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Showing 1 to 20 of 33 for “"crack nucleation"”.
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Evaluation of susceptibility of AISI 304 to stress-corrosion cracking in terms of crack nucleation and crack propagation
… susceptibility of AISI 304 to stress-corrosion cracking in terms of time to crack nucleation and rate of crack propagation. U-bend specimens were exposed to magnesium chloride solutions boiling at atmospheric pressure for some predetermined time. The concentrations of magnesium chloride employed …
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Energy and Thermodynamically Based Approaches for Analysis of Damage in Contact Problems
… categories of contact damage are studied, namely crack nucleation and adhesive wear. The proposed methodology is primarily based on the laws of energy and thermodynamics, and as such offers great advantages by unifying the analysis of damage in a variety of contact configurations. Crack nucleation …
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Effect of pre-exposure thermal treatment on susceptibility of type 304 austenitic stainless steel to stress corrosion
… type 304 stainless steel to stress corrosion cracking was studied in terms of time for crack nucleation and rate of crack propagation. U-bend specimens were exposed to 42 weight percent magnesium chloride aqueous solution after pre-exposure heat treatments at 140°C and 154°C. The straight-line …
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Peridynamic analysis of fatigue crack growth in fillet welded joints
… classical methods to predict the crack propagation under cyclic loadings have some difficulties in treating complicated patterns of crack growth. A peridynamic theory, however, has powerful advantage on discontinuities. A peridynamic fatigue model, which is a bond damage model of …
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Stress and Damage Analyses of Thermal Barrier Coatings Under Cyclic Thermal Loading Conditions
… coat due to thermal mismatch stress via both crack nucleation and propagation and decohesion. In this thesis, this phenomenon was studied using a multi-physics approach...exceeding text limit
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Fatigue mechanisms in FV520B, a turbine blade steel.
… have been discussed. Using SEM, the fatigue crack nucleation mechanisms prevalent within the three microstructures in air and the chloride environment have also been identified. For the peak hardened material, nonmetallic inclusions dominated the fatigue crack nucleation process in air and …
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Theoretical analysis and experimental investigation of contact fatigue and surface damage in prealloyed and diffusion bonded sintered steels
… subjected to contact stress fail due to the nucleation of subsurface cracks (contact fatigue cracks), nucleation of brittle surface cracks, and surface plastic deformation. The occurrence of these contact damage mechanisms was predicted using theoretical models, which were developed by …
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Peridynamic modelling of localised corrosion damage
… the presence of field's discontinuities such as cracks and sharp concentration gradients. In order to overcome these limitations, a recently introduced continuum theory of mechanics based on integro-differential equations, peridynamics, is used for the first time for the modelling of …
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Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment
Some aspects of the corrosion fatigue crack initiation in EN1 type mild steel have been studied. Results of the electrochemical investigations show that the application of both static and compressive stresses enhance anodic dissolution. Application of cyclic stress assists the breakdown of the …
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Validation of a Computational Model for Predicting Fatigue Life
… does not use the Paris-Erdogan equation for crack growth. Two model parameters are the coefficients of the Ramberg-Osgood equation. The third model parameter is the total dissipation for the damage variable to reach a value of 1.0. Computer simulations of fatigue tests with block loading are …
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Deformation and fracture behavior during annealing of residually stressed polycrystalline aluminum oxide
… temperatures occurred by elastic creep through crack nucleation and growth in regions under tensile stresses. From the scanning electron fractographs, it was found that intergranular glassy phase played an important role in the crack formation and propagation. At elevated temperature, viscous …
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Reduction of friction in polymeric composites for artificial joint prostheses
… of the surface and subsurface layer which causes cracks to nucleate and propagate in the subsurface leading to the production of wear sheets. This research seeks a new alternative material to prevent the occurrence of delamination wear by the use of a fiber reinforced composite. The use of a …
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Quantitative phase-field modeling of crack propagation in multi-phase materials
… a computational framework for study of crack propagation in polycrystalline composite ceramics capable of designing micro-architectures of phases to improve fracture toughness and damage tolerance of ZrB<sub>2</sub>-based ultra-high temperature ceramics (UHTCs). A quantitative …
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Effects of water on chemomechanical instabilities in amorphous silica : nanoscale experiments and molecular simulation
… found that crystalline silica fails globally by crack nucleation, but amorphous silica displays plastic deformation due to the formation of local defects, which cascade into larger compound defects. We extend to amorphous systems the instability criterion for material failure and use the Lanczos …
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Roles of surface finish and hydrogen availability on the tensile properties of 1018 steel in hydrogen environments
… density increased. The strain-to-initiate cracking decreased with increased surface roughness. Elongation to fracture was shown to be a poor measure of hydrogen induced damage and crack nucleation was shown to be easier than crack propagation. Charging of specimens to at least 95% …
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Corrosion fatigue initiation in stainless steels : The scanning reference electrode technique.
… act as stress concentrators and promote fatigue crack nucleation. SRET measurements conducted during the potentiostatic generation of pits on the austenitic stainless steels in artificial seawater showed that the pit current density increases with the time of application of anodic polarisation. …
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Stress Corrosion Cracking of a Transformation Induced Plasticity Fe39Mn20CO20Cr15Si5Al1 High Entropy Alloy
Stress corrosion cracking (SCC) is a materials degradation phenomenon in which a susceptible material (metal) fails below its yield strength in a brittle manner because of the concomitant effect of a tensile load and a corrosive environment. After achieving a critical crack length, the component …
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Fatigue stiffness loss and life prediction technique development of a real rubber automotive component by means of Finite Element Analysis
… behaviour predictions. The work explores the nucleation and growth of cracks, but including stiffness loss and damage evolution. It has been performed in two filled rubbers, one natural rubber and one blend of StyreneButadiene (SBR) with polibutadiene (BR). Such techniques involve various …
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Crack path selection in microstructurally tailored inhomogeneous polymers
… that can help us experimentally study crack path selection problems. The model material which we are using is a polyethylene co-polymer, ECO, whose photosensitive behavior allows alterations in its mechanical properties when subjected to ultraviolet (UV) irradiation. It is seen that ECO …
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