ANSYS- Verification of Weld Joints

Weld Material used:

Case 1. Stainless Steel: In this case, the material of the plates must also be the same. Use Stainless steel for both weldments and plates. No need to add flux to the weldments.

Case 2. Aluminium Alloy:The material to be chosen for this case is Aluminium alloy(high strength, wrought). [Plate material to be used is stainless steel]

Case 3.Bronze: In order to simulate "Brazing", you should be using bronze as the weld material. Assign Stainless Steel to both plates and Copper to the "Ribs".

Run the simulation for a load of 15000N that is to be applied at the rectangular hole in the small plate.

SOLUTION:

Verification of Weld Joints setup:

Geometry and Material:

Add the appropriate materials that are needed to be used to the Engineering Data.

The Geometry includes the following components: 2 Plates, 2 connecting Ribs and 26 Fillet Welds.

Three Cases are created in the project as shown below:

Materials are appropriately selected for each of the three cases as follows:

	Material of Plates	Material of Ribs	Material of Weld
Case 1	Stainless Steel	Stainless Steel	Stainless Steel
Case 2	Stainless Steel	Stainless Steel	Aluminium alloy
Case 3	Stainless Steel	Copper	Bronze

Contact:

• Two bonded contacts are created for each of the 26 welds, with the two plates that the weld connects.
  
  
  
• 5 Frictional Contact of f=0.2 are created between each of the contacting plates.
  
  
  

Mesh:

The Mesh is created such that the stresses converge. Body sizing is used each of the parts appropriately.

Analysis Settings:

The analysis is set up for a single step with default settings.

Boundary Conditions:

The overall Boundary Conditions are shown below:

1. A Fixed Support is setup at the 5 holes of the Base Plate:
   
   
   
2. A 15000N Force is applied to the rectangular hole of the Sub Plate in the Y-Direction:
   
   
   

Solution:

The desired output variables are selected in the solution as shown above. The File is then solved for.

Equivalent Stress- Only welds
Directional Deformation (Y- Dir)- All Bodies
Equivalent Elastic Strain- All Bodies (Plastic Strain is negligible)
Stress Tool- Only welds
Contact Tool- All 5 contacts

Case comparison:

Material Properties Comparison:

Material	Young's Modulus	Yeild Strength
Stainless Steel	193GPa	210MPa
Aluminium alloy	73.8GPa	363MPa
Bronze	80GPa	144MPa
Copper alloy	110GPa	280MPa

Equivalent Stress in Welds:

The Maximum Equivalent Stress for all three weld cases is plotted against the ramped force applied.

Here, the curves that deviate from the linear path have entered the non-linear region and therefore, a non-linear material model has been used for them.

The above graph can be explained on the basis of the stiffness (Young's Modulus) of the materials. The applied force will be divided between the connecting parts. The stiffer parts carries more load than the less stiffer. Since the Plates are made of Stainless steel (E=193GPa), while the weld is of different materials in accordance to each case, the stresses in the weld is of the order:
Stainless Steel(E=193GPa)> Aluminium Alloy(E=73.8GPa)> Bronze(E=80GPa)

The locations of maximum and minimum equivalent stress are shown below. The weld tip shown below is the region of highest stress and potential point of failure:

Directional Deformation (Y-Dir):

The Directional Deformation in the Y-direction comes to be of prime importance. The deformation for the given load of 15000N is inversely proportional to the overall stiffness of the system. The expected order of maximum deformations is:
Case3> Case2> Case1.

The locations of maximum and minimum deformation are shown below:

Equivalent Strains:

The graph of the total equivalent strain is shown below:

In the above only Case 2 is within yeild region, while Case 1 and Case 3 have crossed yeild and have undergone plastic deformation.

The weld tip shown below is the region of highest strain:

Conclusion:

The Aluminium Alloy weld is the best option as it has not yeilded under the prescribed force of 15000N. Brazing is the weakest weld option with the lowest yeild strength.