Hi Lukas, Sorry, I gave you the wrong function name (GetF returns the value of the preload in a ChLinkForce, something that is not set for a ChLinkBushing). The correct function to use is ChLinkForce::GetForce, but that one is cumbersome to use as it takes some arguments (you can access the required values, but that’s not a good API).
So, I added two functions ChLinkBushing::GetForce and ChLinkBushing::GetTorque which directly return the quantities you want. (Note that I cleaned up a bit the ChLinkBushing class and that resulted in a change to the enum used to specicy the type of bushing (Mount or Spherical) – see the updated demo) --Radu From: [email protected] <[email protected]> On Behalf Of Lukas K Sent: Wednesday, June 28, 2023 12:54 AM To: ProjectChrono <[email protected]> Subject: Re: [chrono] Bushing reaction forces Thanks for guidance and explanations. I ran demo_MBS_link_bushing.cpp with example 4 which uses ChLinkBushing. Then I used bushing_link->GetForce_X().GetF() to extract reaction forces but still getting zeroes. Where I'm making a mistake? wtorek, 27 czerwca 2023 o 08:34:51 UTC+2 Radu Serban napisał(a): Lukas, When using ChLinkBushing, you need to access the various individual ChLinkForce objects, using ChLinkLock::GetForceX(), ChLinkLock::GetForceY(), etc. (see https://api.projectchrono.org/classchrono_1_1_ch_link_lock.html ) and then invoke the GetF() method on each one (see https://api.projectchrono.org/classchrono_1_1_ch_link_force.html). I realize that this is a bit too convoluted, so I will add a ChLinkBushing functions to directly return the bushing force and torque. As a side note, ChLinkBushing is implemented as a “free” joint with internal forces on the 6 DOFs, so it is no surprise that Get_react_force() returns all zeros (there are no constraints). For ChLoadBodyBodyBushingGeneric, use ChLoadBodyBody::GetForce() and ChLoadBodyBody::GetTorque() (see https://api.projectchrono.org/classchrono_1_1_ch_load_body_body.html). --Radu From: [email protected] <[email protected]> On Behalf Of Lukas K Sent: Tuesday, June 27, 2023 12:37 AM To: ProjectChrono <[email protected]> Subject: [chrono] Bushing reaction forces What is the way to get reaction forces from bushing for: 1. ChLinkBushing 2. ChLoadBodyBodyBushingGeneric When I use Get_react_force() I get only zeroes -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/c70dc292-4f6b-478d-a34e-268c16a3d79fn%40googlegroups.com<https://groups.google.com/d/msgid/projectchrono/c70dc292-4f6b-478d-a34e-268c16a3d79fn%40googlegroups.com?utm_medium=email&utm_source=footer>. -- 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 [email protected]<mailto:[email protected]>. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/c55bd0bf-4831-4ced-b02e-1273add587dan%40googlegroups.com<https://groups.google.com/d/msgid/projectchrono/c55bd0bf-4831-4ced-b02e-1273add587dan%40googlegroups.com?utm_medium=email&utm_source=footer>. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/PH0PR06MB8237E0B651C791E646C03934A725A%40PH0PR06MB8237.namprd06.prod.outlook.com.
