Bending of iPhone

Bending of iPhone

In this challenge we will simulate the bending of iPhone and fatigue life of the Aluminium alloy frame using static structural assigning different materials to the various components of iPhone. Various steps which are undertaken are explained below-

1. First, we change the geometry by moving both the push fingers to the new position to X=22.5mm and Z=10mm by Move operation in Spaceclaim.
   
   
2. After this, we have selected Aluminium alloy NL, Polyethylene, Structural steel, Aluminium alloy from material library and Glass by modifying properties of Polyethylene according to the video in order to assign it to the various components of the iPhone like screen, frame etc.

1. Opened the ANSYS mechanical and assigning Aluminium alloy NL to the frame, Glass to the screen, Polyethylene to the body and structural steel to the fingers by default. Also changing the stiffness behaviour of all the fingers and one push finger to the Rigid.

1. Deleted the contact between the fingers-fingers and providing frictionless contact between all other components which were generated by default by ANSYS with appropriate settings which were mentioned in the video.

1. Two translation motion joints are provided to each push finger along X-axis and fixed joint to the rest of fingers. These joints can be seen below-

1. Mesh is produced by providing face sizing of 4mm between the push finger face and lower frame face which are in contact. Resulted mesh is shown below-

1. Before setting the boundary conditions, various analysis settings are changed according to the video which can be seen below-

1. The fixed geometry is provided to two opposite faces of the body, displacement is provided to the frame to resist its motion along Z and X axis and displacement is provided to both push finger till 8mm in steps of 2mm along X axis of the push fingers and after step 4 it returned back to 0mm at step 8. These boundary conditions can be seen below -

Boundary condition

1. Results

• Directional Deformation of model

Max value=4.081mm

Explanation- In this directional deformation is calculated along Y axis. As the two push fingers have maximum displacement of 8mm at step 4, so at step the deformation is 7.75mm. But as the finger come back to the initial position, the load get removed and model shows the plastic deformation of 4.08mm as the material assigned to the frame is Aluminium NL.

• Factor of safety of screen made of Glass

Min value=0.473

Explanation- The screen have minimum FOS of 0.43<1 at step 8, so it show that it get failed as stress generated in screen is more as compared to the Glass yield stress. Also at step 4 when there is maximum deformation, it shows FOS of 0.13, so the screen will get fail much earlier even before the step 2.

• Factor of safety of frame made of Aluminium alloy- In this case we have used the material Aluminium alloy rather than Aluminium alloy NL as it was not giving result and showing error. Thus, we have taken aluminium alloy to get a result.

Min value=0.101

Explanation- The frame have minimum FOS of 0.10<1 at step 8, so this will also get fail as stress generated in fram is more as compared to the Aluminium alloy yield stress. At step 4 it shows FOS of 0.06 becouse of maximum deformation at the step.

• Life of frame made of Aluminium alloy- In this case also we have used the material Aluminium alloy rather than Aluminium alloy NL as it was not giving result and showing error. So, provided alternating stress mean stress value in table form to the aluminium alloy as values was given in the challenge and solved it.

Min value=0

Explanation- For this fatigue test, we have taken reverse type of loading and Goodmann mean stress theory. After this, we have determine life. But as we can see in the image, the red will not survive even 1 cycle of reverse loading, whereas the blue portion can survive upto infinite number of cycles of reverse loading.

Conclusion- The phone will get fail at this amount of displacement of push fingers as we can see in the above results. So in order to save it we should change the material or amount of displacement given by the push finger to the phone.