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1

Trend analysis of rail corrugation in metro lines considering friction memory and interface effects

Wang Zhiqiang, Lei Zhenyu

Journal of Theoretical and Applied Mechanics

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2023

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Vol. 61 nr 2

331--342

EN

In order to investigate the evolution trend of rail corrugation under the action of slip and interface effects, stick-slip vibration characteristics of a wheel-rail system in different line con- ditions have been analyzed in detail by establishing a complete three-dimensional coupling metro vehicle-track numerical model and considering the friction memory effect characteriz- ing the slip rate and state dependence as well as interface effect. The results show that on a straight line, the friction memory effect has less influence on the wheel-rail contact stick-slip characteristics, and the values and variation ranges of adhesion coefficients and creepages are relatively small, indicating that it is difficult for the wheel-rail system to have stick-slip vibration, which makes it less likely to form rail corrugation. On a curved line, the fluctua- tion amplitudes of the inside longitudinal stick-slip characteristics and the outside transverse stick-slip characteristics are relatively large, which illustrates that the inside wheel-rail sys- tem is more prone to stick-slip vibration in the longitudinal direction, while the outside wheel-rail system is more prone to stick-slip vibration in the transverse direction, thus lead- ing to different forms of rail corrugation. The friction memory effect reduces longitudinal and transverse creepages of both the inside and outside wheel-rail systems, demonstrating that the friction memory effect can moderate the relative wheel-rail slip and thus reduce the development rate of rail corrugation. The interface effect makes longitudinal and transverse adhesion coefficients of the wheel-rail system tend to homogenize and mostly decrease, while the corresponding creepages tend to increase. Although an increase in the creepage induces an enhanced interface slip, a smaller adhesion coefficient does not cause a significant change in the corrugation evolution. Friction memory and interface effects can cause the wheel-rail contact adhesion area ratio to increase, thus making the contact stick-slip distribution tend to homogenize, which is beneficial to reduce wear in the contact area and promote wear to homogenize.

2

Finite element simulation of the normal interaction of particles in the visco-elastic solid

Rimsa V., Kacianauskas R., Sivilevicius H.

Mechanics and Control

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2011

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Vol. 30, no. 4

245-253

EN

This paper addresses the 3D FE simulation of the normal interaction of stiff but deformable particles in binder matrix on the meso-scale. The particles are assumed to be elastic spheres while matrix is considered as viscoelastic solid. The investigation is aimed to capture interaction in terms of normal forces under tension. The problem is considered by applying geometrically linear and nonlinear approaches. Results illustrate influence of initial interparticle gap reduction of which yields significant increase of the interaction force. Comparison between purely elastic and viscoelastic solutions is also presented.

PL

Niniejszy artykuł dotyczy trójwymiarowej symulacji metodą elementów skończonych oddziaływania w kierunku normalnym sztywnych, ale odkształcalnych cząstek w spoistej osnowie na poziomie mezoskopowym. Cząstki są traktowane jako sprężyste kule, zaś osnowa jako ciało lepkosprężyste. Badania mają na celu znalezienie sił oddziaływania pod obciążeniem. Zagadnienie jest rozpatrywane przy zastosowaniu modelu geometrycznie liniowego i nieliniowego. Wyniki pokazują wpływ wstępnego zmniejszenia odstępu na znaczący wzrost siły oddziaływania. Przedstawione jest również porównanie między rozwiązaniem sprężystym i lepkosprężystym.

3

Rheological behaviour of protein interfacial layers in emulsion stability

Izmailova V. N., Yampolskaya G. P.

Applied Mechanics and Engineering

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1999

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Vol. 4, no spec.

141-144

EN

Rheological properties of interface layers determine the emulsion stability against coalescence and effect mechanics and flow of emulsions. The role in emulsion stability of Rehbinder structure-mechanical barrier due to elasticity of interfacial layers formed by fine dispersed solids and liquid droplets, or adsorbed polymers, or multilayers of adsorbed surfactants of any nature is emphasized. Emulsions are systems of great importance because of their widespread application. A number of questions of emulsion properties and production was the object of many investigations over a long period of time, of which emulsion stability is the most general.