Analytical and Numerical Approach of Dynamic Behaviour of Flexible Metal Mesh Structures

2015 ◽  
pp. 233-237
Author(s):  
E. Wilhelm ◽  
J. Wellnitz
Keyword(s):  
Dynamic Behaviour ◽  
Numerical Approach ◽  
Metal Mesh ◽  
Flexible Metal ◽  
Mesh Structures

Experimental and Numerical Approach to Study Dynamic Behaviour of Pavement under Impact Loading

2009 ◽  
pp. 755-760
Author(s):  
Cherif Asli ◽  
Zhiqiang Feng ◽  
Gérard Porcher ◽  
Jean Jacques Rincent
Keyword(s):  
Impact Loading ◽  
Dynamic Behaviour ◽  
Numerical Approach

Effects of Mesh Density on Static Load Performance of Metal Mesh Gas Foil Bearings

2011 ◽  
Author(s):  
Yong-Bok Lee ◽  
Chang Ho Kim ◽  
Tae Ho Kim ◽  
Tae Young Kim
Keyword(s):  
Test Data ◽  
Loss Factor ◽  
Static Load ◽  
Stiffness Coefficient ◽  
Metal Mesh ◽  
Rotor Spinning ◽  
Foil Bearings ◽  
Mesh Density ◽  
Damping Loss Factor ◽  
Mesh Structures

Metal mesh materials have been used successfully in vibration isolators and bearing dampers due to their superior friction or hysteresis damping mechanism. These materials are formed to metal mesh (or wire mesh) structures in ring-shape by compressing a weave of metal wires, in general. Recently, oil-free rotating machinery implement metal mesh structures into hydrodynamic gas foil bearings by replacing bump strip layers with them, to increase its bearing structural damping. A metal mesh foil bearing (MMFB) consists of a top foil and support elastic metal mesh pads installed between a rotating shaft and a housing. The present research presents load capacity tests of a MMFB at rotor rest (0 rpm) and 30 krpm for three metal mesh densities of 13.1%, 23.2%, and 31.6%. The metal mesh pad of test MMFB is made using a stainless steel wire with a diameter of 0.15 mm. Test rig comprises a rigid rotor with a diameter of 60 mm supported on two ball bearings at both ends and test MMFB with an axial length of 50 mm floats on the rotor. Static loads is provided with a mechanical loading device on test MMFB and a strain gauge type load cell measures the applied static loads. A series of static load versus deflection tests were conducted for selected metal mesh densities at rest (0 rpm). Test data are compared to further test results of static load versus journal eccentricity recorded at the rotor speed of 30 krpm. Test data show a strong nonlinearity of bearing deflection (journal eccentricity) with static load, independent of rotor spinning. Observed hysteresis loops imply significant structural damping of test MMFB. Measured journal deflections at 0 rpm are in similar trend to recorded journal eccentricities at the finite rotor speed, thus implying that the MMFB performance depends mainly on the metal mesh structures. The paper also estimates linearlized stiffness coefficient and damping loss factor of test MMFB using the measured static load versus deflection test data at 0 rpm and 30 krpm. The results show that the highest mesh density of 31.6% produces highest linearlized stiffness coefficient and damping loss factor. With rotor spinning at 30 krpm, the linearlized stiffness coefficient and damping loss factor decrease slightly, independent of metal mesh densities. The present test data will serve as a database for benchmarking MMFB predictive models.

scholarly journals Modified stepped scheme for modelling the dynamic behaviour of 3D poroviscoelastic solids

2018 ◽  
Vol 174 ◽  
pp. 02019
Author(s):  
Leonid Igumnov ◽  
Aleksandr Ipatov ◽  
Svetlana Litvinchuk
Keyword(s):  
Dynamic Behaviour ◽  
Boundary Integral Equations ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Boundary Integral ◽  
Dynamic Responses ◽  
Elastic Model ◽  
Weakly Singular Kernel ◽  
Soil Medium

The problem of the dynamic response of a soil medium under different kinds of loads is of significant importance in various areas of engineering, especially in connection with structures. The present paper is dedicated to the modification of the numerical approach for modelling the dynamic behaviour of three dimensional poroviscoelastic solids. The basic equations for fluid-saturated porous media proposed by Biot are modified by replacing the classical linear elastic model of the solid skeleton with the viscoelastic model. Classical models of viscoelasticity are employed, such as Kelvin-Voight model, standard linear solid model and model with weakly singular kernel. Boundary integral equations method is applied to solving three-dimensional boundary-value problems. Stepped schemes modifications based on the linear and quadratic approximation of function are employed. A numerical example of poroviscoelastic rod under Heaviside type load is provided. A problem of a poroviscoelastic cube with a cavity subjected to a normal internal pressure is considered. The comparison of dynamic responses when poroviscoelastic material is described by different viscoelastic models is presented.

scholarly journals Numerical Approach of a Water Flow in an Unsaturated Porous Medium by Coupling Between the Navier–Stokes and Darcy–Forchheimer Equations

2017 ◽  
Vol 54 (6) ◽  
pp. 54-64
Author(s):  
K. Hami ◽  
I. Zeroual
Keyword(s):  
Unsaturated Zone ◽  
Dynamic Behaviour ◽  
Stokes Equations ◽  
Numerical Approach ◽  
Underground Water ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Conservation Of Momentum ◽  
Basic Equations ◽  
The Impact

AbstractIn the present research, simulations have been conducted to determine numerically the dynamic behaviour of the flow of underground water fed by a river. The basic equations governing the problem studied are those of Navier–Stokes equations of conservation of momentum (flows between pores), coupled by the Darcy–Forchheimer equations (flows within these pores). To understand the phenomena involved, we first study the impact of flow rate on the pressure and the filtration velocity in the underground medium, the second part is devoted to the calculation of the elevation effect of the river water on the flow behaviour in the saturated and unsaturated zone of the aquifer.

Special indications for endoscopic use of flexible metal mesh stents

1998 ◽  
Vol 114 ◽  
pp. A603
Author(s):  
K.E. Grund ◽  
D. Schaefer ◽  
D. Stueker ◽  
U. Schrimpf
Keyword(s):  
Metal Mesh ◽  
Flexible Metal

Effects of Mesh Density on Static Load Performance of Metal Mesh Gas Foil Bearings

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Yong-Bok Lee ◽  
Chang Ho Kim ◽  
Tae Ho Kim ◽  
Tae Young Kim
Keyword(s):  
Test Data ◽  
Loss Factor ◽  
Static Load ◽  
Stiffness Coefficient ◽  
Metal Mesh ◽  
Rotor Spinning ◽  
Foil Bearings ◽  
Mesh Density ◽  
Damping Loss Factor ◽  
Mesh Structures

Metal mesh materials have been used successfully in vibration isolators and bearing dampers due to their superior friction or hysteresis damping mechanism. These materials are formed to metal mesh (or wire mesh) structures in ring-shape by compressing a weave of metal wires, in general. Recently, oil-free rotating machinery implement metal mesh structures into hydrodynamic gas foil bearings by replacing bump strip layers with them, to increase its bearing structural damping. A metal mesh foil bearing (MMFB) consists of a top foil and support elastic metal mesh pads installed between a rotating shaft and a housing. The present research presents load capacity tests of a MMFB at rotor rest (0 rpm) and 30 krpm for three metal mesh densities of 13.1%, 23.2%, and 31.6%. The metal mesh pad of test MMFB is made using a stainless steel wire with a diameter of 0.15 mm. Test rig comprises a rigid rotor with a diameter of 60 mm supported on two ball bearings at both ends and test MMFB with an axial length of 50 mm floats on the rotor. Static loads is provided with a mechanical loading device on test MMFB and a strain gauge type load cell measures the applied static loads. A series of static load versus deflection tests were conducted for selected metal mesh densities at rest (0 rpm). Test data are compared to further test results of static load versus journal eccentricity recorded at the rotor speed of 30 krpm. Test data show a strong nonlinearity of bearing deflection (journal eccentricity) with static load, independent of rotor spinning. Observed hysteresis loops imply significant structural damping of test MMFB. Measured journal deflections at 0 rpm are in similar trend to recorded journal eccentricities at the finite rotor speed; thus implying that the MMFB performance depends mainly on the metal mesh structures. The paper also estimates linearlized stiffness coefficient and damping loss factor of test MMFB using the measured static load versus deflection test data at 0 rpm and 30 krpm. The results show that the highest mesh density of 31.6% produces highest linearlized stiffness coefficient and damping loss factor. With rotor spinning at 30 krpm, the linearlized stiffness coefficient and damping loss factor decrease slightly, independent of metal mesh densities. The present test data will serve as a database for benchmarking MMFB predictive models.

scholarly journals Dynamic behaviour of Various Fibre Systems During Impact Interaction – Numerical Approach

2015 ◽  
Vol 23 (6(114)) ◽  
pp. 72-82 ◽  
Author(s):  
Paweł Baranowski ◽  
Jerzy Małachowski ◽  
Tadeusz Niezgoda ◽  
Łukasz Mazurkewicz
Keyword(s):  
Dynamic Behaviour ◽  
Numerical Approach ◽  
Impact Interaction
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