Week 5 Bending of iPhone

Objective:

To perform the bending test of iphone and to compare the results with another case where the bottom hand has been displayed from their defined position to the given position X= 22.5mm & Z= 10mm and obtain the results for the simulation and also to define the S-N curve for the Aluminium Alloy material as per values given below and determine the fatigue life results for the same.

Stress, MPa	Number of Cycles, N
225	10000
175	100000
143	1000000
110	10000000
80	100000000

Case setup & Execution:

• In the engineering data source we have selected engineering materials like polypropene, glass and Al alloy NL. 

         

         

• The CAD data has been imported for executing the analysis, For analysing the second case we have used translation transformation for the bottom finger.      
• In the mechanical module we have assigned materials to the different parts of the iphone like glass to the display, Al alloy NL to the frame and polyethelene to the inside parts of the phone. Except one bottom finger we have made rest of the finger as Rigid.
• In the connection region we have assigned bonded contact between the frame and the Display where as for rest of the contact has been assigned as frictionless.   
• In the contact region we have inserted the joints

1. Two Fixed joints between the fingers and the display.
2. Two Transtional joints for the bottom pushing finger.

• For the meshing we have used face sizing for the bottom portion of the frame and for the surfaces in contact with the frame of the pushing finger. The nodes are 21006 and elements 9930.
• In the analysis setting we have used 8 steps and other detail changes are shown below.
• we have applied fixed support to the inside part of the phone where as the frame has been given displacement (where X & Z components are fixed and Y components are kept free.).
• we have also assigned joints loads as translation to the pushing finger in as step of 8 as shown below.

Results:

Case 1

Directional Deformation:

Equivalent stress:

Stress intensity :

Case 2

Directional deformation:

Equivalent stress:

Life:

Stress intensity :

Discussion and Conclusion:

• From the above results it can be seen that the deformation in case 1 is 5.42mm where as the deformation is 3.29mm in case 2.
• The equivalent stress is 453.55 MPa in case 1 and in case 2 it is around 976.74 MPa.
• The stress intensity is 472 MPa for case 1 and it is around 1127.4 MPa for case 2.
• The life calculated through S-N curve for case 2 is 1E8 for the Al alloy frame.
• Thus due to the change in the pushing finger location we can observe that the deformation has decreased but the stress and stress intensity has increased for the case 2.
• The life calculated for the case 2 of the Al alloy frame suggest that it will under go infinite number of cycle before under going failure.

https://drive.google.com/file/d/11ZZGvC_Wi_w0Gn66Nl-PPG6WQPojDX5a/view?usp=sharing