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N. Levy

Bio: N. Levy is an academic researcher from Brown University. The author has contributed to research in topics: Crack closure & Crack growth resistance curve. The author has an hindex of 5, co-authored 5 publications receiving 843 citations.

Papers
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Journal ArticleDOI
James R. Rice1, N. Levy1
TL;DR: In this paper, an elastic plate with part-through surface crack, determining stress intensity factor for remote tensile and bending loads was used to calculate the stress intensity for bending loads.
Abstract: Elastic plate with part-through surface crack, determining stress intensity factor for remote tensile and bending loads

485 citations

Journal ArticleDOI
TL;DR: Elastic-plastic finite element analysis of near crack tip stress and strain field structure was performed in this article, where the authors used a finite element finite element (FME) model.
Abstract: Elastic-plastic finite element analysis of near crack tip stress and strain field structure

209 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized progress in the development of finite element methods for three-dimensional elastic-plastic stress analysis in fracture mechanics, focusing on the study of stress states near flaws such as a part-through crack in a pressure vessel wall.

62 citations

01 Jan 1969
TL;DR: In this paper, the authors proposed a method to estimate 2% of the users' confidence in the system's performance, which is the smallest percentage of the total number of users.
Abstract: Проведено дослідження литих загартованих стопів Ti–18Nb–хZr–1Si з вмістом цирконію від 2 до 8% ваг. Вивчався вплив Цирконію і температури гартування на структуру та твердість. Введення Цирконію має модифікуючий вплив на структуру литих стопів: із збільшенням його вмісту спостерігається зниження лікваційної неоднорідності та зменшення величини зерна. Показано, що у стопах Ti–18Nb–хZr–1Si (х = 2–8%) при гартуванні в залежності від температури витримки утворюється структура різної морфології та дисперсності. У стопі з низьким вмістом Цирконію ≤ 2% ваг. формується крупнопластинчаста α′′-фаза, близька до мартенситу в стопі Ti–18Nb–1Si, в той час як більший вміст Zr сприяє переходу до дисперсної тонкої пластинчастої чи голчастої форми мартенситу. За даними рентґенофазового та мікрорентґеноспектрального аналізу у стопах присутні силіциди (Ti, Zr)3Si та (Ti, Zr)5Si3, кількість яких також залежить від вмісту Цирконію і температури гартування. Максимальна твердість у стопах Ti–18Nb–хZr–1Si досягається при вмісті Zr ≅4–6% ваг. і температурах гартування 1100–1200°С.

56 citations

01 Apr 1968
TL;DR: In this article, the authors present calculations of the temperature elevations accompanying rapid plastic deformation near a crack tip, and show that the localized tip temperature elevation alone alone governs fracture toughness at very fast rates.
Abstract: : This paper presents calculations of the temperature elevations accompanying rapid plastic deformation near a crack tip. Solutions for the stress and strain distribution in non-hardening materials are employed as a basis for the heating rate distribution. Results are approximate in that temperature independent mechanical and thermal properties are assumed and thermal stressing is neglected. Two cases are considered: a stationary crack under increasing load, and a running crack with locally constant speed and plastic zone size. Numerical results are presented as based on properties of 2024 aluminum alloy, 6Al-4V titanium alloy, and mild steel. Temperature rises predicted for test conditions on these metals seldom exceed 100C. This may, nevertheless, be large enough to influence fracture and to account for the observed rise in roughness at very fast rates. Consequences are examined for the assumption that the localized tip temperature elevation alone governs fracture toughness at very fast rates. (Author)

55 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the critical value of tensile stress (a) for unstable cleavage fracture to the fracture toughness (K,,) for a high-nitrogen mild steel under plane strain conditions.
Abstract: SUMMARY AN ANALYSIS is presented which relates the critical value of tensile stress (a,) for unstable cleavage fracture to the fracture toughness (K,,) for a high-nitrogen mild steel under plane strain conditions. The correlation is based on (i) the model for cleavage cracking developed by E. Smith and (ii) accurate plastic*lastic solutions for the stress distributions ahead of a sharp crack derived by J. R. Rice and co-workers. Unstable fracture is found to be consistent with the attainment of a stress intensification close to the tip such that the maximum principal stress a,, exceeds a, over a characteristic distance, determined as twice the grain size. The model is seen to predict the experimentally determined variation of K,, with temperature over the range -150 to -75°C from a knowledge of the yield stress and hardening properties. It is further shown that the onset of fibrous fracture ahead of the tip can be deduced from the position of the maximum achievable stress intensiiication. The relationship between the model for fracture ahead of a sharp crack, and that ahead of a rounded notch, is discussed in detail.

1,374 citations

Journal ArticleDOI
TL;DR: In this paper, a crack in a structural member introduces a local flexibility that affects its vibration response, and the crack will open and close in time depending on the rotation and vibration amplitude.

1,080 citations

Journal ArticleDOI
James R. Rice1
TL;DR: In this paper, it was shown that if the displacement field and stress intensity factor are known as functions of crack length for any symmetrical load system acting on a linear elastic body in plane strain, then the stress intensity factors for any other symmetric load system whatsoever on the same body may be directly determined.

923 citations

Journal ArticleDOI
D. M. Parks1
TL;DR: In this article, a finite element technique for determination of elastic crack tip stress intensity factors is presented, based on the energy release rate, and the solution for only a single crack length is required, where the crack is 'advanced' by moving nodal points rather than by removing nodal tractions at the crack tip and performing a second analysis.
Abstract: A finite element technique for determination of elastic crack tip stress intensity factors is presented. The method, based on the energy release rate, requires no special crack tip elements. Further, the solution for only a single crack length is required, and the crack is 'advanced' by moving nodal points rather than by removing nodal tractions at the crack tip and performing a second analysis. The promising straightforward extension of the method to general three-dimensional crack configurations is presented and contrasted with the practical impossibility of conventional energy methods.

736 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented the stress-intensity factors for shallow and deep semi-elliptical surface cracks in plates subjected to tension and verified the accuracy of the three-dimensional finite-element models employed.

591 citations