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Vibration Transmitted to the Human Body during the Patient’s Ride in a Wheelchair

100%

Dziechciowski Z. S. , Kromka-Szydek M.

tom Vol. 42, No. 1

137--148

The study investigates the spectra of vibrations transmitted onto the body of a wheelchair user during the ride on typical floor surfaces in public buildings and in their vicinity. Three wheelchair types are considered in the study (universal and active ones). Selected factors are examined that determine the amplitude of vibration acceleration acting upon humans in the analysed frequency range (wheelchair type, user’s body mass, surface type). The spectral analysis gives an insight into some of the factors which lead to a change of the vibration parameters registered at the user’s seat.

Modelirovanie i avtomatizirovannyj rascet dinamiki rotornyh sistem s gibridnymi podsipnikami-uplotneniami

75%

Savin L. , Solomin O. , Ustinov D.

2008

tom Z. 10, Vol. 1

35-42

This article deals with modeling of dynamic behavior in rotor system, including horizontal rigid rotor, rotating with constant angular velocity in two hybrid fluid-film bearing. This bearing is a combination of smooth and multilobe supporting surfaces, that allows to treat it as contactless supporting- sealing unit. The article contains result analysis of computing experiments, received with the help of special developed software.

The effect of liquid temperature and viscosity on the amplitude-frequency characteristics of a viscotic torsion damper

75%

Homik W.

Polish Maritime Research

2012

tom nr 4

71--77

The article discusses causes of the appearance of transverse, longitudinal and torsional crankshaft vibrations in multi-cylinder internal combustion engines. Particular attention is paid to the torsional vibration which is the most severe threat to engine crankshafts. Damping methods making use of torsion dampers are presented. With the reference to viscotic dampers, problems with their damping efficiency are discussed in the context of viscosity changes of the damping liquid. The article also presents the amplitude-frequency characteristics of a series of viscotic dampers, which were recorded experimentally on the research rig and on a real object. An idea of vibration damper metric is given.

Mathematical model and method of determination of amplitude-frequency characteristics of corrugated cylindrical shells for geometrically nonlinear vibrations

63%

Marchuk M. , Goriachko T. , Kindratskyy B. , Pakosh V.

tom Vol. 31, nr 3

art. no. 2020316

On the basis of spatial geometrically nonlinear theory of elasticity by using quadratic approximations for components of the vector of displacements along the normal coordinate to the median surface is developed a new mathematical model of nonlinear dynamics of cylindrical shells with corrugated configuration for median surface. The perturbation method for the solution of systems of nonlinear differential equations for problems of determination of amplitude-frequency characteristics is generalized. In a combination of finite element and generalized perturbations methods, a new methodology for solving problems of free geometrically nonlinear vibrations of shells with complex guide geometry was developed and verified. With its help the influence of geometrical parameters of corrugating at circular coordinate on the main frequency of the elongated cylindrical panel is investigated.

Uszkodzenia w obiektach budowlanych w warunkach wstrząsów górniczych

51%

Tatara T. , Pachla F.

Przegląd Górniczy

2012

tom T. 68, nr 7

1--10

W pracy przeanalizowano występowanie uszkodzeń w budynkach mieszkalnych na skutek działania wstrząsów górniczych o dużej intensywności. Analizom poddano wstrząsy o energiach En > E6 J z obszaru Górnośląskiego Zagłębia Węglowego (GZW), Legnicko-Głogowskiego Okręgu Miedziowego (LGOM). Uwzględniono także wstrząsy tzw. regionalne z obszaru GZW. Wyznaczono charakterystyki przebiegów drgań powierzchniowych od wstrząsów górniczych wykorzystywane w przybliżonych ocenach ich wpływu na zabudowę powierzchniową. W analizach wykorzystano Górnicze Skale Intensywności GSI i Skale Wpływów Dynamicznych SWD opracowane odpowiednio w Głównym Instytucie Górnictwa i w Instytucie Mechaniki Budowli Politechniki Krakowskiej. Wyniki analiz przybliżonych ocen wpływu drgań powierzchniowych pochodzenia górniczego na budynki porównano ze stwierdzonymi i udokumentowanymi uszkodzeniami w budynkach. Analizy te były pomocne w udzieleniu odpowiedzi na pytanie dotyczące szkodliwości wpływu wstrząsów o analizowanej intensywności na konstrukcje budynków.

The study analyzes the occurrence of damages in apartment buildings as a result of mining tremors of high intensity. To analyses were subjected tremors with energies En > E6 J from the area of the Upper Silesian Coal Basin (USCB) and Legnica-Głogów Copper Region (LGCR). Moreover, the so-called regional tremors from the USCB area were taken into consideration. The characteristics of courses of surface vibrations from mining tremors used in approximate assessments of their influence on buildings on the surface were determined. In the analyses were used Mining Intensity Scales (GSI) and Dynamic Influence Scales (SWD, worked out at the Central Mining Institute and at the Institute of Structure Mechanics of the Cracow University of Technology, respectively. The results of analyses of approximate assessments of the influence of surface vibrations of mining origin on buildings were compared with the ascertained and documented damages in buildings. The analyses were helpful in answering the question concerning the harmfulness of influence of tremors with the analyzed intensity on the constructions of buildings.