Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 11 of 11 for “"Small scale yielding"”.
-
Fatigue Crack Closure and Crack Growth Outside the Small Scale Yielding Regime
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.
-
Closure of fatigue cracks at high strains
… was found to be less than for cracks under small scale yielding. For increased plastic deformations, the value of σ<sub>op</sub>/σ<sub>max</sub> is observed to decrease and approaches the value of R. Comparison of the experimental results with existing analysis has been made and indicates …
-
Numerical Analysis of Stable Crack Growth in Elastic-Plastic Materials in Small Scale and General Yielding
… used for steady state crack growth under small scale yielding conditions has the feature that the finite element mesh convects along with the moving crack tip. Various models for plastic flow were used. In Mode III, calculations were carried out for J(,2) incremental theory and a modified …
-
Constraint and Ductile Tearing Effects on the Cleavage Fracture of Ferritic Steel
… the ""local approach"" for fracture at the micro-scale. The E1921 procedures assume that uniform, small-scale yielding (SSY) conditions exist at fracture along the full crack-front. Plasticity induced constraint loss (crack-front triaxiality) frequently invalidates these assumptions. The …
-
Mechanisms of Ductile Fracture: Void Growth by Dislocation -Loop Emission and Hydrogen-Assisted Crack Propagation
… macroscopic crack propagation under plane strain small scale yielding conditions. Numerical results from crack growth simulations in the A533B pressure vessel steel indicate that hydrogen reduces both the initiation toughness and eliminates the tearing resistance of the material.
-
Steady crack growth through ductile metals: Computational studies
… damage break down numerically as vanishingly small load increments produce increasingly large amounts of crack extension. The computational model adopted here determines the deformation history of a steadily advancing crack directly without the need for a priori (transient) analysis that …
-
Aspects of the mechanics of metallic glasses
… metallic glass under Mode-I, plane strain, small-scale-yielding conditions. We show that our theory predicts important experimentally-observed, fracture-related phenomena in metallic glasses. " We have developed a large-deformation, elastic-viscoplastic constitutive theory in a temperature …
-
Numerical Modeling Issues in Finite Element Simulation of Plasticity Induced Crack Closure With an Emphasis on Material Model Effects
… (Lubliner's generalized plasticity)---into a 3D small scale yielding boundary layer approximation of a mode I crack. With the traditional method of growing the crack by one element per load cycle, the results display strong sensitivity to the element size. This work and the PICC literature …
-
Micromechanical Simulation of Fatigue in Nodular Cast Iron
… studied using a micromechanical cell model under small scale yielding conditions. The graphite particles are considered as voids, and they are resolved discretely in fracture process zone. The region outside of the fracture process zone is considered as a homogenized medium. When positive …
-
Hardening Cohesive/Overlapping Zone Model and Fractal Approach to Ductile Fracture
… and large crack extensions. In addition, even at small scale yielding, K, G, J- integral and COD are limitedly used to distinguish the onset of unstable fracture, without any concern regarding the pre-onset and post-reaction. On the other hands, the specimen size and geometry dependences of …
-
Spacetime damage-based cohesive model for elastodynamic fracture with dynamic contact
… accuracy and efficiency required to solve multiscale fracture problems. A dimensional analysis of linear elastodynamics, with extensions to fracture models based on cohesive traction--separation laws, supports the formulation. The problem is formulated and analyzed using differential forms and …