The compliance contact model of cylindrical joints with clearances

This paper is concerned with the determination of the normal force-displacement (NFD) relation for the contact problem of cylindrical joints with clearance. A simple formulation for this contact problem is developed by modeling the pin as a rigid wedge and the elastic plate as a simple Winkler elastic foundation. The numerical results show that the normal displacement relation based on Hertz theory is only valid for the case of large clearance with a small normal load, and the NFD relation based on Persson theory is only effective in the case of very small clearance. The proposed approximate model in this paper gives better results than Hertz theory and Persson theory in a large range of clearances as seen from the comparison with the results of FEM. The project supported by the National Natural Science Foundation of (10272002; 60334030). The English text was polished by Keren Wang.     

Thermal contact conductance for cylindrical and spherical contacts

A prediction methodology based on Monte-Carlo simulation model, developed for flat conforming surfaces in contact, is modified and extended to predict contact conductance between curvilinear surfaces like cylinders and spheres. Experiments are also conducted in vacuum for the measurement of contact conductance between stainless steel and aluminium cylindrical contacts and stainless steel spherical contacts over a range of contact pressures. The contact conductance between cylindrical and spherical bodies is, in general, about an order of magnitude lower than for flat surfaces in contact. Increase of surface roughness and decrease in contact pressure lowers the contact conductance. However, the influence of these parameters is larger than those obtained for flat surfaces. The prediction for different parametric conditions agree closely with those measured in the experiments.     

Nonlinear vibrations of cantilevered circular cylindrical shells in contact with quiescent fluid

Large-amplitude vibrations of liquid-filled cantilevered (clamped–free) circular cylindrical tanks are studied theoretically for the first time. The influence of liquid height and initial geometric imperfections is investigated in detail. The tank motions are described by a nonlinear model based on Flügge׳s shell theory, and the liquid motions are modelled by means of linearized potential flow theory. Equations of motion are obtained using the extended Hamilton׳s principle and are discretized by expanding the solution with trigonometric functions in the circumferential direction and the cantilevered beam eigenfunctions in the axial direction. The geometric boundary conditions are satisfied exactly, while the natural ones are satisfied in an energy minimization sense. The system is integrated numerically by employing the appropriate modal composition of the solution to guarantee convergence. Results are presented in the form of frequency–response curves in the neighbourhood of the lowest natural frequency. It is found that the response may be of softening or hardening type, depending on the liquid height and the imperfection parameters.     

Nonstationary plane contact problem in theory of elasticity for conformal cylindrical surfaces

A numerical–analytical approach is described to investigate the process of impact interaction between a long smooth rigid body and the surface of a circular cylindrical cavity in elastic space. A non-stationary mixed initial boundary value problem is formulated with a priori unknown boundaries moving with variable velocity. The problem is solved using the methods of the theory of integral transforms, expansion of desired variables into a Fourier series, and the quadrature method to reduce the problem to solving a system of linear algebraic equations at each time step. Some concrete numerical computations are presented.The cylindrical body mass and radius impact on the proile of the transient process of contact interaction has been analysed.     

Determination of surface heat transfer coefficients from measured temperature data for spherical and cylindrical bodies during cooling

In this paper which is a combination of the methodological and experimental aspects, models were developed for determining surface heat transfer coefficients for spherical and cylindrical bodies from their center temperature measurements during forced-cooling. Experiments involved the cooling of the individual spherical and cylindrical products as test samples in the air flow. The cooling parameters in terms of the cooling coefficients and lag factors were also determined to use in the present models. The results show that the surface heat transfer coefficients of the individual spherical and cylindrical products increased with an increase in the flow velocities from 1 to 2 m/s. It can be concluded that the present models have the capabilities of determining the surface heat transfer coefficients for spherical and cylindrical bodies with a single transient experiment.     

Experimental investigation of vibrations of a cylindrical shell in contact with a liquid

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 27, No. 5, pp. 63–68, May, 1991.     

Axisymmetric oscillations of a cylindrical droplet with a moving contact line

Forced oscillations of a cylindrical droplet of an inviscid liquid surrounded by another liquid and bounded in the axial direction by rigid planes are investigated. The system is affected by vibrations whose force is directed parallel to the axis of symmetry of the droplet. The velocity of motion of the contact line is proportional to the deviation of the contact angle from the value at which the droplet is in equilibrium. Linear and nonlinear oscillations are considered. The conditions of the occurrence of resonance are determined.