Use of linear and nonlinear fracture mechanics for assessing resistance to crack propagation in 15Kh2NMFA structural steel

1978 ◽  
Vol 10 (1) ◽  
pp. 38-42
Author(s):  
A. Ya. Krasovskii ◽  
V. A. Vainshtok ◽  
Yu. A. Kashtalyan ◽  
V. A. Stepanenko ◽  
A. N. Vashchenko ◽  
...  
2005 ◽  
Vol 127 (2) ◽  
pp. 179-183 ◽  
Author(s):  
Igor Ye. Telitchev

The present paper summarizes the results obtained from impacts on shielded pressure vessels and analyzes the conditions under which bursting of a shielded pressure vessels occur that are damaged by space debris. The semianalytical model was generated to describe the processes occurring upon impact of a hypervelocity projectile into a shielded vessel. A model capable to describe the failure mechanisms of damaged vessels is suggested. Nonlinear fracture mechanics techniques were used to analyze and predict whether a vessel perforation will lead to mere leakage of gas, or whether unstable crack propagation will occur that leads to catastrophic fracture of the vessel. The validity of the developed model is tested by simulating the experimental results.


2013 ◽  
Vol 4 (4) ◽  
pp. 457-476 ◽  
Author(s):  
Yury Matvienko

Purpose – The purpose of this paper is to develop basic principles of deterministic structural integrity assessment of a component with a crack- or notch-like defect by including safety factors against fracture and plastic collapse in criteria equations of linear and nonlinear fracture mechanics. Design/methodology/approach – The safety factors against fracture are calculated by demanding that the applied critical stress should not be less than the yield stress of the material for a component with a crack or a notch of the acceptable size. Structural integrity assessment of the engineering components damaged by crack- or notch-like defects is discussed from view point of the failure assessment diagram (FAD). The methodology of the FAD has been employed for the structural integrity analysis and assessment of acceptable sizes of throw-thickness notch in a plate under tension and surface longitudinal notch-like defects in a pressure vessel. Findings – Basic equations have been presented to calculate the safety factor against fracture for critical values of the stress intensity factor, crack tip opening displacement (CTOD), the J-integral and the FAD as well as to estimate an acceptable (safe) region for an engineering component with a crack- or notch-like defect of the acceptable size. It was shown that safety factors against fracture depend on both the safety factor against plastic collapse and employed fracture mechanics criterion. The effect of crack/notch tip constraint is incorporated into criteria equations for the calculation of safety factors against fracture. Originality/value – The deterministic method of fracture mechanics is recommended for structural integrity assessment of a component with a crack- or notch-like defect by including safety factors against fracture and plastic collapse in criteria equations of linear and nonlinear fracture mechanics.


1987 ◽  
Vol 19 (4) ◽  
pp. 553-559 ◽  
Author(s):  
E. M. Morozov ◽  
G. P. Nikishkov ◽  
B. R. Beizerman ◽  
Yu. I. Smirnov ◽  
T. A. Chernysh ◽  
...  

2018 ◽  
Vol 84 (11) ◽  
pp. 46-51 ◽  
Author(s):  
N. A. Makhutov

The results of comprehensive studies of multifactor processes, mechanisms and criteria for fracture at a variation of the crack-like defect state, loading conditions and mechanical properties of structural materials carried out in the 20th - 21st centuries are presented on the basis of monographic publications and articles published in the journal “Zavodskaya Laboratoriya. Diagnostika Materialov.” Crack resistance of materials and structures has become a key problem of the material science, technology, design, manufacture and service of structures. Fracture mechanics including estimation of the stress-strain and limiting states in a cracks tip formed a scientific basis of the crack resistance analysis Stress intensity factors (linear fracture mechanics) and strain intensity factors (nonlinear fracture mechanics) are accepted as the basic criteria of those states. The basic computational relations for construction of the fracture diagrammes which link the cracks growth with conditions of a static, cyclic, long-term, dynamic loading are presented. Parameters of computational relations are put into correspondence with the features of fracture processes on nano-, micro-, meso- and macrolevels. Prospects of the research and guidelines of further studing crack resistance are discussed.


Impact ◽  
2019 ◽  
Vol 2019 (10) ◽  
pp. 105-107
Author(s):  
Hiroshi Okada

Professor Hiroshi Okada and his team from the Department of Mechanical Engineering, Faculty of Science and Technology, Tokyo University of Science, Japan, are engaged in the field of computational fracture mechanics. This is an area of computational engineering that refers to the creation of numerical methods to approximate the crack evolutions predicted by new classes of fracture mechanics models. For many years, it has been used to determine stress intensity factors and, more recently, has expanded into the simulation of crack nucleation and propagation. In their work, the researchers are proposing new methods for fracture mechanics analysis and solid mechanics analysis.


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