KEVOS® MAKEOS · Fasteners
Eccentrically Loaded Bolt Group
Which bolt in this group carries the most shear when the load is offset?
Shear force on each bolt of a group of up to six under an in-plane load applied away from the group centroid, by the elastic (vector) method, against the bolt shear capacity.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Number of bolts | bolts | How many of the listed bolts are used (the first n). |
| Bolt 1 | ||
| X | mm | X position of bolt 1. |
| Y | mm | Y position of bolt 1. |
| Bolt 2 | ||
| X | mm | X of bolt 2. |
| Y | mm | Y of bolt 2. |
| Bolt 3 | ||
| X | mm | X of bolt 3. |
| Y | mm | Y of bolt 3. |
| Bolt 4 | ||
| X | mm | X of bolt 4. |
| Y | mm | Y of bolt 4. |
| Bolt 5 | ||
| X | mm | X of bolt 5 (used when n ≥ 5). |
| Y | mm | Y of bolt 5. |
| Bolt 6 | ||
| X | mm | X of bolt 6 (used when n = 6). |
| Y | mm | Y of bolt 6. |
| Load | ||
| Load X component | kN | Horizontal component of the load. |
| Load Y component | kN | Vertical component of the load (negative downwards). |
| Load X position | mm | X coordinate of a point on the load’s line of action. |
| Load Y position | mm | Y coordinate of that point. |
| Shear capacity per bolt | kN | Design shear capacity of one bolt from your code (see the bolt shear and bearing tool). |
Method and formulas
- Centroid = mean of bolt positions; M = (lx − xc)Py − (ly − yc)Px.
- Direct shear: Px ÷ n, Py ÷ n per bolt.
- Torsional shear: Fx = −M (y − yc) ÷ Σr², Fy = M (x − xc) ÷ Σr², with r² = (x − xc)² + (y − yc)².
- Resultant per bolt = vector sum; the largest governs.
- Example: 20 kN at 300 mm on the default 4-bolt pattern puts 21.506 kN on the critical bolt.
Limitations
- Elastic method with equal bolt stiffness and rigid plate; the instantaneous-centre method gives higher capacity for ductile bolts.
- Out-of-plane loads (prying, tension) are not included.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check bracket and gusset bolt patterns
- Find the critical bolt in a group
- Compare bolt layouts
Who it is for
- Design engineers
- Maintenance fitters
- Quality inspectors
What you get
- Group centroid and moment
- Force on each bolt
- Critical bolt and utilisation
Interpreting the result
- Spreading bolts further from the centroid reduces the torsional share.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1535, 1720–1735. Topic reference; no source tables or recommended settings are reproduced.
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