Butt Weld Static Strength.xlsx

A full penetration butt weld is likely to be as strong as the parent plate. Compare with fillet weld calculation.

The static strength of a simple butt weld refers to the maximum load the weld can withstand before failure under static loading conditions. To determine the static strength of a simple butt weld, you can follow these steps:

1. Identify the weld geometry and material properties:

• Weld length (L): The length of the weld along the joint.
• Weld throat thickness (t): The minimum distance from the root of the weld to its face. For a full penetration butt weld, the throat thickness is equal to the thickness of the welded plates.
• Weld material strength: The weld material's yield strength (Fy) and ultimate tensile strength (Fu).

2. Calculate the weld's cross-sectional area (A):

A = L * t

3. Determine the weld's static strength under axial loading:

• Axial load capacity (Pa): The maximum axial force the weld can carry before yielding or rupture.

Pa = A * Fy (for yielding) Pa = A * Fu (for rupture)

Choose the smaller value of Pa to ensure the weld doesn't fail under either yielding or rupture conditions.

4. Determine the weld's static strength under shear loading:

• Shear load capacity (Pv): The maximum shear force the weld can carry before yielding or rupture.

Pv = 0.5 * A * Fy (for yielding, assuming a 0.5 shear stress reduction factor) Pv = 0.6 * A * Fu (for rupture, assuming a 0.6 shear stress reduction factor)

Choose the smaller value of Pv to ensure the weld doesn't fail under either yielding or rupture conditions.

5. Evaluate the weld's static strength under combined loading:

If the weld is subjected to both axial and shear forces (Pa and Pv), you can evaluate the weld's static strength using the interaction equation:

Pa / Pa_allowable + Pv / Pv_allowable ≤ 1

If the inequality is satisfied, the weld is considered safe under the combined loading.

It's important to consult relevant design codes and standards to ensure the appropriate safety factors, material properties, and weld geometry are used in the static strength calculations.