The Paton Welding Journal, 2012, №12



2012 №12 (09)

2012 №12 (02)

---

The Paton Welding Journal, 2012, #12, 2-8 pages  

CONSIDERATION OF PORE FORMATION AT ESTIMATION OF LIMITING STATE IN ZONE OF PRESSURE VESSEL WALL THINNING DEFECT

V.I. Makhnenko, E.A. Velikoivanenko, G.F. Rozynka and N.I. Pivtorak

E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
 
 
Abstract
The tough fracture models allowing for pores forming in plastic flow either at non-metallic inclusions or in matrix from the microcracks that do not propagate by cleavage mechanism provide for the corresponding algorithms of growth of the pore due to plastic strains and respective redistribution of the stress-strain state. At present, the interest in these models is determined by growth of the scope of prediction and expert estimates for the welded structures, based on calculation estimation of the limiting state. In a number of cases, in view of the trend to utilization of high-strength and sufficiently ductile materials in the welded structures, the limiting state occurs under the tough deformation conditions at the rigid stressed state, which contribute to the pore formation. Fracture as a result takes place at relatively small plastic strains that rapidly reduce deformation capacity of corresponding welded assemblies before fracture.
 
 
Keywords: steel pressure vessels, development of plastic flow, limiting state, pore formation, fracture zone, criteria of fracture involving pores, spontaneous fracture
 
 
Received:                ??.??.??
Published:               28.12.12
 
 
References
 
1. Romanova, V.A. (2008) Modeling of deformation and fracture processes in three-dimensional structurally heterogeneous materials: Syn. of Thesis for Dr. of Techn. Sci. Degree. Tomsk.
2. Karzov, G.P., Margolin, B.Z., Shvetsova, V.A. (1993) Physical-mechanical modeling of fracture processes. St.-Petersburg: Politekhnika.
3. Rybin, V.V. (1986) High plastic strains and fracture of metals. Moscow: Metallurgiya.
4. (1986) Static strength and fracture mechanics of steels. Ed. by V. Dal, V. Antonov. Moscow: Metallurgizdat.
5. Makhnenko, V.I. (1976) Computational methods for investigation of kinetics of welding stresses and strains. Kiev: Naukova Dumka.
6. Makhnenko, V.I., Velikoivanenko, O.A., Pozynka, G.P. et al. (2009) Stressed state in zone of thinning defects of thin-wall pipes. In: Problems of service life and service safety of structures, buildings and machines. Ed. by B.E. Paton. Kyiv: PWI.
7. (2000) Fitness-for-service: American Petroleum Institute recommended practice 579. 1st ed.

---

Suggested Citation

V.I. Makhnenko, E.A. Velikoivanenko, G.F. Rozynka and N.I. Pivtorak (2012) CONSIDERATION OF PORE FORMATION AT ESTIMATION OF LIMITING STATE IN ZONE OF PRESSURE VESSEL WALL THINNING DEFECT. The Paton Welding J., 12, 2-8.

---