PERFORMANCE TEST OF A SHOCK ABSORBER
To study the characteristics of a shock absorber.
APPARATUS REQUIRED :
Shock absorber test rig
OBJECTS OF THE SUSPENSION ARE :
- To prevent road shocks from being transmitted to the vehicle components.
- To safeguard the occupants from road shocks.
- To preserve the stability of the vehicle in pitching or rolling in motion.
MAIN FUNCTIONS OF SHOCK ABSORBERS :
- To control quick bouncing of wheels on road surface.
- To control slow bouncing of the body on the suspension springs.
DESIGN CALCULATION :
- Diameter of the piston (dp)
Piston of diameter, dp = mm.
- Diameter of the rod (dr)
The diameter of the rod, dr = 0.4 * dp
- Outer diameter of shock absorber (D) (Dust cover)
Diameter (D) = mm.
- Determination of design compression force (Fc)
Compression force, Fc = [Ap – Ar]* Pc
= π/4[dp2 – dr2]*Pc
Ap- Area of piston in m2
Ar- Area of rod in m2
Pc- Pressure transmitted through shock absorber during compression in N/m2 (0.05 to 0.25 MPa)
- Determination of design rebound force (Fr)
rebound force, Fr = Ap* Pr
Pr - Pressure transmitted through shock absorber during rebound in N/m2 (0.5 to 1 MPa)
Determination of damping coefficient:
Kc = N-s/m
µ- Flow co – efficient
υ- Density of fluid in (9000) N/m3
Thus the characteristic of a shock absorber has been studied.