Sassanid leverage artillery ?

[deBeauharnais]

I think the drawing is a little too imprecise to tell if the crew look like Arabs. The man on the left seems to have clear hair, but this can be an imprecision caused by the modern artist.
Also, I can't see why the structure of this early trebuchet should look chinese. What part are you referring to ?
However, connection (direct or indirect) between chinese and sassanids seems possible.