How to Size a Shock Absorber for Vertical Motion
Add gravity work when the load moves downward into the absorber and subtract it when gravity opposes the stop.
Direct answer
Vertical sizing starts with kinetic energy, then adjusts for gravity over the stopping stroke. Gravity assists downward impacts and increases the energy to absorb; gravity opposes upward motion and can reduce the absorbed energy requirement.
Questions this page answers
- How do I size a shock absorber for vertical motion?
- How does gravity affect shock absorber calculation?
- How do I calculate a shock absorber for a vertical falling load?
Required inputs
Formula logic
Gravity work over stroke
m is mass in kg, g is 9.80665 m/s2 and s is stopping stroke in meters.
Wg = m x g x sUnit: N m
Calculation steps
- 1
Calculate kinetic energy
Use the impact velocity at the moment the load reaches the absorber.
- 2
Adjust for gravity
Add gravity work for downward motion and subtract it for upward motion where gravity opposes the impact.
- 3
Check rating and safety margin
Compare energy, force, stroke and duty cycle against the selected product family.
Common mistakes
- Treating vertical and horizontal cases as identical.
- Forgetting gravity work on downward moving masses.
- Not checking return force and reset behavior for vertical equipment.
Catalog source notes
- The full product catalog p.39 and p.50 require the user to specify vertical or horizontal motion for heavy-duty absorber application data.
Move from answer to model shortlist.
Use the sizing tool when you have the inputs, or send the application data for engineering review.