.
4. Trufyakov, V.I. (1990) Strength of welded joints under alternating loading. Kyiv: Naukova Dumka.
5. Makhnenko, V.I., Pochinok, V.Ye. (1982) Application of fracture mechanics criteria to the strength calculations of welded joints with the discontinuities like cracks. Automaticheskaya. Svarka, 1, 1-6.
6. Andreykiv, O.Ye., Lishchynska, M.V. (1999) An equa tion of fatigue crack growth in heterogeneous plates. Fis.-khim. Meklianika Materialov, 3. 53 - 58.
7. Andreykiv, O.Ye., Lishchynska, M.V. (1999) Determination of the fatigue crack growth kinetics in butt welded joints. Masninoznavstoo, 2, 11 - 16.
8. Andreykiv, O.Ye., Lishchynska, M.V. (1999) Kinetic of fatigue crack growth and residual life of the welded joints. In: Fracture mechanics of materials and structural integrity. Lviv: Kamenyar.
9. Panasyuk, V.V., Andreykiv, O.Ye., Darchuk, O.I. et al. (1994) Analysis of short and long fatigue cracks growth kinetio. tinder non-regular loading, tn: Proc, of 10th. Europ. Conf. on Fracture.
10. Li, Y.C., Huang, N.C. (1991) Fatigue crack speed of materials with linear hardening. Int. J. Solids and struct., 7, 865 - 883.
11. Panasyuk, V.V., Andreykiv, O.Ye., Darchuk, O.I (1995) Calculation model of fatigue crack growth in elastic-plastic materials under mixed mode loading. In: Abstr. of Ith Int. Conf, on Mechanical Behaviour of Materials, Hague, Netherlands, May 28 - June 2, 1995. Hague.
12. Panasyuk, V.V., Andreykiv, O.Ye., Kovchyk, S.Ye. (1977) Methods of estimating the structural material crack growth resistance. Kyiv: Naukova Dumka.
13. Panasyuk, V.V. (1968) I.imit equilibrium of brittle bodies with cracks. Kyiv: Naukova Dumka.
14. Morrow, J. (1950) Investigation of plastic strain energy as a criterion for finite fatigue life. In: The Garret Corporation Report. Phaeniz Ariz.
15. Panasyuk, V.V., Andreykiv, O.Ye., Parton, V.Z. (1988) Fracture mechanics and strength of materials. In: Bases of fracture mechanics. Kyiv: Naukova Dumka.
16. (1979) Welding in mechanical engineering. Refer. Book. Moscow: Mashinostroyeniye.
17. Lishchynska, M. V. (1998) Estimation of stress intensify factors in the plates near curvilinear cracks. Fis.-khinl. Mekhanika Materialov, 1, 113 - 114.
18. Lishchynska, M.V. (1998) Propagation kinetics of piecewise-broken cracks in thin-walled elements subjected to long term static loading. In: Fracture mechanics and physics of building materials and structures. Lviv: Kamenyar.
19. Andreykiv, O.Ye., Darchuk, Л.I. (1992) Fatigue fracture and structural life. Kyiv: Naukova Dumka.
20. Makhnenko, V.I., Pochinok, V.Ye. (1984) Resistance to cyclic loading of the welded joints containing welds with incoriiplete faulty fusion. Aotomaticheskaya Svarka, 10, 33-40.

---

Suggested Citation

V.V. Panasyuk, O.Ye. Andreykiv (2000) New approaches to assessing the welded joints life. The Paton Welding J., 09, 87-91.

---