W pracy przedstawiono nową metodę numerycznego całkowania równań ruchu z lepko-sprężystymi tłumikami drgań. Tłumiki drgań są opisywane za pomocą ułamkowego modelu Maxwella. Do opisu tego modelu stosuje się pochodne ułamkowe (niecałkowitego rzędu). Podano podstawy teoretyczne proponowanej metody oraz omówiono wyniki przykładowych obliczeń.
EN
The new numerical method of integration of equation of motion of structural systems with viscoelastic dampers is presented in the paper. Viscoelastic dampers are described with a help of the fractional rheological model of Maxwell type. The fractional derivatives are use in description of dampers. The theoretical basis of the proposed method are presented. Moreover, results of exemplary calculation are described and briefly discussed.
A field study was done to evaluate different seat designs in the aspect of minimizing vibration transmission and reducing the level of discomfort experienced by drivers subjected to transient vibration. Two seat designs (sliding or fixed in the horizontal direction) were compared in an experimental based on variation of sitting posture, speed, and type of obstacle. The comparison was done by assessing discomfort and perceived motion and by vibration measurement. Ten professional drivers were used as participants. Maximum Transient Vibration Value and Vibration Dose Value were used in the evaluation. The results showed that a sliding seat is superior in attenuating vibration containing transient vibration in the horizontal direction. It was also perceived as giving less overall and low back discomfort compared to a fixed seat.
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A problem if unsteady linear closed loop system vibration is formulated and solved in this paper. Proportional, ideal derivative and delayed feedback interaction is considered. The mixed method of rigid and deformable finite elements is extended by including coupling elements, and applied to modelling the system. An unconditionally stable numerical integration variant of the Newmark method is used for solving the problem. Special computer software is implemented and illustrative calculation of the traverse shaper's model are performed. Time and frequency plots for chosen generalised coordinates of the model and for several cases of the feedback interaction, are obtained as results.
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