Wyniki wyszukiwania - BazTech

1

Free Vibration Analysis of Axially Moving Viscoelastic Plate

Marynowski K.

Machine Dynamics Problems

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2009

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Vol. 33, No. 1

101-103

EN

Extended abstract Axially moving plates one can meet in industry as power transmission belts, band saw blades, paper webs during manufacturing and printing processes and also as flat objects moving with high speeds in outer space. Transport speed in some instances may cause excessive vibrations, wrinkling and even breaking in the case of moving webs. Exact dynamic analysis of these systems is very important to answer the question how to avoid these problems. The important problem one can meet in considering dynamic behaviour of axially moving two-dimensional system is how to model the plate material. In many instances the simplest elastic model is not sufficient and moving continua must be considered as viscoelastic. It makes dynamic analysis much more complicated. In the case of viscoelastic material the state of strain in an element at a particular time not only depends on the state of stress at this time, but also on the history of stresses. Similarly the state of stress of an element depends on the history of strains. This memory effect should be taken into account in dynamic investigations. Full text of the paper has been submitted to European Journal of Mechatroncs A/Solids in August' 2009.

2

Flow of a magneto-micropolar fluid with temperature dependent viscosity and thermal conductivity past a continuously moving plate

Modather M., Abdou M.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 2

461-471

EN

A boundary layer analysis has been presented to study heat transfer with the effects of temperature dependent viscosity and thermal conductivity in the laminar, viscous, incompressible, electrically conducting, micropolar fluid past a continuously moving plate in the presence of a transverse magnetic field. The governing equations are transformed to dimensionless similarity boundary layer equations. Numerical solutions are given for the governing momentum, angular momentum and energy equations using the shooting method. The effects of the magnetic field parameter, the viscosity variation parameter, thermal conductivity variation parameter and micropolar parameter on the skin friction, wall couple stress and rate of heat transfer are discussed.

3

Dynamic behaviour of an axially moving thin orthotropic plate

Marynowski K., Kołakowski Z.

Journal of Theoretical and Applied Mechanics

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1999

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nr 1

109-128

EN

A new approach to analysis of the dynamic behaviour of axially moving orthopedic plates is presented. The nonlinear orthotropic plate theory is modified to include the inertial forces resulting from the moving web.The results of numerical investigations show the solution to a linear problem. The effects of the ortotropy factor, axial transport velocity and rolls support system on transverse and torsional natural frequencies and stability of the plate motion are presented. The lowest natural frequencies decrease with the increasing axial velocity at undercritical transport speeds. The plate may experience divergent or flutter instability at supercritical transport speeds. A second stable region above the critical speed may exist as well.

PL

W pracy przedstawiono nową metodę analizy dynamicznej poruszających się osiowo płyt ortotropowych. Wyniki obliczeń numerycznych pokazują rozwiązanie problemu liniowego. Badano wpływ współczynnika ortotropii, prędkości osiowej oraz sztywności podparcia rolek na poprzeczne i skrętne częstości drgań własnych i stateczność ruchu płyty. Wartości najniższych częstości własnych zmniejszają się wraz ze wzrostem prędkości w podkrytycznym zakresie prędkości przesuwu. W zakresie nadkrytycznym może występować niestateczność dywergencyjna lub typu flater. W zakresie nadkrytycznym może się również pojawić drugi obszar stateczności ruchu.

4

Micropolar fluid flow past a continuously moving plate in the presence of magnetic field

Mansour M. A., Gorla R. S. R.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 4

663-672

EN

A similarity analysis of the flow and heat transfer with magnetic field past a continuously moving semi-infinite permeable plate in a micropolar fluid is presented. The velocity, micro-rotation distribution, the temperature profiles, the skin friction and the rate of heat transfer are shown on graphs. Also the numerical values of the skin friction and the rate heat transfer are entered in tabular form.