Moments in Contacts

Hi, the moment reported by contact forces in Adams Post arise from the moment arm between geometry reference marker (PSMARKER or Corner Marker) and point of contact. Adams just reports r X F where r is measured from the reference marker which is corner marker for primitive geometry or PSmarker for imported CAD geometry. For a system with no rotational constraint, the torque is still relevant because it will influence its rotational motion.

Hi Prerak, thanks for the explanation. I understand that torque may get generated in actual scenario as 3D surfaces come in contact. But the torque value calculation in that case is complex because deciding a common point to calculate moment arm is difficult. In ADAMS's case, as you mentioned, the moment arm is measured from PSMARKER or Corner Marker. It implies that point of application of those torques is the same marker. Does that mean when I am extracting contact loads for further use (For durability analysis), I should extract forces as well as moments at PSMARKER or Corner Marker? Also, do I need to consider these torques as a genuine output of the contact interaction?

Hi Prerak, thanks for the explanation. I understand that torque may get generated in actual scenario as 3D surfaces come in contact. But the torque value calculation in that case is complex because deciding a common point to calculate moment arm is difficult. In ADAMS's case, as you mentioned, the moment arm is measured from PSMARKER or Corner Marker. It implies that point of application of those torques is the same marker. Does that mean when I am extracting contact loads for further use (For durability analysis), I should extract forces as well as moments at PSMARKER or Corner Marker? Also, do I need to consider these torques as a genuine output of the contact interaction?

Yes, you can apply the moments at the PSmarker or corner marker for durability analysis. However, Adams loads export already gives out inertia forces which accounts for acceleration & moments due to contact force, contact incident cite location (s), reaction force(s) and moment(s) from constraints. This feature is accessible at File << FEA Loads Export in AVIEW and ACAR. You may want to consult Nastran quick reference guide regarding RFORCE and GRAV that outputs the inertia forces for rigid or flexible bodies in the Nastran or other requested formats. There is a macro available to transform the torque from one location to some other location. Please refer to the following SimCompanion article:

https://simcompanion.hexagon.com/customers/s/article/Contact-torque-relative-to-an-arbitrary-marker