다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Overview of constitutive laws, kinematics, homogenization and multiscale methods in crystal plasticity finite-element modeling: Theory, experiments, applications

1. Introduction and overview 2. Film stress and substrate curvature 3. Stress in anisotropic and patterned films 4. Delamination and fracture 5. Film buckling, bulging and peeling 6. Dislocation formation in epitaxial systems 7. Dislocation interactions and strain relaxation 8. Equilibrium and stability of surfaces 9. The role of stress in mass transport.

Thin Film Materials: Stress, Defect Formation and Surface Evolution

http://web.mit.edu/durint/PDF/Dao_et_alFR.pdf

Computational modeling of the forward and reverse problems in instrumented sharp indentation

A class of phenomenological strain gradient plasticity theories is formulated to accommodate more than one material length parameter. The objective is a generalization of the classical J2 3ow theory of plasticity to account for strain gradient e4ects that emerge in deformation phenomena at the micron scale. A special case involves a single length parameter and is of similar form to that proposed by Aifantis and co-workers. Distinct computational advantages are associated with this class of theories that make them attractive for applications requiring the generation of numerical solutions. The higher-order nature of the theories is emphasized, involving both higher-order stresses and additional boundary conditions. Competing members in the class of theories will be examined in light of experimental data on wire torsion, sheet bending, indentation and other micron scale plasticity phenomena. The data strongly suggest that at least two distinct material length parameters must be introduced in any phenomenological gradient plasticity theory, one parameter characterizing problems for which stretch gradients are dominant and the other relevant to problems when rotation gradients (or shearing gradients) are controlling. Flow and deformation theory versions of the theory are highlighted that can accommodate multiple length parameters. Examination of several basic problems reveals that the new formulations predict quantitatively similar plastic behavior to the theory proposed earlier by the present authors. The new formulations improve on the earlier theory in the manner in which elastic and plastic strains are decomposed and in the representation of behavior in the elastic range. ? 2001 Elsevier Science Ltd. All rights reserved.

http://www-mech.eng.cam.ac.uk/profiles/fleck/papers/143.pdf

A reformulation of strain gradient plasticity

Using Model Based Design as an Enabler for Digital Validation of Discrete State Machines in Regulated Manufacturing Environments

Crack growth in an elastic-plastic material and effects on near tip constraint

A comprehensive review of through thickness transverse residual stress distributions in a range of as-welded and mechanically bent components made up of a range of steels has been carried out. The geometries consisted of welded pipe butt joints, pipe on plate joints, tubular Y-joints, tubular T-joints and T-plate joints as well as in cold bent tubes and pipes and the collected data cover a range of engineering steels including ferritic, austenitic, C-Mn and Cr-Mo steels. Measured residual stress data, normalised with respect to the parent material yield stress, have shown a good linear correlation versus the normalised crack depth (of upto half thickness) of the region containing the residual stress resulting from the welding or cold-bending operation. The proposed simplified generic residual stress profiling based on a family of linear distribution lines, derived from the mean statistical linear fit of all the analysed data, is shown to provide different levels of conservatism on the calculated stress intensity factors. Whereas the profiles in assessment procedures are fixed and case specific the proposed linear method can be varied by a combination of mean and bending shifts from the mean regression line to produce lower or higher safety factors on stress intensity factor values depending on the level of safety required.Copyright © 2004 by ASME

Simplified Method for Profiling Residual Stress Distributions in Plate and Pipe Components

Engineering Critical Assessment of Embedded Flaws in Undermatch Pipeline Girth Welds

In the present paper, the mode I fracture toughness properties of a thermoplastic composite resin reinforced with glass fibres are experimentally evaluated. The neat resin is initially characterized in terms of static and mode I fracture toughness properties. Then three sets of panels are manufactured and tested: reference panels made of untreated glass fibres and the thermoplastic resin; UV treated glass fibres reinforced thermoplastic panels and plasma treated glass fibres reinforced thermoplastic panels. The effect of the treatment on the interfacial adhesion strength between fibres and matrix is characterized by a push-out test. An overall increase of the interfacial strength leads to an overall decrease of the composite mode I fracture toughness evaluated by Double Cantilever Beam (DCB) tests. Optical and Scanning Electron Microscopy images of the fracture surfaces are acquired and used to obtain a better interpretation of the fracture mechanisms. 

Noel P. O’Dowd

Papers

Using Model Based Design as an Enabler for Digital Validation of Discrete State Machines in Regulated Manufacturing Environments

Crack growth in an elastic-plastic material and effects on near tip constraint

Simplified Method for Profiling Residual Stress Distributions in Plate and Pipe Components

Engineering Critical Assessment of Embedded Flaws in Undermatch Pipeline Girth Welds

Mode I fracture toughness of glass fibre reinforced thermoplastic composites after UV and atmospheric plasma treatments