How to use this calculator
- Choose weld pattern. Pick all-around rectangle or two vertical side welds.
- Enter group size. Use weld centerline width and height.
- Enter load and eccentricity. Use the in-plane load and distance from weld-group centroid to load line.
- Set weld size. Enter equal-leg fillet size and electrode class.
- Read utilization. The output combines direct and torsional line load at the critical weld point.
How it works
An eccentric in-plane load creates both direct shear and torsion on the weld group:
q = F / L M = F x e and the torsional line load varies as
q_t = M x r / J.
The calculator evaluates the corner points of the rectangular line weld and combines
direct and torsional components as a resultant line load. Weld stress is then
q_max / (0.707 x leg).
Worked example
Verified against the live calculator
A rectangular weld group 100 mm wide by 120 mm high with
10,000 N applied 100 mm from the centroid has direct line
load 22.73 N/mm.
Combining torsion gives a maximum resultant line load of 61.11 N/mm.
With a 6 mm E70 fillet, throat stress is 14.41 MPa and
utilization is 0.099.
Frequently asked questions
How do you calculate stress in an eccentric weld group?
The elastic method combines direct line load q = F/L with torsional line load q_t = M*r/J, where M = F*e and J is the weld-group line polar moment.
What weld patterns does this support?
It supports an all-around rectangular weld group and a two-vertical-side weld group. Both are treated as line welds about their centroid.
How is fillet weld throat stress calculated?
The maximum resultant line load is divided by the effective throat, 0.707 times the equal-leg fillet size.
What allowable weld stress is used?
The calculator uses allowable shear stress = 0.30*F_EXX for E60, E70 or E80 electrode strength. Apply your code-specific factors separately if required.
Does this include base metal checks?
No. The connected plate, HAZ, tear-out, block shear, fatigue, out-of-plane bending and code-specific resistance factors must be checked separately.
When should I not use this?
Do not use it for out-of-plane bracket bending, non-rectangular weld groups, flexible plates, fatigue-critical joints or final code design without engineering review.
Method & assumptions
- Elastic line-weld method for in-plane eccentric shear on rectangular weld groups.
- Fillet throat is
0.707 x leg; allowable weld shear is0.30 x F_EXX. For unequal fillets or root-opening allowance, check the straight-line throat on the weld throat calculator first. - The connected parts are treated as rigid enough for elastic weld-group distribution.
- Base metal, fatigue, out-of-plane bending, plate flexibility, instantaneous-center behavior and code resistance factors are not included.