Week 5 Bending of iPhone

Apple I-Phone Bending Simulation

Objective: To simulate the bending simulation of i-Phone body with cover and to observe

the behaviroul changes on the back cover with aluminium material respectively.

GEOMETRY:

Fig. Geometry of CASE I

From the above Geometry the above 8 fingers are termed as Rigid and the remaining bottom fingers viz thumbs are consideredn as flexible as they are goin to put the pushing force on it.

JOINTS AND CONNECTION:

CONTACT analysis: In the contact generated in the simulation For CASE I and CASE II will be the same just the positioning of the bottom two fingers wil be adhered for the CASES respectively.

Fig.Contacts Generated for CASE I

In the above case the contact generated for the pushing fingers is taken as frictionless and the contact betwween display to inner body is fixed is as shown above.

JOINT ANALYSIS:

From the bove Contact analysis made the Joints are defined as Fixed for the fingers at the top and translation joint is given to the both pushing fingers as shown below:

Fig. Joints For CASE I

MESH: The Mesh Generated is as shown Below

Fig.Mesh Generation

Fig.Element Quality

As Said the Element quality is a combination tet and hex mesh basically and the quality averages to 0.34 respectively. And the number of elements comes out to be 9406 with 222206 nodes

BOUNDARY CONDITIONS:

Fig. Boundary Conditions

From the abive figure the fixed support is given to the insde body and the displacment is constrained in X and Z direction so as to observe the displacement in Y direction due to translational joint.

SOLUTION FOR CASE I:

Fig. Total Deformation For CASE I

Fig.Von Mises Stress For CASE I

Fig. Equivalent Strain For CASE I

Fig. Pressure Acting on Back Cover

Fig. Force Reaction

CASEII: 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

GEOMETRY FOR CASE II:

Fig. Geometry For CASE II

As the Position of the fingers is moved at the Centre of the back cover, So just the geometr will change rest of conacts boundary conditions and mesh respectively will remain Same.

SOLUTION FOR CASEII:

Fig.Total Deformation CASE II

Fig. Von Mises Stress For CASE II

Fig.Strain for CASE II

FATIGUE analysis for Life Prediction:

Fig. Stress and Cycles for the analysis

Fig. Stress Distrubution

Fig.Life Cycles

Fig. Force Reaction

Fig.Pressure For CASE II

CONCLUSION:

Sr.No	CASES	Total Deformation(mm)	Von-Mises Stress(MPa)	Equivalent Strain	Pressure(MPa)
1	CASE I	5.68	625.53	0.0088	265.20
2	CASE II	4.27	393.04	0.0057	161.99

From the above table it is quite clear that the values of CASE II are less than that of CASE I becasue at the edge the particle or granular binding is weak for the material as compared to the centre ones and as the intermoelcular binding or the grains are more binded at the centre as compared to the corener ones.