Week 5 Bending of iPhone

Objective - simulate the bending of iPhone

Case 1 - Simulation as per the given geometry.

Case 2 - Move the bottom fingers from their defined position to the given position X= 22.5mm & Z= 10mm and obtain the results for the simulation.

Also 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

Obtain - directional deformation, Life of aluminium alloy case, Factor of Aluminium alloy NL

Solution - First we open the Work Bench and edit the engineering Data.

We add Polyethylene, Aluminium Alloy NL.

In order to get glass as the material we duplicate the Polyethylene and change the properties

we add the S-N curve given to us in objective to the properties of Aluminium alloy NL

Material Properties Aluminium Alloy NL

Material Properties Polyethylene

Material Properties Glass

Now we upload the model to the geometry and open it in space clam and see if there are any discontinuities in the model.

Update the model to the mechanical module. And Opening the module.

We change the material for screen to glass the frame of the phone to Aluminium alloy NL and the inside of the phone to Polyethylene. The fingers are given structural steel property and the behaviour to rigid except the one pusing finger at the bottom.

In the contacts we add a frictionless contact between fingers and I phone. We delete the unwanted contact between the fingers.

Contact

Joints

We add fixed joints to all the fingers on top of the I phone.

And we add a translation joints to the two bottom fingers.

Meshing the model with face sizing 5 mm on surface of frame and 10 mm element size for rest of model.

now in the analysis settings we execute the simulation in 8 steps.

Setting for all 8 steps is

Fixed support is given to the edges of the inside of the I phone.

Displacement is given to the sides of the frame in Y direction and constraned the movement in X and Z direction.

Joint loads are given to Both the Pushing fingers.

Case 1 - the pusing fingers are at the edge of the frame.

Directional Deformation In Y direction

Equivalent stress on base of clip

Life of the frame

case 2 - The pushing fingers are towards the center of the frame. Analysis settings for Case 1 and 2 are the same.

We can move the fingers in space Claim with the option of move.

Directional Deformation In Y direction

Equivalent stress on base of clip

Life of the frame

Model Link

https://drive.google.com/file/d/1pS0Vj9hx586doT8XLRx91QDFWH6-zDx2/view?usp=sharing

Simulation Link

https://youtu.be/Nm3ilgpmVN8

Comparison Table

	parameters		Equivalent stress (max)	Directional (Y axis)Deformation (max)
			MPA	MM
1	Case 1		504.03	4.4341
2	Case 2		425.25	3.234

Conclusion - The stress induced and the directional deformation is more in case 1as compared to case 2.

This is because the pushing fingers are towards the edge of the frame for case 1 and at the center for case 2.

We can see that the life is zero for the case 1 in the area near the volume button. It means that if the Iphone is loaded even a single time with 504.03 MPa alternating stress the area near the volume button will fail.

Similarly for the case 2 when the pushing fingers are at the centre the area near the centre of the frame will fail when the model is loaded with 425.25 Mpa alternating stress.