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Tanguy Messager - One of the best experts on this subject based on the ideXlab platform.
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analytical Modeling of synthetic fiber ropes part ii a Linear Elastic Model for 1 6 fibrous structures
International Journal of Solids and Structures, 2007Co-Authors: Seyed Reza Ghoreishi, Peter Davies, Patrice Cartraud, Tanguy MessagerAbstract:Abstract In part I of this study it was shown that, to Model synthetic fiber ropes, two scale transition Models can be used in sequence. The first Model (continuum Model) has been presented in the part I and the present paper examines the behavior of a fibrous structure consisting of 6 helicoidal strands around a central core (1 + 6 structure). An analytical Model will be presented which enables the global Elastic behavior of such a cable under tension–torsion loading to be predicted. In this Model, first, the core and the strands are described as Kirchhoff–Love beams and then the traction–torsion coupling behavior is taken into account for both of them. By Modeling the contact conditions between the strands and the core, with certain assumptions, it is possible to describe the behavior of the cable section as a function of the degrees of freedom of the core. The behavior of the cable can thus be deduced from the tension–torsion coupling behavior of its constituents. Tensile tests have been performed on the core, the strands and then on a full scale 205 ton failure load cable. Finally, predicted stiffness from the analytical Models is compared to the test results.
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Analytical Modeling of synthetic fiber ropes. Part II : A Linear Elastic Model for 1 + 6 fibrous structures
International Journal of Solids and Structures, 2007Co-Authors: Seyed Reza Ghoreishi, Peter Davies, Patrice Cartraud, Tanguy MessagerAbstract:In part I of this study it was shown that, to Model synthetic fiber ropes, two scale transition Models can be used in sequence. The first Model (continuum Model) has been presented in the part I and the present paper examines the behavior of a fibrous structure consisting of 6 helicoidal strands around a central core (1 + 6 structure). An analytical Model will be presented which enables the global Elastic behavior of such a cable under tension-torsion loading to be predicted. In this Model, first, the core and the strands are described as Kirchhoff-Love beams and then the traction-torsion coupling behavior is taken into account for both of them. By Modeling the contact conditions between the strands and the core, with certain assumptions, it is possible to describe the behavior of the cable section as a function of the degrees of freedom of the core. The behavior of the cable can thus be deduced from the tension-torsion coupling behavior of its constituents. Tensile tests have beer, performed on the core, the strands and then on a full scale 205 ton failure load cable. Finally, predicted stiffness from the analytical Models is compared to the test results.
Shengli Chen - One of the best experts on this subject based on the ideXlab platform.
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Quick approximate elastoplastic solutions of wellbore stability problems based on numerical simulation and statistical analysis
Journal of Natural Gas Science and Engineering, 2018Co-Authors: Chang Huang, Babak Akbari, Shengli ChenAbstract:Abstract Wellbore instability has been a chronic issue for well operators over several decades in petroleum industry. Traditional Linear Elastic Models may sometimes fail to provide a proper mud weight window for drilling engineers. Elastoplastic Models can better represent the rock behavior and, therefore, more accurately evaluate the risk of wellbore instability. However, elastoplastic Models have failed to gain popularity in the industry because of the Model complexity and computation cost. This work proposes an approximating method in a novel manner, incorporating both the validity of the elastoplastic constitutive Model and the rapidity of the Linear Elastic Model to predict wellbore behavior. The non-associative strain hardening Drucker-Prager elastoplastic Model is used. The relationship between the yielded zone area calculated by the elastoplastic Model and the pseudo-yielded zone area calibrated by the Linear Elastic Model is statistically investigated. It is found that the two can be correlated with high confidence based on a set of common input parameters, like in-situ stresses, wellbore pressure, Young's Modulus, etc. Three correlation equations are provided according to the value range of the predicting terms and an application example is addressed at the end. In conclusion, this approach will help engineers make reliable wellbore stability decisions without resorting to sophisticated elastoplastic Models. The equations can be directly used in simple spreadsheet functions or real-time data processing schemes to make faster and more efficient decision.
B.w. Stump - One of the best experts on this subject based on the ideXlab platform.
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Quantification and characterization of regional seismic signals from cast blasting in mines: A Linear Elastic Model
Geophysical Journal International, 1997Co-Authors: Sridhar Anandakrishnan, Steven R. Taylor, B.w. StumpAbstract:Cast blasts in coal mines, designed to move large volumes of overburden, are a source of large (1-5kt), frequent explosions in parts of the world with near-surface coal resources. Mining events of this source type are triggering the prototype International Monitoring System for the Comprehensive Test Ban Treaty being tested under the Group of Scientific Experts Technical Test 3 (GSETT-3). We wish to develop techniques to distinguish between the seismic signals produced by these explosions and equivalent size single (or point) sources. To that end, we have developed a Linear Elastic Model to simulate regional-distance seismograms from mining cast blasts. Cast blasting involves a shot-array with delayed detonations casting rock horizontally into a pit. We Model the effects of the millisecond-delay-firing pattern, the depth of the pit and the cast of material into the pit. We attempt to separate the effects due to the explosion, the vertical movement of mass and the horizontal movement of mass in order to produce a physical understanding of the resulting waveforms, which can be used to assess potential discriminants for these types of explosions. These physical Models of source processes are constrained by near-surface measurements of cast blasts in NE Wyoming that are triggering GSETT-3. Two observational results at regional distances that are replicated by these Models are the excitation of 8-12 s surface waves by the cast blasts and the insensitivity of peak amplitude to total explosive size for normal blasting practices. The insensitivity of peak amplitudes from the cast blast to total source size is a consequence of the delay-firing practice under normal procedures. This practice was initiated to reduce ground motions in the near-source region around the mine and it appears that it is also successful in controlling peak amplitudes at regional distances. The mass transfer into the pit has both a vertical and a horizontal force component, each of which contribute to the final seismogram, the latter being azimuthally dependent. Assuming maximum coupling, the contribution to the seismogram due to the vertical force component is approximately equal to the explosion contribution for pit depths of about 10 m, but dominates for pit depths of 20 m or greater. The contribution due to the horizontal force component is mainly in the enhanced Rayleigh waves. Comparison of high-frequency seismic radiation from the single shot and cast blast shows little qualitative difference in the regional waveforms.
Lin Yufei - One of the best experts on this subject based on the ideXlab platform.
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Finite element Model of bending fatigue test of aluminumalloy wheel
Journal of Engineering Design, 2011Co-Authors: Lin YufeiAbstract:In the development stage of aluminumalloy wheel,the bending fatigue test is one of the bench tests that must be passed,to which the trial casting wheel on a small batch basis was put.To avoid experiments of blindness,reduce the number of tests,cut down the experiment cost and improve the reliability,the finite element method is applied,which is one of the advanced technologies in design stage.To apply the technology correctly,the effective calculation Model must be built to simulate bench tests.Based on the theoretical analysis and practical case,considering the nonLinear contact relations from pretightening of blot and the material of difference between loading bar and wheel,three finite element Models of bending fatigue tests were built,such as integral Linear Elastic Model with loading bar and wheel in the same material,the separated Linear Elastic Model with loading bar and wheel in different material,the nonLinear Model considering with the affection of contact relations and pretightening force.According to analysis and confrontation,and verification test oriented with the typical wheel,theirs advantages and shortages,stress range and computing reliability were studied;the veracity of Models was verified with the test of a typical wheel.The research shows the nonLinear load Model is corrected,the Linear Elastic Model can be used to analyze the fatigue of wheel which is easy to be broken near bolt hole,and the samedifferent material of loading bar and wheel is less influential on the most equivalent stress,and the nonLinear contact Model,considering with the affection of contact relations and pretightening force,was applicable to the analysis of the wheel which is easy to be broken near bolt hole.
Bo Alfredsson - One of the best experts on this subject based on the ideXlab platform.
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Non-Linear Elastic characterisation of a high strength bainitic roller bearing steel
International Journal of Mechanical Sciences, 2013Co-Authors: I. Linares Arregui, Bo AlfredssonAbstract:Abstract A small but not negligible non-Linear Elastic behaviour was detected when investigating cyclic uniaxial push–pull experiments on a high strength bainitic steel. Cyclic torsion experiments led to the conclusion that the shear modulus was relatively constant. A non-Linear Elastic Model was implemented where the bulk modulus was extended with a second order term related to the Elastic dilatation and where the shear modulus was constant. The material presented a strength differential effect (SDE), with larger yield stress in compression than in tension. Consequently, the non-Linear Elastic Model was combined with a plasticity Model that incorporated a Drucker–Prager yield surface, non-associated flow rule and combined non-Linear hardening. Expressions that include non-Linear Elasticity were derived for the Elastic–plastic hardening and the compliance tensors. The extended material Model predicted the Elastic–plastic results from cyclic push–pull experiments. Also, a phenomenological analysis of the cyclic Elastic response showed isotropic damage in the Elastic moduli. The steady-state damage increased Linearly with the cyclic plastic strain range.