Week - 3 Drop test Challenge

Aim

To perform a drop test analysis on the given cell phone model.

Introduction

Drop test is free fall test of the component. It is generally performed to check the ability of product to withstand suddenly applied loads. Drop test is one of the functional test requirements of crash frame for certification, Hence crash frame has to quality through the drop testing as per standard.

fig:- Drop orientation of cell phone

Unit: Kg mm ms

Step1: Import the mesh model

Open LS-PrePost software, Import the mesh generated model by clicking->File->open->LS-Dyna ketword file.

Step:2 Set-up

Section

Model and part->Keyward manager->Section-> solid

Materials

Model and part->Keyward manager->Mat

for Baseplate steel material is used having material properties `rho = 8 e-6 (kg)/(mm^3)` `E=205 Gpa` and `mu = 0.3`

 for phone cell piecewise plinear plasticity (24) is used.

Contact

Model and part->Keyward manager->Contact

Velocity

First of all create set of nodes by Model and part->Create entity->set data->create and select the phone cell part.

Model and part->Keyward manager->initial->Velocity

Here the drop of the cell phone will be free fall. the gap between the baseplate and cell phone is about 20 mm.

 

Boundary Condition

First of all create set of nodes by Model and part->Create entity->set data->create and select the baseplate part.

Model and part->Keyward manager->Boundary

Model check

Go to model checking click on keyword check

Since warning are there which can be ignored and proceed to simulate the analysis.

for simulation to run, open LS Run and run

 Results & Analysis:

Energy

•  From the above graph, we can say that, when phone touches the rigid wall ,kinetic energy decreases and internal energy increases
• Also, we can see the Energy conservation is followed, total energy remain constant through the analysis.
• Hourglass energy remain zero due to fully intergreted element performulation 

Contact force

Here we can see the resultant contact force on the phone due to impact at 2 ms is 34.5 kN

Displacement

from graph we can see the displacement on cell phone when impacting on rigid wall.

Learning outcomes

Familar with Graphical user interface of LS-DYNA

Applying Section, materials, part, Boundary condition,initial condition and requsting output files

Post processing the result

Conclusion

Drop test analysis is performed, drop test simulation plays an important role in investing impact behaviours and identifying weak point of a cell phone at design stage since testing is expensive and time consuming.