Fillet Weld Design
Part 1: Directional Method
Hi friends, 👋👋
After looking at butt welds 2 weeks ago, today we’ll cover how to calculate and design fillet welds. According to Eurocode EN 1993-1-8 4.5.3.1, either the directional method or the simplified method can be used to verify fillet welds.
So this week, we’ll show how you use the directional method, and next week, we’ll go through the simplified method.
→ Click here for the full article ←
So here are the steps, we need to follow:
Calculate the internal forces at the location of the weld
Define the geometry properties of the fillet weld
Define material properties
Calculate the design stresses and resistance of the weld
Check utilization
We’ll use the example of a fillet weld connecting a steel plate with SHS profiles. ⬇️⬇️
So let’s get started. 🚀🚀
#1 Internal forces
For the design, we’ll need the normal and shear force and the bending moment. These depend on the applied loads but also the static system. If it’s a simple, statically determinate structure, you can calculate the internal forces by hand. But in most cases, you probably use a FEM program like Autodesk Robot.
For our example, we use the following (design) internal forces.
#2 Define the geometry properties of the fillet weld
The fillet weld has the following dimensions:
#3 Define material properties
#4 Calculation of the design stresses and resistance of the weld
The stresses in the weld are calculated from the internal forces acting in the plate.
Resulting stress:
The fillet weld verifies if the following 2 criteria are satisfied (EN 1993-1-8 (4.1):
Criteria 1:
Criteria 2:
#5 Utilization
Criteria 1:
Criteria 2:
Conclusion
As butt welds, designing fillet welds isn’t that difficult, is it? We find the internal forces acting in the connection, define geometric and material properties, and calculate the stresses in the weld and the resistance stress. That’s it.
Hope this guide helped you understand the directional method for fillet welds better.
And as said earlier, we’ll cover the simplified method next Wednesday.
So see you there.
Cheers,
Laurin. ✌️✌️