Stress concentration

About: Stress concentration is a research topic. Over the lifetime, 23250 publications have been published within this topic receiving 422911 citations.

Handbook of fatigue crack propagation in metallic structures

Abstract: Volume 1. Introductory Section. Failure criteria for anisotropic bodies (P.S. Theocaris). Introduction to fracture mechanics of fatigue (H. Kitagawa). Numerical methods for fracture parameters calculation (G.J. Tsamasphyros). Fatigue Behaviour of Metallic Materials. Fatigue of steels for concrete reinforcement and cables (M. Elices et al). Fatigue crack growth and crack shielding in a Fe-C-Cu sintered steel (Y-W. Mai et al). Fatigue and fracture properties of aerospace aluminium alloys (R.J.H. Wanhill). Fatigue crack propagation in titanium alloys (J.K. Gregory). Theoretical Models and Numerical Methods. Mechanical model for fatigue crack propagation in metals (X.-L. Zheng). Application of the three-dimensional boundary element method to quasistatic and fatigue crack propagation (M.H. Aliabadi, Y. Mi). Method of damage mechanics for prediction of structure member fatigue lives (X. Zhang et al.). Stochastic fatigue crack propagation (J.H. Yoon, Y.S. Yang). A fracture mechanics approach to the optimum design of cracked structures under cyclic loading (Z. Knesl). Fundamental Aspects of Fatigue Crack Propagation Phenomenon. Stable and unstable fatigue crack propagation in metals (V.T. Troshchenko). Fatigue crack growth from stress concentrations and fatigue life prediction in notched components (C.S. Shin). Propagation of surface cracks under cyclic loading (A. Carpinteri). Growth behaviour of small fatigue cracks and relating problems (H. Nisitani et al). Analytical and experimental study of crack closure behaviour (D.-h. Chen). Studies of fatigue crack closure (D. Francois). Fatigue threshold of metallic materials - a review (A. Hadrboletz et al). Mechanics of fatigue crack growth as a synthesis of micro-and macro-mechanics of fracture (V.V. Bolotin). Random material non-homogeneity effects on fatigue crack growth (K. Dolinski). Volume 2. Influence of Loading Conditions. Fatigue crack growth under variable amplitude loading (J. Dominguez). Mixed mode fatigue crack propagation (L.P. Pook). Numerical and. experimental study of mixed mode fatigue crack propagation (A.S. Kobayashi, M. Ramulu). Crack growth behaviour under repeated impact load conditions (T. Tanaka et al). Influence of Environmental Conditions. Influence of ambient atmosphere on fatigue crack growth behaviour of metals (J. Petit et al). Influence of hydrogen-containing environments on fatigue crack extension resistance of metals (V.V Panasyuk et al.). Fatigue crack propagation in aqueous environments (Y. Nakai). Application of fatigue crack growth data to low cycle fatigue at high temperature (L. Remy). Creep-fatigue interaction under high-temperature conditions (R. Ohtani, T. Kitamura). Fatigue crack propagation in metals at low temperatures (X.-L. Zheng, B.-T. Lu). (Part contents).

Toughening of Glasses by Metallic Particles

Abstract: The role of elastic, thermoelastic, and interfacial properties in the toughening of a brittle matrix by metallic second-phase particles was studied. Two composites were studied: glass+partly oxidized Ni particles (thermal expansion coefficient of the glasses lower than, equal to, and higher than that of Ni) and glass+partly oxidized Al particles (thermal expansion and elastic moduli equal). Weak interfacial bonding between the nickel and its oxide and developed stress concentrations are the major toughness limitations found in the glass/Ni composites. When the thermal expansion coefficient and elastic modulus of the second phase are sufficiently greater than that of the glass matrix, a propagating crack will bypass the particles. When the thermal and elastic stresses are minimized and satisfactory bonding is achieved (glass/Al composites), a 60x toughness increase was realized.

Transition from pitting to fatigue crack growth—modeling of corrosion fatigue crack nucleation in a 2024-T3 aluminum alloy

Abstract: The nucleation of fatigue cracks from corrosion pits was investigated by conducting fatigue experiments on open-hole specimens of a 2024-T3 aluminum (bare) alloy in 0.5 M NaCl solution at room temperature and different load frequencies from 0.1 to 20 Hz. The maximum cyclic stresses applied at the hole ranged from 144 to 288 MPa and the load ratio, R , was 0.1. A specimen subjected to pre-corrosion in the NaCl solution prior to corrosion fatigue was also investigated. Pitting was found to be associated with constituent particles in the hole and pit growth often involved coalescence of individual particle-nucleated pits. Fatigue cracks typically nucleated from one or two of the larger pits, and the size of the pit at which the fatigue crack nucleates is a function of stress level and load frequency. The observations indicate that the nucleation of corrosion fatigue cracks essentially results from a competition between the processes of pitting and crack growth. Pitting predominates in the early stage of the corrosion fatigue process, and is replaced by corrosion fatigue crack growth. Based on these results, two criteria are proposed to describe the transition from pit growth to fatigue crack growth: (1) the stress intensity factor of the equivalent surface crack has to reach the threshold stress intensity factor, Δ K th , for fatigue crack growth, assuming that a corrosion pit may be modeled by an equivalent semi-elliptical surface crack, and (2) the time-based corrosion fatigue crack growth rate also exceeds the pit growth rate.

Effect of SiC volume fraction and particle size on the fatigue resistance of a 2080 Al/SiCp composite

Abstract: The effect of SiC volume fraction and particle size on the fatigue behavior of 2080 Al was investigated. Matrix microstructure in the composite and the unreinforced alloy was held relatively constant by the introduction of a deformation stage prior to aging. It was found that increasing volume fraction and decreasing particle size resulted in an increase in fatigue resistance. Mechanisms responsible for this behavior are described in terms of load transfer from the matrix to the high stiffness reinforcement, increasing obstacles for dislocation motion in the form of S’ precipitates, and the decrease in strain localization with decreasing reinforcement interparticle spacing as a result of reduced particle size. Microplasticity was also observed in the composite, in the form of stress-strain hysteresis loops, and is related to stress concentrations at the poles of the reinforcement. Finally, intermetallic inclusions in the matrix acted as fatigue crack initiation sites. The effect of inclusion size and location on fatigue life of the composites is discussed.