Fine. Than step by step 
Create new Damage Types (as many as you wish) https://i.imgur.com/9jWVf1h.png
Now a very “simplistic” weapon Switching System (you can use your own existing one) https://i.imgur.com/X2EkHEa.png
Simple Attack with a trace https://i.imgur.com/03Bxobr.png also set the default for Damage Type to the first equipped Weapon.
Moving on to our Crate first we create a handy reduce Health function that also gives a bit Debug info https://i.imgur.com/g9VLZ0d.png
We also setup our Current Health to max health at the Beginning and Implement the take any Damage event https://i.imgur.com/pao102J.png
The first case “Blunt Damage” I simply apply Damage as is.
In the next examples just to showcase how to handle other types of Damage there is Fire Damage that Spawns a Particle and applys Damage over Time. And the Last one does Double Damage and applys Physical Force based on the Damage causers Location (Could be a Granade, Simulation on the Crate needs to be on) https://i.imgur.com/bfStJ66.png
BluntDamage Screen capture - 5b87139969cafef4cb35b05c5921e8c7 - Gyazo
Fire Damage + couple blunt hits Screen capture - 579886f282ff70c6434a113534901409 - Gyazo
Explosion Damage Screen capture - 7d4ca0d8226f5f1c86c6a30bd0124928 - Gyazo
Simple as that and very Flexible and the best part is they work Completly independent of each other. Your Character can Hit anything and does not need to worry how the Damage gets applied and the reciving End does not Care from who or what it recives Damage and can Filter down anything you need to know.