World leaders in the field of shock & vibration with over 60 years of industry experience.
A shock absorber is a device which converts mechanical energy into thermal energy. The energy transformation occurs as the shock absorber’s fluid medium is forced through orifices at high velocities.
Selecting a shock absorber is not difficult if you follow the equations in this guide. To insure adequate sizing, all inputs to the shock absorber must be known or conservatively estimated. For dimensions and capacity of shock absorbers click here for the “specifications” of each product.
The end goal of the equations listed in this guide is to obtain the energy input to the shock absorber, and the speed at which it occurs. If you have any questions, contact our factory for prompt assistance. An improperly sized shock absorber can be a safety hazard.
(USE ONLY THE UNITS LISTED BELOW IN ALL EQUATIONS IN THIS GUIDE.)
KE = Kinetic energy (in-lb.)
W = Weight (lb.)
WE = Effective impact weight (lb.)
V = Linear velocity of impact at the shock absorber (ft/sec.)
VR = Rotational velocity of impact (radians/sec.) at the shock absorber
F = Output force from shock absorber at impact (lb.)
FD = Drive force (lb.)
H = Vertical height (in.)
S = Shock absorber stroke (in.)
I = Moment of inertia (lb-ft-sec.2)
T = Time (sec.)
a = Acceleration (ft/sec.2)
V = 2 [Average Cylinder Velocity (ft/sec.)]
B. Hydraulic Cylinder DriveV = 1.5 [Average Cylinder Velocity (ft/sec.)]
C. Machines With Constant Acceleration And Known TimeV = aT
D. Machines With An Initial Velocity (VO, Ft/Sec.) Plus Constant Acceleration And Known TimeV = VO + aT
E. Machines With A Constant Acceleration And Known Distance (Ft.)To Gain Speed V2 = 2 (a) (distance)
A. A.C. Motors
B. D.C. Motors
** NOTE: Both A. and B. neglect gearing power losses and slippage power losses.
FD = .004 (square feet sail area) (wind speed in mph.)2
For most industrial applications, decelerations of under 8.0 g are recommended to prevent damage to electronics and to keep impact noise down. For lower decelerations, use a longer stroke unit.