There is no one specific widely accepted single sign for "violence."
I notice that my interpreters (in the Sacramento, California region) tend to fingerspell DV to mean "domestic violence."
If I were to pick one sign that I see used most often to represent the general concept of "violence" it would be the sign for "terrible." (This is the sign I use.)
TERRIBLE:
Below I will show you some other signs that are commonly used to mean "violence."
The top three are "abuse, assault, and fight."
ABUSE
ASSAULT
FIGHT:
CRUEL
MEAN!
General "destruction" can be expressed via the sign for: DESTROY
DESTROY
Notes: