Use this circular weld group stress calculator to estimate the weld stress in a complete circular fillet weld group subject to direct shear loads and a torsional moment about the weld group centre.
This calculator estimates the maximum resultant shear stress in a circular weld group. It combines direct shear stress from applied horizontal and vertical loads with torsional shear stress caused by a moment acting about the centre of the circular weld group.
The calculator provides:
This calculator is intended for a complete circular weld group. It should not be used for partial circular welds, intermittent welds or irregular weld groups.
Total circular weld length:
Effective throat thickness:
Total effective throat area:
Unit-line polar moment of inertia:
Throat polar moment of inertia:
Direct shear stresses:
Direct resultant shear stress:
Torsional shear stress:
Maximum resultant weld stress:
| Symbol | Description | Units |
|---|---|---|
| r | Radius to weld centreline | mm |
| h | Fillet weld size | mm |
| a | Effective throat thickness | mm |
| Vx | Horizontal shear load | N |
| Vy | Vertical shear load | N |
| T | Torsional moment about weld group centre | Nmm |
| A | Total effective throat area | mm² |
| J | Unit-line polar moment of inertia | mm³ |
| Ja | Throat polar moment of inertia | mm&sup4; |
| τmax | Maximum resultant weld shear stress | N/mm² |
Enter the circular weld group dimensions and loads, then click calculate.
| Result | Meaning |
|---|---|
| Total effective throat area | The effective weld area resisting direct shear load. |
| Direct shear stress | The average shear stress caused by Vx and Vy. |
| Torsional shear stress | The additional shear stress caused by moment T acting about the weld group centre. |
| Maximum resultant weld stress | The largest combined direct and torsional weld stress around the circular weld group. |
| Design allowable stress | The allowable weld shear stress divided by the selected safety factor. |
| Utilisation | The maximum resultant stress divided by the design allowable stress. A value below 100% passes this simplified check. |
This calculator is for a complete circular weld group subject to direct shear and a torsional moment about the weld group centre. It is a simplified preliminary calculation.
| This Calculator Includes | This Calculator Does Not Include |
|---|---|
| Direct shear from Vx and Vy | Partial circular welds or intermittent welds |
| Torsional moment about the weld group centre | Non-circular or irregular weld groups |
| Maximum resultant shear stress | Out-of-plane bending moment checks |
| Utilisation and pass/fail check | Fatigue, cyclic loading or fracture checks |
| Complete circular weld group behaviour | Parent metal tearing or plate failure checks |
This calculator first calculates the circular weld group throat area and polar moment. It then calculates direct shear stress from the applied shear loads and torsional shear stress from the applied moment.
For a complete circular weld group, the torsional shear stress is constant in magnitude around the circle. The maximum resultant stress occurs where the torsional shear stress acts in the same direction as the direct shear resultant.
For circular weld group properties only, use the Circular Weld Group Properties Calculator.
For a simple direct shear fillet weld calculation, use the Fillet Weld Strength & Size Calculator.
For further weld strength formulae and weld group properties, see the RoyMech reference page: Weld Strength Formulae and Weld Group Properties.
It calculates direct shear stress, torsional shear stress, maximum resultant weld stress, utilisation and pass/fail result for a complete circular weld group.
Yes, if the eccentric load can be converted into a torsional moment about the centre of the circular weld group. The moment can be entered as T in Nmm.
For a load acting at an eccentric distance from the weld group centre, the torsional moment may be estimated as:
where P is the applied load and e is the eccentricity from the weld group centre.
No. This calculator is intended for preliminary engineering checks. Final weld design should be checked against the relevant design standard, material properties, weld procedure and inspection requirements.
No. This calculator assumes a complete circular weld group. Partial circular welds, intermittent welds and irregular weld groups require different calculations.