KEVOS® MAKEOS · Strength
Beam Drop Impact Check (I-Section Properties, Impact Factor, Dynamic Stress)
If a load drops onto this I-beam, what impact factor, dynamic stress and deflection result, and is the section strong enough?
Check of a fabricated or rolled I-section beam struck by a falling load: area, mass per metre, second moment and section modulus of the I-section from its flange and web sizes (as the section properties tool), then the static deflection and stress, the impact factor from the drop height and the dynamic stress and deflection for a simply supported or cantilever beam (as the impact load on a beam tool), against your allowable stress and deflection limit.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Section (I or H) | ||
| Overall depth | mm | Overall depth of the I-section. |
| Flange width | mm | Width of the flanges. |
| Flange thickness | mm | Thickness of each flange. |
| Web thickness | mm | Thickness of the web. |
| Density | kg/m³ | Density of the beam material. |
| Impact | ||
| Support | choice | How the beam is supported and where the load strikes. |
| Falling mass | kg | Mass of the falling object. |
| Drop height above the beam | mm | Height the object falls before it touches the beam. |
| Span (or cantilever length) | mm | Span between supports, or the cantilever length. |
| Elastic modulus | GPa | Elastic modulus. |
| Allowable stress | MPa | Allowable stress for the impact case (often close to yield for an accidental drop). |
| Largest dynamic deflection | mm | Largest deflection you accept during the impact. |
Method and formulas
- I-section built from two flanges and a web: area, I_x, and c = depth ÷ 2 (as the section properties tool).
- Static deflection δ_st = W L³ ÷ 48EI (simply supported) or ÷ 3EI (cantilever); impact factor = 1 + √(1 + 2h ÷ δ_st) (as the impact load on a beam tool).
- Dynamic stress and deflection = factor × static values.
- Example: I = 20.983 × 10⁶ mm⁴; the impact factor is 161.24, giving 75.358 MPa and 1.256 mm.
Limitations
- Energy method ignoring the beam’s own mass, which lowers the impact factor for heavy beams.
- Local crushing under the impact point and flange buckling are not checked.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a beam under a hoist for an accidental drop
- Check a guard or stop beam for a falling part
- Compare beam sections for impact
Who it is for
- Design engineers
- Safety engineers
- Structural designers
What you get
- Section properties
- Static and dynamic deflection
- Impact factor and dynamic stress
Interpreting the result
- A stiffer beam has a smaller static deflection and so a larger impact factor: impact resistance comes from energy absorption, not stiffness alone.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 278, 234–246. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Beam Drop Impact Check (I-Section Properties, Impact Factor, Dynamic Stress) calculator
