A practical meshfree inverse method for identification of thermo-mechanical fracture load of a body by examining the crack path in the body

2021 ◽  
Vol 133 ◽  
pp. 236-247
Author(s):  
F. Liaghat ◽  
A. Khosravifard ◽  
M.R. Hematiyan ◽  
T. Rabczuk
Keyword(s):  
Inverse Method ◽  
Crack Path ◽  
Fracture Load ◽  
The Body ◽  
Mechanical Fracture

scholarly journals Brittle fracture in a periodic structure with internal potential energy

2014 ◽  
Vol 470 (2165) ◽  
pp. 20130821 ◽  
Author(s):  
Gennady S. Mishuris ◽  
Leonid I. Slepyan
Keyword(s):  
Brittle Fracture ◽  
Energy Level ◽  
Periodic Structure ◽  
Crack Path ◽  
The Body ◽  
Initial State ◽  
Combined Action ◽  
External Forces ◽  
Internal Potential ◽  
Discrete Transform

We consider a brittle fracture taking account of self-equilibrated distributed stresses existing at microlevel in the absence of external forces. To determine how the latter can affect the crack equilibrium and growth, a model of a structured linearly elastic body is introduced, consisting of two equal symmetrically arranged layers (or half-planes) connected by an interface as a prospective crack path. The interface comprises a discrete set of elastic bonds. In the initial state, the bonds are assumed to be stressed in such a way that tensile and compressive forces of the same value alternate. In the general considerations, the layers are assumed to be of an unspecified periodic structure, where such self-equilibrated stresses may also exist. A two-line chain and a lattice are examined as the specified structure. We consider the states of the body-with-a-crack under such microlevel stresses (MS) and under a combined action of the remote forces and MS. Analytical solutions to the considered problems are presented based on the introduction of a selective discrete transform. We demonstrate that MS can increase as well as decrease the crack resistance depending on the internal energy level. We also discuss different scenarios of the crack growth.

Semi-inverse method à la Saint-Venant for two-dimensional linear isotropic homogeneous second-gradient elasticity

2015 ◽  
Vol 22 (5) ◽  
pp. 919-937 ◽  
Author(s):  
Luca Placidi ◽  
Amr Ramadan El Dhaba
Keyword(s):  
Inverse Method ◽  
Three Dimensional ◽  
Gradient Elasticity ◽  
The Body ◽  
Divergence Theorem ◽  
Gradient Material ◽  
Two Dimensional ◽  
Isotropic Materials ◽  
Second Gradient

This semi-inverse method is similar to that used in the so-called Saint-Venant problem for cylindrical three-dimensional first-gradient linear homogeneous and isotropic materials. This semi-inverse method is similar to that used by Saint-Venant to solve the omonimus problem for cylindrical three-dimensional first-gradient linear homogeneous and isotropic materials. Two examples are also presented. It is found that wedge forces are necessary to maintain the body in equilibrium and that these are not an artefact of the double application of the divergence theorem in the second-gradient material derivations.

Simplified frequency‐domain expressions for potential fields of arbitrary three‐dimensional bodies

Geophysics ◽  
1988 ◽  
Vol 53 (3) ◽  
pp. 365-374 ◽  
Author(s):  
R. O. Hansen ◽  
Xiaomu Wang
Keyword(s):  
Inverse Method ◽  
Three Dimensional ◽  
The Body ◽  
Potential Fields ◽  
Great Flexibility ◽  
Special Position ◽  
Computational Overhead ◽  
Gravity And Magnetic ◽  
Analytic Expressions ◽  
Polyhedral Bodies

Models based on homogeneous polyhedral bodies offer great flexibility in representing the potential fields of complex geologic sources. However, existing expressions for the gravity and magnetic fields of such bodies suffer from two disadvantages. First, the surface of the body must be specified as a set of triangular facets, which makes input to a modeling program rather awkward. Second, each facet of the body must be rotated into a special position, which generates substantial computational overhead and makes the analytic expressions difficult to interpret. In this paper, Pedersen’s Fourier transform expressions for the potential fields due to homogeneous polyhedral bodies are recast in a simpler, coordinate‐invariant form. The resulting expressions are then rewritten as a sum of contributions from each vertex of the body. This greatly simplified form is used as the basis for a modeling program that is substantially faster and more straightforward than existing programs. Furthermore, the analytic expressions promise to be useful for further investigation of an inverse method based on polyhedral‐body models.

An Inverse Method for the Design of Bodies of Revolution by Boundary Integral Modelling

1991 ◽  
Vol 205 (2) ◽  
pp. 91-97 ◽  
Author(s):  
R I Lewis
Keyword(s):  
Inverse Method ◽  
Body Shape ◽  
Axisymmetric Flow ◽  
Vortex Sheet ◽  
Boundary Integral ◽  
The Body ◽  
Boundary Integral Method ◽  
Bodies Of Revolution ◽  
Final Design ◽  
Induced Flow

A surface vorticity boundary integral method is presented for the design of bodies of revolution in axisymmetric flow. The analysis finds the desired body shape to deliver a prescribed surface potential flow velocity or pressure distribution. To achieve this the body surface is simulated by a flexible vorticity sheet of prescribed strength. Starting from an arbitrary first guess for the body shape, normally an ellipsoid, the flexible vortex sheet is successively realigned with its own self-induced flow field during an iterative process which converges accurately onto the desired shape. A well-proven analysis method is also presented for back-checking the final design.

scholarly journals Physiological and Transcriptional Responses in Weaned Piglets Fed Diets with Varying Phosphorus and Calcium Levels

Nutrients ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 436 ◽  
Author(s):  
Christian Gerlinger ◽  
Michael Oster ◽  
Luisa Borgelt ◽  
Henry Reyer ◽  
Eduard Muráni ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Fracture Load ◽  
Weaned Piglets ◽  
Mineral Density ◽  
Transcriptional Responses ◽  
Peripheral Blood Mononuclear ◽  
Mechanical Fracture ◽  
P Utilization ◽  
The Many ◽  
Mineral Levels

Phosphorus (P) is an important element of various metabolic and signalling processes, including bone metabolism and immune function. To elucidate the routes of P homeostasis and utilization, a five-week feeding study was conducted with weaned piglets receiving a diet with recommended amounts of P and Ca (M), or a diet with lower (L) or higher (H) P values and a constant Ca:P ratio. Routes of P utilization were deduced via bone characteristics (MicroCT), genome-wide transcriptomic profiles of peripheral blood mononuclear cells (PBMCs), and serum mineral levels. MicroCT revealed significantly lower bone mineral density, trabecular number, and mechanical fracture load in (L). Gene expression analyses showed transcripts of 276 and 115 annotated genes with higher or lower abundance in (H) than (L) that were related to basic cellular and metabolic processes as well as response to stimuli, developmental processes and immune system processes. This study shows the many molecular routes involved in P homeostasis that should be considered to improve endogenous mechanisms of P utilization.

Representing utility and deploying the body

2020 ◽  
Vol 43 ◽  
Author(s):  
David Spurrett
Keyword(s):  
Functional Activity ◽  
Degrees Of Freedom ◽  
The Body ◽  
Target Article ◽  
Processing Demands ◽  
The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

Neuron-glia relationship during the early postembryonic development of the nervous system in some oligochaetes

1978 ◽  
Vol 36 (2) ◽  
pp. 600-601
Author(s):  
Wiktor Djaczenko ◽  
Carmen Calenda Cimmino
Keyword(s):  
Nervous System ◽  
Glial Cells ◽  
Early Period ◽  
Postembryonic Development ◽  
Ruthenium Red ◽  
The Body ◽  
Tubifex Tubifex ◽  
Growth Stages ◽  
Cell Processes ◽  
Cytoplasmic Processes

The simplicity of the developing nervous system of oligochaetes makes of it an excellent model for the study of the relationships between glia and neurons. In the present communication we describe the relationships between glia and neurons in the early periods of post-embryonic development in some species of oligochaetes.Tubifex tubifex (Mull. ) and Octolasium complanatum (Dugès) specimens starting from 0. 3 mm of body length were collected from laboratory cultures divided into three groups each group fixed separately by one of the following methods: (a) 4% glutaraldehyde and 1% acrolein fixation followed by osmium tetroxide, (b) TAPO technique, (c) ruthenium red method.Our observations concern the early period of the postembryonic development of the nervous system in oligochaetes. During this period neurons occupy fixed positions in the body the only observable change being the increase in volume of their perikaryons. Perikaryons of glial cells were located at some distance from neurons. Long cytoplasmic processes of glial cells tended to approach the neurons. The superimposed contours of glial cell processes designed from electron micrographs, taken at the same magnification, typical for five successive growth stages of the nervous system of Octolasium complanatum are shown in Fig. 1. Neuron is designed symbolically to facilitate the understanding of the kinetics of the growth process.

Flagellar Attachment in Selected Trypanosomes

1973 ◽  
Vol 31 ◽  
pp. 496-497
Author(s):  
J. J. Paulin
Keyword(s):  
Cell Membrane ◽  
Lateral Surface ◽  
The Body ◽  
Flagellar Pocket ◽  
Integral Component ◽  
Free Flagellum ◽  
Flagellar Axoneme

Movement in epimastigote and trypomastigote stages of trypanosomes is accomplished by planar sinusoidal beating of the anteriorly directed flagellum and associated undulating membrane. The flagellum emerges from a bottle-shaped depression, the flagellar pocket, opening on the lateral surface of the cell. The limiting cell membrane envelopes not only the body of the trypanosome but is continuous with and insheathes the flagellar axoneme forming the undulating membrane. In some species a paraxial rod parallels the axoneme from its point of emergence at the flagellar pocket and is an integral component of the undulating membrane. A portion of the flagellum may extend beyond the anterior apex of the cell as a free flagellum; the length is variable in different species of trypanosomes.

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