Mechanics
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ISSN 1734-8927
e-ISSN: 2300-7060
Issue Date
2009
Volume
Vol. 28
Number
No. 2
Description
Journal Volume
Mechanics
Vol. 28 (2009)
Projects
Pages
Articles
Optimal hand-arm system of vibration isolation including human sensitivity to vibration
(Wydawnictwa AGH, 2009) Książek, Marek A.
In the paper the optimal vibration isolation systems (OVIS) have been analytically obtained for a new hand-arm models (HAS) subjected to stochastic excitations. The models are described by its impedance, weighted by standard frequency domain curve Wh(s) depicting hand-arm discomfort level. The analytical functions depicting OVIS have been carried out in the general form for random stationary acceleration excitations, general forms of impedance Z(s) of hand-arm system and selected criterion of isolation.
Calibration of the strip yield model for fatigue crack growth predictions in structural steel
(Wydawnictwa AGH, 2009) Machniewicz, Tomasz
The paper is focused on the calibration of the strip yield (Dugdale) model for crack growth predictions for structural steel. This is achieved by imposing appropriate constraints on yielding the strip elements. To avoid a fortuitous, i.e. physically unjustified choice of the constraint factors, a novel concept for their selection is proposed, namely matching the experimentally observed and predicted by the model cyclic stress-strain behaviour at the crack tip. The approach is shown to yield satisfactory prediction results on crack growth under constant amplitude loading and after application of an overload cycle.
Modelling of matrix degradation in piezocomposite actuators using graded material approximation
(Wydawnictwa AGH, 2009) Pietrzakowski, Marek
The work deals with modelling of material degradation in piezoelectric fiber composite (PFC) layers, which operate as actuators in active laminated plates. The considered degradation process concerns reduction of the matrix material stiffness and is described based on the functionally graded material approach. It is assumed that distribution of the matrix damage, which develops at the outer surface of the actuator layer and progresses toward its inner part, can be approximated according to a power function. The dynamic analysis and calculations are focused on changes in the natural frequencies and amplitude-frequency characteristics of the active laminated plate depending on the degradation level.
Design of volume displacement sensor
(Wydawnictwa AGH, 2009) Pietrzko, Stanisław; Mao, Qibo
This paper presents a new methodology for designing volume displacement sensors using shaped PVDF film on the basis of integration by parts. The design method proposed here does not require knowledge of the structural mode shapes. Through the design of the shape of the PVDF film, the charge output of PVDF sensor is proportional to the volume displacement of the beam. As shown the PVDF sensor shape is independent of the excitation (the type, position and frequency, etc.). Furthermore, the PVDF sensor proposed, is not sensitive to changes in the boundary conditions.
Semi-active suspension system with an MR rotary damper
(Wydawnictwa AGH, 2009) Rosół, Maciej; Gorczyca, Przemysław
The paper is concerned with a laboratory semi-active suspension system (SAS), built to demonstrate and test a number of control algorithms. The heart of the system is the automotive engineering magnetorheological (MR) rotary damper used as an actuator. The MR rotary damper enables to control the SAS damping torque in a continuous way. A designed on-off controller automatically adjusts the damping coefficient to generate the torque required to reduce the amount of energy transmitted from the source of vibrations to the suspended equipment. The experimental results of laboratory investigations of the designed control algorithm in respect to the RD-2087-01 damper have been presented.