A two-scale non-local model of swelling porous media incorporating ion size correlation effects

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.

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

Composite Structures ◽

10.1016/j.compstruct.2021.114531 ◽

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

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

Archive for the Psychology of Religion ◽

10.1163/008467209x12499946199489 ◽

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.

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