08-16-2017, 10:58 PM
Evaluation of Active Damping for Reduction of Noise, Vibration and
Motion of Ground Vehicles
The off-road vehicles are subject to large vibrations which can have severe affects on drivers, crew and load.Most ground vehicles are equipped with passive spring and damping devices which have reached a high
level of sophistication.active damping, has reached production stage for luxury vehicles, trucks and trains.
Studies by Karnopp [8] for automotive applications suggest that the efficiency of semi-active dampers is only marginally lower than of a fully active system. Active dampers based on several mechanical principles are available on the market.
Semi-active Suspensions
semi-active devices are typically represented by (controllable) semi-active dampers (SAD),which are able to alternate damping ratio by means of a controllable orifice, according to an input signal.Thus, the semi-active control is also known as
active damping and the output signal is electrical in nature.
if the control signal is
disconnected, the shock absorber behaves as a purely passive damper.
ACTUATION HARDWARE
Semi-active actuators:
A complete active or semi-active suspension can consist of an arrangement of passive and active components.The semi-active dampers can
be manufactured based on controllable orifice, or controllable fluids technology.
Passive shock absorbers:
fluid in the shock absorber is forced to flow through restricted outlets and
valve systems (orifice), thus generating hydraulic resistance and thus producing damping.
Dampers with Controllable Orifice:
modified passive hydraulic (or gas) dampers
extended with a solenoid valve with a variable orifice are the ones usually used in this type.
Magnetorheological dampers:
materials which respond to an applied magnetic field with a change
in rheological properties like elasticity, plasticity, or viscosity are called Magnetorheological fluids. they include polarizable particles of a micron size.MR Fluid is a free-flowing liquid in normal conditions but application of a magnetic can transform the fluid into a near-solid in milliseconds.
for full report, refer this pdf:
http://dtic.mil/cgi-bin/GetTRDoc?AD=ADA4...tTRDoc.pdf
Motion of Ground Vehicles
The off-road vehicles are subject to large vibrations which can have severe affects on drivers, crew and load.Most ground vehicles are equipped with passive spring and damping devices which have reached a high
level of sophistication.active damping, has reached production stage for luxury vehicles, trucks and trains.
Studies by Karnopp [8] for automotive applications suggest that the efficiency of semi-active dampers is only marginally lower than of a fully active system. Active dampers based on several mechanical principles are available on the market.
Semi-active Suspensions
semi-active devices are typically represented by (controllable) semi-active dampers (SAD),which are able to alternate damping ratio by means of a controllable orifice, according to an input signal.Thus, the semi-active control is also known as
active damping and the output signal is electrical in nature.
if the control signal is
disconnected, the shock absorber behaves as a purely passive damper.
ACTUATION HARDWARE
Semi-active actuators:
A complete active or semi-active suspension can consist of an arrangement of passive and active components.The semi-active dampers can
be manufactured based on controllable orifice, or controllable fluids technology.
Passive shock absorbers:
fluid in the shock absorber is forced to flow through restricted outlets and
valve systems (orifice), thus generating hydraulic resistance and thus producing damping.
Dampers with Controllable Orifice:
modified passive hydraulic (or gas) dampers
extended with a solenoid valve with a variable orifice are the ones usually used in this type.
Magnetorheological dampers:
materials which respond to an applied magnetic field with a change
in rheological properties like elasticity, plasticity, or viscosity are called Magnetorheological fluids. they include polarizable particles of a micron size.MR Fluid is a free-flowing liquid in normal conditions but application of a magnetic can transform the fluid into a near-solid in milliseconds.
for full report, refer this pdf:
http://dtic.mil/cgi-bin/GetTRDoc?AD=ADA4...tTRDoc.pdf