Phoebus Rosakis, Ares J. Rosakis,
Tópico(s): Composite Material Mechanics
1988 - Springer Science+Business Media | Journal of Elasticity
Phoebus Rosakis, Ares J. Rosakis, G. Ravichandran, J. Hodowany,
The energy balance equation for elastoplastic solids includes heat source terms that govern the conversion of some of the plastic work into heat. The remainder contributes to the stored energy of cold work due to the creation of crystal defects. This paper is concerned with the fraction β of the rate of plastic work converted into heating. We examine the status of the common assumption that β is a constant with regard to the thermodynamic foundations of thermoplasticity and experiments. A general ...
Tópico(s): Microstructure and mechanical properties
2000 - Elsevier BV | Journal of the Mechanics and Physics of Solids
Xiaomin Deng, Ares J. Rosakis,
... factor and the crack propagation speed. These relations are found to agree well with experimental measurements by Rosakis et al. (J. Mech. Phys. Solids 32, 443, 1984) and by ...
Tópico(s): High-Velocity Impact and Material Behavior
1991 - Elsevier BV | Journal of the Mechanics and Physics of Solids
Cheng Liu, Ares J. Rosakis, L. B. Freund,
... J. Mech. Phys. Solids40(3), 699–719) and Rosakis et al. (1991, Int. J. Fract. 50, R39–R45), in which dynamic transient effects were included in the near-tip deformation field, the exact mapping equations of caustics are derived for non-uniformly propagating cracks. The resulting ...
Tópico(s): Optical measurement and interference techniques
1993 - Elsevier BV | International Journal of Solids and Structures
Xue Feng, Yonggang Huang, Ares J. Rosakis,
... strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. Recently Huang, Rosakis, and co-workers [Acta Mech. Sinica, 21, pp. 362–370 (2005); J. Mech. Phys. Solids, 53, 2483–2500 (2005); Thin ...
Tópico(s): Metal and Thin Film Mechanics
2007 - ASM International | Journal of Applied Mechanics
M. Mello, Harish S. Bhat, Ares J. Rosakis, Hiroo Kanamori,
The near field ground motion signatures associated with sub-Rayleigh and supershear ruptures are investigated using the laboratory earthquake experiment originally developed by Rosakis and coworkers (Xia et al., 2004, 2005a; Lu et al., 2007; Rosakis et al., 2007). Heterodyne laser interferometers enable continuous, high bandwidth measurements of fault-normal (FN) and fault-parallel (FP) particle velocity "ground motion" records at discrete locations on the surface of a Homalite test specimen as a sub- ...
Tópico(s): Seismic Performance and Analysis
2010 - Elsevier BV | Tectonophysics
R. Narasimhan, Ares J. Rosakis,
A simultaneous numerical and experimental investigation is undertaken to assess three-dimensional effects and HRR dominance near a crack front in a ductile 3-point bend specimen. In parallel to the three-dimensional calculations, a plane-strain and a plane-stress analysis of the same in-plane specimen geometry is performed to obtain upper and lower bounds for the three-dimensional calculation. The radial, angular, and thickness variation of the stresses and displacements are studied in great detail ...
Tópico(s): Fatigue and fracture mechanics
1990 - ASM International | Journal of Applied Mechanics
Ares J. Rosakis, Sridhar Krishnaswamy, Hareesh V. Tippur,
Tópico(s): Non-Destructive Testing Techniques
1990 - Elsevier BV | Optics and Lasers in Engineering
Alan T. Zehnder, Ares J. Rosakis, Sridhar Krishnaswamy,
Tópico(s): High-Velocity Impact and Material Behavior
1990 - Springer Science+Business Media | International Journal of Fracture
Alan T. Zehnder, Ares J. Rosakis,
Tópico(s): Metal Forming Simulation Techniques
1990 - Springer Science+Business Media | International Journal of Fracture
R. Narasimhan, Ares J. Rosakis, John F. Hall,
A detailed finite element study of stable crack growth in elastic-perfectly plastic solids obeying an incremental plasticity theory and the Huber-Von Mises yield criterion is performed under plane stress, small-scale yielding conditions. A nodal release procedure is used to simulate crack extension under continuously increasing external load. It is found that the asymptotic angular extent of the active plastic zone surrounding the moving crack tip is from θ = 0 deg to about θ = 45 deg. Clear evidence ...
Tópico(s): Fatigue and fracture mechanics
1987 - ASM International | Journal of Applied Mechanics
Francisco G. Benítez, Ares J. Rosakis,
Tópico(s): Numerical methods in engineering
1987 - Springer Science+Business Media | Journal of Elasticity
R. Narasimhan, Ares J. Rosakis, John F. Hall,
A detailed finite element analysis is performed to model quasi-static crack growth under plane stress, small-scale yielding conditions in elastic-plastic materials characterized by isotropic power law hardening and the Huber-Von Mises yield surface. A nodal release procedure is used to simulate crack extension. Results pertaining to the influence of hardening on the extent of active yielding and the near-tip stress and deformation fields are presented. Clear evidence of an elastic unloading wake ...
Tópico(s): High-Velocity Impact and Material Behavior
1987 - ASM International | Journal of Applied Mechanics
Alan T. Zehnder, Ares J. Rosakis,
Tópico(s): Advanced Measurement and Metrology Techniques
1986 - Springer Science+Business Media | International Journal of Fracture
Ares J. Rosakis, K. Ravi‐Chandar,
The extent of the region of three-dimensionality of the crack-tip stress field is investigated using reflected and transmitted caustics. The range of the applicability of two-dimensional near tip solutions is thus established experimentally. The experiments are performed using Plexiglass and high-strength 4340-steel compact tension specimens. A wide spectrum of thicknesses is investigated. At each thickness, measurements are performed at a variety of distances r from the crack tip, ranging from ...
Tópico(s): Ultrasonics and Acoustic Wave Propagation
1986 - Elsevier BV | International Journal of Solids and Structures
R. Narasimhan, Ares J. Rosakis,
Tópico(s): High-Velocity Impact and Material Behavior
1988 - Elsevier BV | Journal of the Mechanics and Physics of Solids
Ares J. Rosakis, Alan T. Zehnder, R. Narasimhan,
Applications of the method of reflected caustics to the measurement of the J integral in ductile materials are reviewed. It is demonstrated, both numerically and experimentally, that the conditions for accurate interpretation of caustics on the basis of plane stress small scale yielding analyses are often overrestrictive. To overcome these restrictions, we used a three-dimensional, elastic-plastic finite-element calculation to analyze caustics formed by reflection of light from a particular test ...
Tópico(s): Advanced Measurement and Metrology Techniques
1988 - SPIE | Optical Engineering
Xiao Lu, N. Lapusta, Ares J. Rosakis,
We consider the effect of the rupture initiation procedure on supershear transition of Mode II ruptures on interfaces governed by linear slip-weakening friction. Our study is motivated by recent experiments, which demonstrated the transition of spontaneous ruptures from sub-Rayleigh to supershear speeds in the laboratory. In these works the experiments were analysed using the Burridge–Andrews model of supershear transition, in which a supershear daughter crack is nucleated in front of the main mother ...
Tópico(s): Seismic Performance and Analysis
2009 - Oxford University Press | Geophysical Journal International
Carl‐Ernst Rousseau, Ares J. Rosakis,
Building upon previous laboratory earthquake experiments of dynamic shear rupture growth taking place along faults with simple kinks, new and complex fault geometries involving cohesively held fault branches are studied. Asymmetric impact at the specimen boundaries controls the incoming shear ruptures, which are manipulated to propagate at either sub‐Rayleigh or supershear velocities. High‐speed photography and dynamic photoelasticity are used with a model material, Homalite‐100, to monitor incoming ...
Tópico(s): Seismic Imaging and Inversion Techniques
2009 - American Geophysical Union | Journal of Geophysical Research Atmospheres
W. A. Griffith, Ares J. Rosakis, David D. Pollard, C.W. KO,
Research Article| September 01, 2009 Dynamic rupture experiments elucidate tensile crack development during propagating earthquake ruptures W. Ashley Griffith; W. Ashley Griffith 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA *Current address: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy; E-mail: griffith@ingv.it. Search for other works by this author on: GSW Google Scholar Ares Rosakis; Ares ...
Tópico(s): Seismic Performance and Analysis
2009 - Geological Society of America | Geology
E. L. Templeton, A. Baudet, Harsha S. Bhat, Renata Dmowska, J. R. Rice, Ares J. Rosakis, Carl‐Ernst Rousseau,
We analyze the nucleation and propagation of shear cracks along nonplanar, kinked, and branched fault paths corresponding to the configurations used in recent laboratory fracture studies by Rousseau and Rosakis (2003, 2009). The aim is to reproduce numerically those shear rupture experiments and from that provide an insight into processes which are active when a crack, initially propagating in mode II along a straight path, interacts with a bend in the fault or a branching junction. The experiments ...
Tópico(s): Seismic Imaging and Inversion Techniques
2009 - American Geophysical Union | Journal of Geophysical Research Atmospheres
C. G. Sammis, Ares J. Rosakis, Harsha S. Bhat,
Tópico(s): Seismic Waves and Analysis
2009 - Birkhäuser | Pure and Applied Geophysics
Hareesh V. Tippur, Sridhar Krishnaswamy, Ares J. Rosakis,
Tópico(s): Fatigue and fracture mechanics
1991 - Springer Science+Business Media | International Journal of Fracture
Alan T. Zehnder, Ares J. Rosakis,
The heat generated due to plastic deformation at the tip of a dynamically propagating crack in a metal causes a large local temperature increase at the crack tip which is expected to affect the selection of failure modes during dynamic fracture and to thus influence the fracture toughness of the material. The distribution of temperature at the tips of dynamically propagating cracks in two heat treatments of AISI 4340 carbon steel was investigated experimentally using an array of eight high speed ...
Tópico(s): Fatigue and fracture mechanics
1991 - Elsevier BV | Journal of the Mechanics and Physics of Solids
Hareesh V. Tippur, Sridhar Krishnaswamy, Ares J. Rosakis,
A first order diffraction analysis of an optical interferometer, Coherent Gradient Sensor (CGS), for measuring surface gradients is presented. Its applicability in the field of fracture mechanics is demonstrated by quantitatively measuring the gradients of out-of-plane displacements around a crack tip in a three point bent fracture specimen under static loading. This method has potential for the study of deformation fields near a quasi-statically or dynamically growing crack.
Tópico(s): Numerical methods in engineering
1991 - Springer Science+Business Media | International Journal of Fracture
Sridhav Krishnaswamy, Ares J. Rosakis, G. Ravichandran,
In Part I of this paper, the question of the extent of dominance of the mode I asymptotic elastodynamic crack-tip field (the KdI-field) was studied experimentally. Here, the results of two and three-dimensional elastodynamic finite element simulations of the drop-weight experiments are reported. The load records as obtained from the impact hammer and supports of the drop-weight loading device were used as boundary tractions in the numerical simulations. For the laboratory specimen studied, the results ...
Tópico(s): Transportation Safety and Impact Analysis
1991 - ASM International | Journal of Applied Mechanics
Sridhar Krishnaswamy, Ares J. Rosakis,
The question of the domain of dominance of mode I asymptotic elastodynamic crack-tip fields is investigated experimentally for the cases of dynamically loaded stationary cracks as well as dynamically propagating cracks. The experiments reported are on three-point bend specimens loaded dynamically using a drop-weight tower. An optical configuration leading to a bifocal high-speed camera is proposed. This is used in conjunction with the method of caustics to obtain apparent dynamic stress intensity ...
Tópico(s): High-Velocity Impact and Material Behavior
1991 - ASM International | Journal of Applied Mechanics
Hareesh V. Tippur, Ares J. Rosakis,
Tópico(s): Structural Health Monitoring Techniques
1991 - Springer Nature | Experimental Mechanics
Ares J. Rosakis, Cheng Liu, L. B. Freund,
Tópico(s): Elasticity and Wave Propagation
1991 - Springer Science+Business Media | International Journal of Fracture
Sridhar Krishnaswamy, Hareesh V. Tippur, Ares J. Rosakis,
A shearing interferometric method (CGS) is proposed as a viable alternative to currently used experimental techniques for the study of dynamic crack propagation in both transparent and opaque media. CGS is a full-field optical technique that provides real-time fringes representing crack-tip deformation or stress state. The results of the experiments are interpreted on the basis of the conventional singular asymptotic analysis as well as a newly developed transient higher-order asymptotic analysis. ...
Tópico(s): Surface Treatment and Residual Stress
1992 - Elsevier BV | Journal of the Mechanics and Physics of Solids