Week - 3 Drop test Challenge

objective:-

Cell phone drop test is to be conducted by creating all the necessary input keywords:-

1 Material creation

2 Section creation

3 Assigning material & section to their respective parts

4 Definding boundary conditions & specifying initial velocity to the cell phone.

5 Creating the contact definition between the cell phone & rigid plate.

6 Model termination to be assigned

7 Binary_D3plot & ASCII_opction define

8 plotting the result

-This drop test of transit equipment (cell phones) follows military standerd (MIL-STD-810G) (516.6) procedure IV

*Procedure:-

-First of all the find the length of the cell phone.

-cell phone length=150.4 mm

-Distance between a node on the phone and the nearrest node on rigid plate =20.44 mm

-We use the unit system is:- Kg,mm,ms,KN,Gpa

1) Material keyword creation:-

-There are two types of model are available in this model:-

i) shell (rigid plate)

ii) solid (cell phone)

-The surface of rigid plate is made from the steel , usually these surfaces will be taken as concrete.

-Cell phone body is taken as aluminium, Usually the cell phone frames as made of aluminium alloys & plastic.

-For define material we use to this way:-

Model and part >keyword manager>all>MAT

-Choose MAT_20- Rigid assign for the shell (rigid plate)

-Choose MAT_24-piecewise_linear_plasticity assign for the solid(phone)

2) Section creation:-

-Session shell is taken for the rigid plate and session solid for the phone.

-For that we go to Model & part>keyword manager>all>section

-Session solid for the cell phone:-

-Section_shell for the rigid plate:-

3) Part and keyword assign:-

-After the creation of material & session , next step is create the part.

-Here there are two part are produce.

4)Boundary condition:-

-A boundary_spc keyword has been created to fix the rigid plate edged from moving during the impact.

-For that go to the model and part>create entity>boundary>spc

-After that select the area using the pick area opction & after that click on apply button.

5)Initial velocity:-

The initial velocity is provide for the phone.

-velocity is calculate using this formula:-

`v=√(2×g×h)`

here, v=veloc

g=Gravitational force

h=height of cell phone form the rigid plate

`v=√(2×9.81×10^(-3)×20.178)`

`V=0.629 mm/ms`

this value is very small then it is difficult to make the impact simulation within some ms of time, so we assume the phone is dropped from a height of 180 cm=1800 mm.

`v=√(2×9.81×10^(-3)×1800)`

`V=5.94 mm/ms`

-this velocity is provide towards the negative z-axis.

6) Contact creation:-

We create the contact between the phone & rigid plate.

-For that we go to Model and part>keyword manager>all> contact

-In the contact we choose the opction is Automatic_surface_to_surface.

-Here we use phone is a taken slave and rigid plate is taken a master.

*Control creation:-

-For the control cration we choose this path:-

Model and part>keyword manager>all>control

-Control_termination keyword is crated for the end time provide. we provide end time is 5 ms.

7)Database creation:-

*BINARY_D3PLOT:-

In this keyword the frequency with which the animation is to be crated will be given and is set to 0.1 ms.

*ASCII_OPCTION KEYWORD:-

-in this keyword

1) ELOUT-element data

2)GLSTAT-Global data

3)MATSUM-Material energies

4)SLEOUT-Sliding interface energies.

-the same animation frequency has been applied for these keyword too.

-Model check:-

After assigning all the keyword check the model using the model checker and make sure that the file is error file.

After that save the file as a".k" format.

-Run the file in the solver. if it's end as a normal termination then model is correct.

8) post-processing:-

-Animation of vonmises stress:-

-For that go to this way:-

post>Fringe component>stress>von mises stress

*The final frame of the vonmises sress:-

-The Vonmises stress at final frame is 2.272e-2 Gpa

*The plot of SLEOUT data vs time:-

-ASCII>sleout>load>select master energy & slave energy>prd

-Master energy is zero for all simulation, but slave energy are vary rapidly change for short time, This value is 0.734 j and that is same as that of sliding energy.

*Conclusion:-

-All the keywords has been created right from scratch & model checked.

-The purpose of this model is understand overall idea about basic keywords use of LSDYNA and running the simulation.