Unit of the Torsional Stiffness

[xuanq...@gmail.com]

Hi all,

I use the following codes to build a torsion spring in Chrono. 

 auto revoluteJoint1 = std::make_shared<ChLinkLockRevolute>();
 revoluteJoint1->Initialize(beam1, floorBody, ChCoordsys<>(ChVector<>(10, -3.6, -4.3), q1));
 ChLinkForce *force = new ChLinkForce;
 force->Set_active(1);
 force->Set_K(20 ); ///< stiffness of the dof
 force->Set_R(0.5); ///< damping of the dof
 revoluteJoint1->SetForce_R(force);///< the torque acting about rotation axis
 mphysicalSystem.AddLink(revoluteJoint1);

So, what's the unit of the torsional stiffness 'K' ?

Is N*m/rad or N*m/dergree or other versions? 

In addition, I use  (kg, m, s)  in Chrono. 

Thanks,

Qihan

[Alessandro Tasora]

hi Qihan,

torsional stiffness is in N*m/rad.

In general, degrees are never used in Chrono (except when explicitly said in the comment to API function) and rads are used for rotations. Same for angular velocity: rads /s .

For the rest, yes, mass=kg, lengths=m, time=s. (anyway Chrono is dimension-less so you could assume, for example, that your lengths=mm or inches, but at this point also forces, gravity,  etc. must be expressed accordingly.)

Alessandro Tasora

--
You received this message because you are subscribed to the Google Groups "ProjectChrono" group.
To unsubscribe from this group and stop receiving emails from it, send an email to projectchron...@googlegroups.com.
To post to this group, send email to projec...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[xuanq...@gmail.com]

I've got it. Thanks!