Non-Local Model Analysis of Heat Pulse Propagation and Simulation of Experiments in W7-AS

1999 ◽  
Vol 68 (2) ◽  
pp. 478-486 ◽  
Author(s):  
Takuya Iwasaki ◽  
Sanae-I. Itoh ◽  
Masatoshi Yagi ◽  
Kimitaka Itoh ◽  
Ulich Stroth
Keyword(s):  
Pulse Propagation ◽  
Model Analysis ◽  
Heat Pulse ◽  
Local Model ◽  
Non Local

On velocity selection for needle-crystals in a fully non-local model of solidification

1987 ◽  
Vol 48 (4) ◽  
pp. 547-552 ◽  
Author(s):  
B. Caroli ◽  
C. Caroli ◽  
C. Misbah ◽  
B. Roulet
Keyword(s):  
Local Model ◽  
Non Local ◽  
Selection For ◽  
Velocity Selection

Local and non-local damage model with extended stress decomposition for concrete

2021 ◽  
pp. 105678952199872
Author(s):  
Bilal Ahmed ◽  
George Z Voyiadjis ◽  
Taehyo Park
Keyword(s):  
Shear Stress ◽  
Degrees Of Freedom ◽  
Biaxial Loading ◽  
Damage Model ◽  
Local Model ◽  
Uniaxial Tensile ◽  
Gradient Theory ◽  
Principal Stresses ◽  
Stress Decomposition ◽  
Non Local

In this work, a new damage model for concrete is proposed with an extension of the stress decomposition (limited to biaxial cases), to capture shear damage due to the opposite signed principal stresses. To extract the pure shear stress, the assumption is made that one component of the shear stress is a minimum absolute of the two principal stresses. The opposite signed principal stresses are decomposed into shear stress and uniaxial tensile/compressive stress. A local model is implemented in Abaqus UMAT and it is further extended to a non-local model by utilization of the gradient theory. The concept of three length scales (tension, compression, and shear) is kept the same as the recently proposed nonlocal damage model by the authors. The nonlocal model is implemented in the Abaqus UEL-UMAT subroutine with an eight-node quadrilateral user-defined element, having five degrees of freedom at corner nodes (displacement in X/Y direction and tensile/compressive and shear nonlocal equivalent strain) and two degrees of freedom at internal nodes. Some examples of a local model including uniaxial and biaxial loading are addressed. Also, five examples of mixed crack mode and mode-I cracking are presented to comprehensively show the performance of this model.

A non-local model to analyse 2D and 3D microbuckling of long carbon fibre epoxy material

2021 ◽  
pp. 114531
Author(s):  
Jean-Claude Grandidier ◽  
Anil Bettadahalli Channakeshava ◽  
Roberta Mazziotta
Keyword(s):  
Carbon Fibre ◽  
Local Model ◽  
Epoxy Material ◽  
Non Local ◽  
2D And 3D

Does Science have to be Causal in Order to be Science? Reflections on Nina Azari's Questions

2009 ◽  
Vol 31 (3) ◽  
pp. 315-318
Author(s):  
Harald Walach
Keyword(s):  
Local Model ◽  
Non Local

Nina Azari in her commentary on our article in this issue “Spirituality: The Legacy of Parapsychology” has raised the issue of what it actually takes for something to be called science. Does causality come into the picture? If so, how does causality relate to our non-local model that seems to explicitly eschew the question of causality? The answer lies in what one is willing to accept as causality. If causality can be conceived broader than just efficient-mechanistic causality then certainly our model is causal. If one insists on efficient-mechanistic causality as the only and truly scientific notion of causality, it is not. But then, I would argue, this is a very restricted and also short sighted view which should be questioned, and eventually, disregarded. This is what we have set out to do.

Heat Pulse Propagation Along Silicon Nanofilms

2012 ◽  
Author(s):  
Yanbao Ma
Keyword(s):  
Thin Film ◽  
Heat Conduction ◽  
Numerical Model ◽  
Knudsen Number ◽  
Pulse Propagation ◽  
Heat Pulse ◽  
Phonon Transport ◽  
Similarity Parameter ◽  
Ballistic Phonons ◽  
Thermal Pulses

Recent advances in nanotechnology create a demand for greater scientific understanding of the transient ballistic phonon transport at the nanoscale. It is believed that ballistic phonons may travel for long distances without destruction, but it is unclear how far they can travel. Here, a numerical model is developed to study phonon transport in silicon nanofilms. It is elucidated how thermal pulses are transmitted in silicon nanofilms by longitudinal, ballistic transverse and dispersive transverse phonons. It is found that both ballistic longitudinal and ballistic transverse phonons are highly dissipative so they can only travel for short distances, while dispersive transverse phonons at lower frequencies are less dissipative and can travel for longer distances. There exists a similarity parameter (Knudsen number) in thin-film heat conduction with different thicknesses.

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