Product Design of a Grenade Keychain by me. Design, FEA, Manufacturing (3d Printing) and Physical Testing.

This is my own Copyrighted Design of  grenade keyring project's prototype which is developed by me alone just for fun, It is opaque and illuminates in light source, if kept inside....well its tough durable grenade model to be used as keyring. It is made up of abs plastic. But it's still a prototype. It can be manufactured in various colours and materials too like plastics or Metals. I have its prototype made up of white ABS plastic manufactured by FDM 3d printing process. It has mass of 13.85 grams, and height of 5.94 cm. It has max diameter (grenade body) of 4.01 cm.

Properties of ABS as follows , Density = 1040 kg per meter cube.  Yield Strength = 41 Mpa and Ultimate Strength = 44 Mpa.

So, The project details are as follows:-  

I've Modelled this Grenade keychain in SolidWorks Software and rendering in Keyshot, Manufactured using 3d Printer FDM. 

So Now let's talk about FEA and Physical Testing

 1. CAP safety Test

In this test under gravity I've determined the maximum safe displacement and Force that cap can withstand.

Results are as follows Using  software Ansys workbench 2019 R1

Force applied = 16 N

Max safe displacement we get = 3.9 mm at FOS 1.125

Max Principal stress at cap = 37Mpa

Max equivalent stress = 36 Mpa 

More than 16 N pulling Force will result in Fracture or failure of the cap. (Explicit Dynamics)

Here is the correlation between Simulation Results and Physical Testing = Almost same or exact.

2. Grenade Keychain Drop Down Test

So i did it in Ansys with different heights and orientation under gravity where it is most likely to be failed, and also the Physical testing in parallel.

Results are as Follows

After dropping from height of 5.5 ft it will break as follows 

Meanwhile it's not safe in critical orientation in 3ft even ....

Although it's safe up to height of 4ft in Physical drop test but it may fail if it crashes in critical orientation even at the height of 3ft some what lower.

Summary:-

Rest all it is tough grenade to survive drop of 6ft even but, the only fragile part is the cap, which have to be revised further for the safe drop. So it's a nice keychain but not safe to drop tests as a result it may or may not fail depends upon orientations and your luck haha....., Mission Aborted ...Next time 😢 .

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 2.5 India License.