Hello,
I was playing around with the Rotational Body Force load in Abaqus CAE 2025 and am confused by the direction of rotation. For a simple hollow cuboid test case, I am applying a rotary acceleration like this:
So a positive rotary acceleration about the z-axis.
However, when I look at the resulting body motion, it is experiencing a negative rotation about the z-axis. So my questions are:
- Am I misunderstanding the definition of axis of rotation via point 1 and 2?
- Is the direction of the rotary acceleration following the left-hand rule?
I am using a static step with inertia relief and derive the body motion from the IRA history output. For the above rotational body force I get a negative IRA3 component. Whereas if I apply a positive moment on the body via two force on each end (a positive force in y on force_point_1 coupled to the +x face and a negative force in y on force_point_2 coupled to the -x face), I get a positive IRAR3 result. This is the body showing all mentioned loads:
EDIT: also applying a positive concentrated moment about the cog (coupled to the whole body) results in a positive rotation about the z-axes (IRAR3)
