'Drop_Test_Iphone_Case' simulation project by Madan_Mohan


#1

I created a new simulation project called 'Drop_Test_Iphone_Case':

Drop Test of Iphone Case


More of my public projects can be found here.


#2

In this project, the drop test of iPhone casing is simulated to see the maximum stress values attained during the impact of the phone with the floor.

CAD Model

The 3D CAD Model of the iPhone casing is taken from ‘Grabcad’ website provided by the user IGOR.
The not so important complex futures such as camera, sensors, switch buttons and apple logo were removed and the individual parts were merged as a single solid part using the boolean operation in the ‘Onshape’ online CAD tool. The floor is modeled as a rectangular solid below the iPhone casing and the iPhone casing is rotated to an angle of 60 degrees with respect to the floor.

Meshing

The 3D CAD model is uploaded as a STEP file to SimScale. The Mesh is generated using the Tetrahedralization with refinements option. Mesh refinement is done on the bottom edge of the casing which will be in contact with the floor.

Simulation

The analysis type Dynamic Analysis-Advanced is used for this project to simulate the time dependent behavior of the casing. Acceleration due to gravity of 9.81 m/s² is applied to the casing. The floor is modeled as a rigid solid constraining displacement in all directions. The phone casing is initiated with a downward velocity of 8 m/s. The material assigned for the casing is Aluminium with Young’s modulus as 69e+9 N/m², Poisson’s ratio as 0.32 and Density as 2700 kg/m³. The floor is taken as the master part since it is rigid and the casing is taken as slave part. ‘Implicit type’ time integration is used and 4 computing cores are used for the analysis. The time taken for the simulation is 22 minutes. The Maximum Von Misses stress achieved during the simulation is found out.

Result

von Misses stress in iphone


#3

Hey @Madan_Mohan!

Nice analysis! Great job! :smile: Only some suggestions for improving the analysis.

  1. Your impact is not properly captured since it happens between 0.001 to 0.002 which is done only in a single timestep. After the impact you don’t need to analyse it much further. So until 0.003 it will be fine to end the analysis. In order to capture the impact properly, you can apply defined timestepping via table upload. In your case you can make a .csv file by just copying the values below in excel sheet or notepad and saving it as .csv file.

        time, timestep
        0.001, 0.001
        0.002, 0.0001
        0.003, 0.001
    

    Once this is done you can upload this table under Simulation Control. The solver will than follow this time scheme for the analysis. Also make sure that Simulation interval [s] is set to 0.003. You can also reduce the timestep to 0.00005 for timestep between 0.001 and 0.002 in order to capture the impact more accurately, but this will in turn increase the simulation time and also the result size. You can have a look at this project in order to see how the table can be uploaded.

  2. In your case since the rotation of the iphone is too high after 0.004 seconds, your iphone 6s is transforming to iphone 6s plus :yum: which is due to Geometric behavior being set to linear. If you want to simulate it that further, you should switch it to nonlinear in order to let your iphone 6s remain 6s after the impact. For the case of maximum runtime of 0.003 you can leave as it is.

Hope this helps. If you have any further question/s, feel free to ask. Happy Simulating!

-Ahmed (@ahmedhussain18)