Week 3 Verification of Weld Joints

Verification of Weld Joints

OBJECTIVE:

• The objective of this challenge is to perform a static structural analysis and to Simulate three different types of welding by using three different weld materials such as Stainless Steel, Aluminium Alloy and Bronze cast. And to run the simulation for a load of 15000N that is to be applied at the rectangular hole in the small plate, as well as for each case, to find out the Directional Deformation and equivalent strain experienced by the setup and to Identify the weld joint that experiences the highest equivalent stress in each case and compare the results for all three cases.

INTRODUCTION:

• A welding joint is a point or edge where two or more pieces of metal or plastic are joined together. They are formed by welding two or more workpieces (metal or plastic) according to a particular geometry. There are five types of joints referred to by the American welding society: butt, corner, edge, lap, and tee. These configurations may have various configurations at the joint where actual welding can occur.

CAD Model:

• The CAD Model consists of Two plates, two ribs and and 26 weld joints. Holes are provided to the bigger plate for providing the support with the wall and a small rectangular hole is provided to the smaller hole, for adding the load to it. The two plates and two ribs are connected each other by 26 weld joints.

PROCEDURE:

• Open the ANSYS Workbench software. Under the Analysis system select the Static structural and wait for few seconds to pop up the window, which contains Engineering data, Geometry, Model, setup, Solution and Results.

• Under geometry import the Weld Joints model.

• Update the model by right click and edit the Model for Preprocessing. Wait for few seconds and ANSYS Mechanical will open

• Assign the material to the model, By classifying the required needs into three cases, And assign material to the model based on the cases.

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", we should use bronze as the weld material. Assign Stainless Steel to both plates and Copper to the "Ribs".

Material properties:

• Frictional contact between the two Plates and the two ribs are Defined with a frictional coefficient of 0.3.

• Insert a fixed support at the holes to the Bigger plate in order to act as fixed. So click on static structural go to insert and select fixed support. Then select the holes

• Then apply a force of 15000N at the rectangular block by clicking on static structural go to insert and select Force. Then select the rectangular block and apply the force=15000N

• In ANSYS automatic mesh will be performed with Default mesh size and change the mesh size as 7mm. (based on grid dependency test reducing the element size further doesn't effect the result and element size 7mm is assigned.) (i.e. Ansys student version will have a limited number of elements and nodes.) Apply the mesh size of 7mm to the two plates by selecting body sizing.

• Analysis settings - Change no. of steps as 1,

auto time as program control,

large deflection on,

solver type as program controlled.

• Now request for the outputs such as equivalent stress, equivalent elastic strain, directional deformation, stress and contact Tool.

Solver output

CASES:

• 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".

RESULT:

1.Simulation results for case-1 the material of the plates, ribs and weldments are same (i.e. Stainless steel)

• EQUIVALENT STESS-

• DIRECTIONAL DEFORMATION (Y-Axis) -

• EQUIVALENT STRAIN-

• EQUIVALENT STRAIN ON RIBS-

• EQUIVALENT STRESS ON WELDS-

• SAFETY FACTOR-

• CONTACT STATUS-

• CONTACT PRESSURE-

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

• EQUIVALENT STRESS-

• DIRECTIONAL DEFORMATAION (Y-AXIS)-

• EQUIVALENT STRAIN-

• EQUIVALENT ELASTIC STRAIN ON RIBS-

• EQUIVALENT STRESS ON WELDS-

• SAFETY FACTOR-

• CONTACT PRESSURE

Case 3. Simulation results of Bronze: In order to simulate "Brazing", we should be use bronze as the weld material. Assign Stainless Steel to both plates and Copper to the "Ribs".

• EQUIVALENT STRESS-

• DIRECTIONAL DEFORMATION(Y-AXIS)-

• EQUIVALENT STRAIN-

• EQUIVALENT ELASTIC STRAIN ON RIBS-

• EQUIVALENT STRESS ON WELDS-

• SAFETY FACTOR-

• CONTACT PRESURE-

MATERIAL	EQUIVALENT STRESS (MPa)	DIRECTIONAL DEFORMATION (Y-Axis) (mm)	STRAIN	RIB STRAIN	EQUIVALENT STRESS AT WELDMENTS (MPa)
Stainless Steel	MAX: 277.32 MIN: 0.11997	MAX: 0.2961 MIN: -0.01771	MAX: 0.001725 MIN: 7.4445e-7	MAX: 0.0003033 MIN: 1.2696e-5	MAX:238.88 MIN: 1.498
Aluminum	MAX: 296.69 MIN: 0.203	MAX: 0.3841 MIN: -0.02149	MAX: 0.002854 MIN: 1.1059e-6	MAX: 0.0006056 MIN: 2.043e-5	MAX: 210.24 MIN:1.0822
Bronze	MAX: 285.86 MIN: 0.1175	MAX: 0.3378 MIN: -0.01654	MAX: 0.002613 MIN: 7.1863e-7	MAX: 0.0004068 MIN: 2.1173e-5	MAX: 208.86 MIN: 0.7118

• The above tabular data shows the variations in the equivalent stress and directional deformation of various material such as Stainless Steel, Aluminium and Bronze. Aluminium material experiences more stress and directional deformation where compared with case-1 and case-3.

Conclusion:

• From the above result we can conclude that the equivalent stress and maximum directional deformation takes place in Case-2. The maximum deformation takes place in case-2 because in this case the material is Aluminium

• From case-1, the ribs, plates and weldments are assigned with same material as stainless steel and experiences more stress at weldments due to high yield strength of material as well as in case-2, the stress at weldment is high when compared with case-3.

• The usual causes of material failure are incorrect materials selection, incorrect processing, incorrect manufacturing procedures, inadequate design or incorrect use. Fracture is the separation of a body into two or more pieces as a result of an imposed stress. Here the aluminum material will not fail as the FOS of this material is 1.22 when compared with other two.

• FOS= YIELD STRESS/WORKING STRESS,

FOS of aluminium = 363/296.69= 1.22.

• Grid dependency test will be important for selecting the suitable mesh size.

Animation video: https://drive.google.com/drive/folders/1He_dhJfl2geKrr1L2uHt0lKY3aFaLzQr?usp=sharing