Week 5 Bending of iPhone

Objective:

• To 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

  Require 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:

Step 1: Engineering Data

• Add Aluminum NL material to drop down list of materials.
• Add poyethylene to the list from list of general materials
• Duplicate this material and rename it glass. Add the following specification to the material.

• Check for the above four listed materials in your model tab.

For Case 2: Insert the SN curve and add the following listed data.

Step 2: Geometry

• Right click on geometry and Import the Skill_Lync_Iphone_Bending.x_t extension file
• Rename the Static Structural tab as Iphone Bending.
• Update the Static Structural tab and proceed to edit geometry in spaceclaim.
• Check for the Surface limit if you have Ansys student version and merge some under repair tab if you need to reduce surface count.
• update the Model tab and open click Edit.
• For case 2 open spaceclaim under Move tab enter XYZ coordinate to move thumb L and R relative to give cordinates by amount X= 22.5mm & Z= 10mm.

Step 3: Model and Meshing

• Open Model and under geometry assign names according to convenience for better understanding.
• Rename geometries as Display, Frame,Inside, Thumb R(Pushing Finger), Thumb L, and rest all as Finger 1-8.
• Assign Aluminum NL material to Frame.
• Assign poyethylene material to Inside.
• Assign Glass material to Display.

Step 4: Connections

• Contacts:- Define the contact faces between Display to frame as Bonded type of contact.
• Define the rest of contacts as Frictionless.
• Insert Fixed Body to ground Joint for Finger 1-8.
• Insert Translational Joint Body to Ground for both the thumbs.
• insert face sizing for the contact part of thumb and frame as shown below.
• Use Augmented Lagrange as Formulation method.

Step 5: Setup

• Insert 8 number of steps for analysis.
• Insert Fixed support for edge face of inside body as shown.

• Insert displacement for 4 side face of frame to lock its movemnt in X and Z direction

• Insert Joint load for Thumb L defined by displacement type with tabular data of displacement from 0,2,4,6,8,6,4,2 mm with retraction effect.
• Similarly duplicate this joint and attach this to Thumb R body.

Results:

CASE1

CASE2

• Comparison of case 1 & 2 results:

Case #	Equivalent Stress Frame Aluminum alloy NL	Directional deformation for the model Y-dir	Factor of Safety- Aluminium Alloy NL (minimum)	Life of the Aluminium alloy
Units	MPa	mm		Cycles
Case 1	655.69	5.5187	NA	NA
Case 2	405.12	4.207	0.19747	1e+008

Conclusion:

From results comparison we see that stresses produced (Frame body only) in case 1 are higher than case 2 where the frame is bent from central area. The Life cycle of part where frame is bent shows the results as 0 because the material is bent and damaged. Corresponding probes indicate the cycle life of frame in parts where it is damaged and not damaged (1e+008 cycles in parts where its not damaged and 0 cycles where its damaged). The Factor of safety has dropped below 1 as the frame is damaged and can take no more loading.