Week 5 Bending of iPhone

Aim-

We have to perform structural analysis for Iphone bending & is to be performed for 2 different cases. Variation of certain settings is also to be performed and conclusions are to be added to the report.

 

Objective-

simulate the bending of iPhone as per the given cases below

Case 1: Simulate the model as it is given in the video

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

 

Results and Deliverables

• Obtain the directional deformation for the model
• Factor of Aluminium Alloy NL
• Life of the Aluminium alloy for the case
• Compare the results and present with the conclusion.

Procedure-

• We have to first start as new project in the ansys workbench and select the proper material for the Iphone and fingers.
• Here material has been specified in the project so we will select materials as stated.
• For cover specify material as aluminium alloy NL, Polythelene to inner part and glass to screen and rest fingers as structural steel.

For Case-2-

• We have to add S-N curve for it in Aluminium Alloy NL.

• Now we have to import the model for that right click on the geometry tab and hit import>>then select the file from saved location and hit ok.

Case-1-

Case-2-

• The bottom fingers from their defined position to the given position X= 22.5mm & Z= 10mm.

• Now we have to open mechanical Model and wait for a while till our model loads.
• For cover select material as alluminium alloy NL.
• We have to now remane the mobile parts name and the proceed further for connections.

Connections-

• Now we have to delete the two unspecified connections and then need to rename connections.
• Since Screen and covers will be sticked together so we will use bonded there and rest of them as frictionless. 

• Now we have to define joint loads, right click on connections>>joints>>select singers one by one and define joint loads.

Mesh-

For Case-1 & 2

• Go to mesh then right click and the click on insert and select sizing.
• select size of 4mm as mesh size for bottom fingers and cover parts.

• For rest parts keep default mesh size.

Analysis setting-

• Go to analysis setting and set number of set as 8 and refer below setting for steps selected.
• Keep output parameters as all yes.

• Now we have to apply fixed support load to inner part of iphone on both edges as shown below,

• Now we have to give dispalcement setting to punch as perbelow snap and select top and top two side faces of cover.
• Keep Y-axis free and rest as 0mm ramped.

• Now for both fingers define the boundry condition as follows, here select whole body of fingers and apply displacement loads.
• Apply loads in X-axis only.

Solution-

• Here we have to define directional deformation, to do so right click solution>>insert>>deformation>>directional, select Y-axis (for cover).
• Now for stress right click on the solution>>insert>>stresses>>equivalent (von-Mises) (for cover).
• Now for strain right click on the solution>>insert>>strains>>equivalent (von-Mises) (for cover).
• Now for stress right click on the solution>>insert>>stresses>>equivalent (von-Mises) (for whole body).
• Now for contact tool right click on the solution>>insert>>contact tool>>contact toll>>right click on contact tool>>pressure.
• Now for force reaction right click on the solution>>insert>>probe>>force reaction.

Case-1-

• Select the stress tool, right click on solution>>insert>>stress tool.

Note- for this reason we have defined tensile yeild strength in alunimium material.

Case-2-

• Select the fatigue tool, right click on solution>>insert>>fatigue tool, again right click on fatigue tool>>life & safety factor for cover only.
• refer below settings in fatigue life.

Result-

Case-1-

1. Directional Deformation-

2. Equivalent Stress (For Cover)-

3. Equivalent Elastic Strain(For Cover)-

4. Equivalent Stress-

5. Contact Tool (Status)-

6. Contact Tool (Pressure)-

7. Force Reaction-

8. Stress tool (Safety Factor)-

Case-2

1. Directional Deformation-

2. Equivalent Stress (For Cover)-

3. Equivalent Elastic Strain (For Cover)-

4. Equivalent Stress -

5. Contact Tool(Status)-

6. Contact Tool (Pressure)-

7. Force Reaction-

8. Fatigue Tool (Life)-

9. Fatigue Tool (Safety factor)-

Result Comparison-

Cases	Directional Deformation (mm)		Equivalent Stress (MPa)		Equivalent Elastic Strain		Safety Factors
	Min.	Max.	Min.	Max.	Min.	Max.
Case-1	-0.9241	5.4147	4.3882	612.84	0.00017	0.008873	0.45689	Stress
Case-2	-0.3077	4.3806	7.2058	390.19	0.00029	0.005525	0.41005	Fatigue

• From above table we can say that the max stress in case-1 is more than 1.5X of case-2 in which load is apply nearly at the centre.
• Also Strain is also lesser in case-2 as compared to case-1,which indicates that case-2 has less plastic strain.
• Also load applied on case-2 is nearly at at centre so load distribution is also proper, thats why it is showing lesser deformation as compared to case-1.
• Since from above deformation result we can observe that min value is in negative which shows that after removal of load cover tries to regain it's original shape.
• Safety factor for cases are nearly same.

Animated results-

1. Case-1

Directional Defromation-

Equivalent Stress (For Cover)-

Equivalent Elastic Strain (For Cover)-

Equivalent Stress-

Contact Tool (Status)-

Contact Tool (Pressure)-

Force Reaction-

Stress Tool (Saftey Factor)-

2. Case-2

Directional Defromation-

Equivalent Stress (For Cover)-

Equivalent Elastic Strain (For Cover)-

Equivalent Stress-

Contact Tool (Status)-

Contact Tool (Pressure)-

Force Reaction-

Fatigue Tool(Life)-

Fatigue Tool(Safety Factor)-

Conclusion-

• From above analysis and obdervation we can say that on repitative loads, iphone can with stand more load in centrally loaded condition.
• When it is loaded from side of cover in will fail and may break in ealry loading conditions.
• In both the cases stress is going beyond the max yield limit which can cause plastic deformation.
• To make iphone body more durable some filler material must be added to it to increase the strength.