A COMPARATIVE STUDY OF PARAMETRIC MODELS OF MAGNETORHEOLOGICAL FLUID SUSPENSION DAMPERS
Magnetorheological dampers more commonly called, MR dampers, are being developed for a wide variety of applications where controllable damping is desired. MR damper is an intelligent damper, which is used as automobile suspension for vibration control. MR fluids represent a class of smart materials whose rheological properties change in response to the application of a magnetic field. MR fluid dampers are new type of vibration control elements, having the advantages of rapid damping and stiffness changing in the presence of an applied magnetic field. MR dampers have received a great deal of attention in the last two decades due to their being a potential technology to conduct semi-active control. It is therefore vitally important to understand the dynamic behavior of such devices whose nonlinear hysteresis is a rather complicated phenomenon. Models can accurately represent the behaviour of MR dampers are essential in understanding the operation and working principles of the device. Such models can eliminate a great deal of uncertainties during the design process, which can subsequently enable control strategies for the damper to be developed efficiently and reliably. In this paper, MR fluid structure, damper description and parametric models have been presented.
RESPONSE OF CAR SEAT SUSPENDED BY A MAGNETO- RHEOLOGICAL (MR) DAMPER
Ride with comfort is the most important demand in vehicle industry as it affects directly seats mounting. For that reason a lot of effort has been made to improve ride comfort by isolating vehicle from road irregularities as possible. That can be done by improving vehicle suspension ability to dampen the vibration induced from road irregularities during vehicle maneuver before it reaches the vehicle seat.This work investigates the effect of active damping on vehicle vibrations by presenting mathematical model of full active vehicle suspensions. That model introduced a new active damper tested recently and proved to be efficient. These dampers depend on kind of Magneto-Rheological fluid (MR). Also a mathematical model is derived for full vehicle its seat is suspended by a classical damper or Magneto-Rheological (MR) damper. Many types of roads are tested for vibration effect on the driver and suspension of the vehicle. These roads are of types repeated pulses, repeated trapezoid bumped, repeated half sine, repeated cosine and repeated simple harmonic. Also another three different roads are taken into consideration (half sine, ramp, and sudden step type). Computer programs are constructed which include a classical damper or MagnetoRheological (MR) damper and can be implemented on a full vehicle suspension. Also a simulation program (MATLAB-SIMULINK) from which any response to any changes in any parameter can be obtained. Time response curves for all types of roads are plotted for both classical and (MR) damper. A comparison between the types of roads as effect for seat (heave), and axle suspension was studied. Also the effect of voltage input to (MR) damper on vibration of the vehicle was investigated. Keyword: Magneto -Rheological fluid, Vehicle, Seat, Damper, Bumped, Road, Modeling,
Professional support in rural New South Wales: perceptions of new graduate occupational therapists.
OBJECTIVE
To explore the experiences of professional support among new graduates working in rural New South Wales, including the current availability of professional support and the impact of support levels on professional practice.


DESIGN
Qualitative, using semistructured face-to-face or telephone interviews.


SETTING
New graduate occupational therapists employed in public and private hospitals and community health services in rural New South Wales.


SUBJECTS
Nine new graduate occupational therapists within their first year of practice.


MAIN OUTCOME
A description of participant experiences of professional support and strategies to enhance the recruitment and retention of occupational therapists in rural areas.


RESULTS
Participants reported varied experiences of professional support and emphasised the importance of having access to a wide variety of resources. Participants highlighted that professional support could assist in developing independence and other skills. However, ultimately a lack of support resulted in decreased confidence and subsequent decreased job satisfaction among participants.


CONCLUSIONS
The findings suggest that greater effort should be directed to ensuring that all new graduates have access to professional support, including structured supervision, and that strategies be explored and adopted to ensure that this occurs.