Multiscale Fracture Model for Quasi-Brittle Materials

2011 ◽  
Vol 82 ◽  
pp. 160-165 ◽  
Author(s):  
Yuri V. Petrov ◽  
Vladimir Bratov
Keyword(s):  
Experimental Data ◽  
Brittle Fracture ◽  
Experimental Determination ◽  
Fracture Process ◽  
Strength Properties ◽  
Material Strength ◽  
Scale Level ◽  
Scale Levels ◽  
Real Scale

Fracture of quasi-brittle heterogeneous materials is steered by processes at several different scale levels. These processes can progress independently or affect each other. In order to model fracture of such materials one should account for all rupture processes contributing to overall fracture process. This paper is presenting structural-temporal approach for analysis of multiscale nature of brittle fracture. Notion of spatial-temporal cell for different scale levels is introduced. Problem of experimental determination of a fixed scale level is discussed. Possible interconnections of this scale level with higher and lower scale levels are discussed. It is shown that this can give a possibility to predict fracture on a higher (real) scale level having experimental data obtained on a lower (laboratory) scale. This possibility is of extreme importance for many applications where the possibility to evaluate material strength properties on real structure scale level does not exist (ex. geological objects, big concrete structures, trunk pipelines, etc.).

Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Stoichiometric CH4/O2/N2-Mixtures and CH4/O2-Mixtures in Long Pipes

2016 ◽  
Author(s):  
Hans-Peter Schildberg
Keyword(s):  
Experimental Data ◽  
Experimental Determination ◽  
Process Design ◽  
Pressure Vessel ◽  
Gas Mixture ◽  
Detonation Pressure ◽  
Recent Past ◽  
Static Loads ◽  
Present Experimental Data

In the recent past (PVP2013-97677, PVP2014-28197, PVP2015-45286) we had started to determine the static equivalent pressures pstat of the eight detonative pressure scenarios in long and short pipes for different detonable gas mixtures. The pstat-values are of vital importance for process design: by assigning static equivalent pressures to the highly dynamic detonative pressure peaks it is possible to apply the established pressure vessel guidelines, which can only cope with static loads, for the design of detonation pressure resistant pipes. One important finding was that the ratio R between pstat at the location where transition from deflagration to detonation occurs and pstat in the region of the stable detonation strongly depends on the reactivity of the gas mixture. In this paper we present experimental data showing the variation of R over the entire explosive range of Methane/O2/N2 mixtures. Qualitatively, the results should be representative for all other combustible/O2/N2-mixtures. Furthermore, recommendations for estimating pstat values of short pipe scenarios on basis of the long pipe scenarios are given.

scholarly journals Experimental Determination of the Buckling Loads of Floating Ice Sheets

1983 ◽  
Vol 4 ◽  
pp. 260-265 ◽  
Author(s):  
D. S. Sodhi ◽  
F. D. Haynes ◽  
K. Kato ◽  
K. Hirayama
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Experimental Determination ◽  
Characteristic Length ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Experimental Results ◽  
Buckling Loads ◽  
Data Points

Experiments were performed to determine the forces required to buckle a floating ice sheet pushing against structures of different widths. The characteristic length of each ice sheet was determined to enable a comparison to be made between the theoretical and experimental results.Most of the experimental data points are within the range of the theoretical values of normalized buckling loads for frictionless and hinged boundary conditions, which represent the extreme situations for ice-structure contact. Thus, the agreement between the theoretical and experimental buckling loads is considered to be good. Photographs of the buckled ice sheets show a resemblance to the theoretical mode of buckling.

scholarly journals Experimental Determination of the Buckling Loads of Floating Ice Sheets

1983 ◽  
Vol 4 ◽  
pp. 260-265 ◽  
Author(s):  
D. S. Sodhi ◽  
F. D. Haynes ◽  
K. Kato ◽  
K. Hirayama
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Experimental Determination ◽  
Characteristic Length ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Experimental Results ◽  
Buckling Loads ◽  
Data Points

Experiments were performed to determine the forces required to buckle a floating ice sheet pushing against structures of different widths. The characteristic length of each ice sheet was determined to enable a comparison to be made between the theoretical and experimental results. Most of the experimental data points are within the range of the theoretical values of normalized buckling loads for frictionless and hinged boundary conditions, which represent the extreme situations for ice-structure contact. Thus, the agreement between the theoretical and experimental buckling loads is considered to be good. Photographs of the buckled ice sheets show a resemblance to the theoretical mode of buckling.

Experimental Determination of the Moment of Inertias of USM e-UAV

2013 ◽  
Vol 465-466 ◽  
pp. 368-372
Author(s):  
M. Haniff Junos ◽  
Nurulasikin Mohd Suhadis ◽  
Mahmud M. Zihad
Keyword(s):  
Experimental Data ◽  
Experimental Determination ◽  
Moment Of Inertia ◽  
Experimental Setup ◽  
Torsion Pendulum ◽  
The Moment ◽  
Pendulum Experiment

This paper presents the experimental determination of the moment of inertia of USM e-UAV by using pendulum method. Compound pendulum experiment is used to determine the moment of inertia about x and y axes while the moment of inertia about z-axis is determined using bifilar torsion pendulum method. An experimental setup is developed with appropriate dimension to accommodate USM e-UAV. Experimental data are presented and discussed.

Perpendicular-to-Grain Strength of Douglas-Fir

1975 ◽  
Vol 2 (1) ◽  
pp. 50-57 ◽  
Author(s):  
J. D. Barrett ◽  
R. O. Foschi ◽  
S. P. Fox
Keyword(s):  
Experimental Data ◽  
Brittle Fracture ◽  
Survival Probability ◽  
Douglas Fir ◽  
Curved Beams ◽  
Allowable Stresses ◽  
Laminated Material

Weibull's theory of brittle fracture is applied to the determination of strength of Douglas-fir wood in tension perpendicular to the grain. Results from tests on blocks of glued-laminated material uniformly stressed in tension are used to derive ultimate stresses, at a given survival probability, for pitched-tapered beams, curved beams, and griplam nail connections. The results of the theory are shown to be in agreement with experimental data. Allowable stresses are derived for blocks, pitched-tapered beams, curved beams, and the particular nailed connection studied.

scholarly journals Experimental Determination of the Friction Factor in a Tube with Internal Helical Ribs

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 257 ◽  
Author(s):  
Sławomir Grądziel ◽  
Karol Majewski
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Power Plant ◽  
Experimental Determination ◽  
Friction Factor ◽  
Contact Surface ◽  
Experimental Testing ◽  
New Correlation ◽  
Power Boiler

Due to the extended geometry of internally rifled tubes with helical ribs, the rate of convective heat transfer within them is much higher compared to smooth tubes. Simultaneously, a rise in the contact surface area between the fluid and the solid body increases the friction factor. This paper presents the results of experimental testing performed to determine the friction factor in an internally rifled tube with helical ribs. The tests were carried out on a purpose-built test stand. The tested object was a rifled tube used in the evaporator of a once-through supercritical power boiler operating in a power plant in Poland. The friction factor results obtained from testing are compared to the results of calculations performed by means of correlations known from the literature. Finally, using experimental data, a new correlation is developed that enables the determination of the friction factor in internally rifled tubes with helical ribs.

Experiment-Calculated Investigation of the Forced Convection of Nanofluids Using Single Fluid Approach

2014 ◽  
Vol 348 ◽  
pp. 123-138 ◽  
Author(s):  
Andrey V. Minakov ◽  
Alexander S. Lobasov ◽  
M.I. Pryazhnikov ◽  
D.V. Guzei
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Thermal Conductivity ◽  
Experimental Determination ◽  
Forced Convection ◽  
Navier Stokes ◽  
Physical Parameters ◽  
Hydrodynamic Description ◽  
Transfer Equations

An experiment-calculated investigation of forced convection of nanofluids based on Al2O3nanoparticles was carried out. The hydrodynamic description and a model of homogeneous nanofluids were used. The homogeneous nanofluids model assumes that the hydrodynamics and heat transfer can be described by conventional Navier-Stokes and heat transfer equations with the physical parameters corresponding to nanofluids. The results showed that this model very well described the experimental data in some cases. However, in some other cases, there are discrepancies between experiment and theory that can be explained by the real heterogeneity of nanofluids and the errors in the experimental determination of thermal conductivity and viscosity of nanofluids.

Experimental determination of the fracture process zone in concrete

1983 ◽  
Vol 13 (4) ◽  
pp. 557-567 ◽  
Author(s):  
Luigi Cedolin ◽  
Sandro Dei Poli ◽  
Ivo Iori
Keyword(s):  
Experimental Determination ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone
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