The role of inclusion-matrix boundaries in steels fracture processes

2021 ◽  
pp. 42-47
Author(s):  
S. I. Gubenko ◽  
E. V. Parusov ◽  
O. V. Parusov
Keyword(s):  
Fracture Processes ◽  
Inclusion Matrix

scholarly journals The role of aggregate granulation on testing fracture properties of concrete

2021 ◽  
Vol 15 (58) ◽  
pp. 376-385
Author(s):  
Marta Słowik
Keyword(s):  
Fracture Process ◽  
Process Zone ◽  
Concrete Structures ◽  
Cement Matrix ◽  
Hardened Cement ◽  
Professional Literature ◽  
Fracture Properties ◽  
Material Fracture ◽  
Fracture Processes

Concrete is a porous material containing aggregate of different sizes, hardened cement matrix with air pores, microcracks and water. Concrete internal structure is different from that of other engineering materials. Furthermore concrete is described as quazi-brittle material. Fracture processes in it form in a way that does not fit within classical theories. Therefore, to describe failure of concrete structures nonlinear fracture mechanics is often applied with success. Basic concrete parameters, like compressive and tensile strength, and modulus of elasticity, are not enough to analyze fracture processes in concrete structures. Additional fracture properties should be tested, among them fracture energy, complete diagram of stress-deformation under axial tension and the width of fracture process zone. Recognizing and testing fracture parameters is of paramount importance when analysing fracture process in concrete structures. The correct data of material’s properties and the adequate fracture model applied in numerical simulations influence final results. In the paper the findings reported in the professional literature are summarized and obtained results of the own numerical simulation are reported in order to  give a deeper knowledge on the role of aggregate on fracture properties of concrete.

scholarly journals Low-Cycle Fatigue of FRP Strips Glued to a Quasi-Brittle Material

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7753
Author(s):  
Enzo Martinelli ◽  
Antonio Caggiano
Keyword(s):  
Bond Length ◽  
Low Cycle Fatigue ◽  
Cyclic Behavior ◽  
Pure Mode ◽  
Geometric Quantity ◽  
Bond Slip ◽  
Frp Strips ◽  
Interface Bond ◽  
Fracture Processes

This paper aims at further advancing the knowledge about the cyclic behavior of FRP strips glued to quasi-brittle materials, such as concrete. The results presented herein derive from a numerical model based on concepts of based on fracture mechanics and already presented and validated by the authors in previous works. Particularly, it assumes that fracture processes leading to debonding develop in pure mode II, as is widely accepted in the literature. Starting from this assumption (and having clear both its advantages acnd shortcomings), the results of a parametric analysis are presented with the aim of investigating the role of both the mechanical properties of the interface bond–slip law and a relevant geometric quantity such as the bond length. The obtained results show the influence of the interface bond–slip law and FRP bond length on the resulting cyclic response of the FRP-to-concrete joint, the latter characterized in terms of S-N curves generally adopted in the theory of fatigue. Far from deriving a fully defined correlation among those parameters, the results indicate general trends that can be helpful to drive further investigation, both experimental and numerical in nature.

Effective Conductivity of a Composite in a Primitive Tetragonal Lattice of Highly Conducting Spheres in Resistive Thermal Contact With the Isolating Matrix

2007 ◽  
Vol 129 (12) ◽  
pp. 1617-1626 ◽  
Author(s):  
Cristina Filip ◽  
Bertrand Garnier ◽  
Florin Danes
Keyword(s):  
Effective Conductivity ◽  
Thermal Contact ◽  
Kapitza Resistance ◽  
Imperfect Contact ◽  
Leading Role ◽  
Surrounding Matrix ◽  
Tetragonal Lattice ◽  
Inclusion Matrix ◽  
Anisotropic Conduction

A state-of-the-art study and a physical and numerical 3D finite element study of anisotropic conduction through composites filled with isometric inclusions of different conductivity were performed by modeling the longitudinal conduction across a tetragonal lattice of spheres in imperfect contact with the surrounding matrix. In dimensionless variables, the effective conductivity E is expressible as a function of a geometrical parameter B, reflecting the relative thickness of the gap between spheres, the Kapitza resistance C of the contact inclusion/matrix, and the relative resistivity D of the filler. The computation of some 600 E values at some 25 levels of the factors B, C, and D allows one to find some features, such as the leading role of the factor whose value is the highest of three, the low effect of the interactions between factors, the imperfect equivalence of the effects of the three factors, the slow and linear E dependence on the second and third greatest factor, and finally, the asymptotically exact linear relationship between E and the logarithmated sum of factors, with a slope depending only slightly on the relative magnitudes of factors.

scholarly journals Fluctuations and nonlinear oscillations in complex natural systems

2018 ◽  
Vol 62 ◽  
pp. 02006
Author(s):  
Boris Shevtsov ◽  
Olga Shevtsova
Keyword(s):  
Nonlinear Oscillations ◽  
Thunderstorm Activity ◽  
Collective Effects ◽  
Chaotic Oscillations ◽  
Natural Systems ◽  
Lightning Discharges ◽  
Cascade Processes ◽  
Fracture Processes ◽  
Resonance Propagation

Resonance propagation of radiation in the ionosphere, solar activity, magnetic dynamos, lightning discharges, fracture processes, plastic deformations, seismicity, turbulence and hydrochemical variability are considered as examples of complex dynamical systems in which similar fluctuation and nonlinear oscillation regimes arise. Collective effects in the systems behavior and chaotic oscillations in individual subsystems, the ratio of random and deterministic, the analysis of variability factors and the change of dynamic regimes, the scaling relation between the elements of the system and the interaction of scales are discussed. It is shown that consolidation and branching in disruptions or thunderstorm activity is the transfer of disturbances to up and down of cascades as in turbulence, and the alpha-omega effects of the magnetic dynamo are the same cascade processes, but in the presence of an external magnetic field or rotation that removes the degeneracy in the system by directions. Particular attention is paid to natural generators and oscillation amplifiers, in which the Lorentz triplet plays the role of a universal model of a nonlinear oscillator.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

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