As Dan suggested, the best way to get help on such issues is to provide a simple reproducible example.
Having said that, there are examples in Chrono where a preload is used on an RSDA. See for example the custom functors defined for tracked vehicle models (M113 suspension<https://github.com/projectchrono/chrono/blob/63e164907c468b290330282ca515dc3c0a0415ad/src/chrono_models/vehicle/m113/M113_Suspension.cpp#L43> and Marder suspension<https://github.com/projectchrono/chrono/blob/63e164907c468b290330282ca515dc3c0a0415ad/src/chrono_models/vehicle/marder/Marder_Suspension.cpp#L43>). We also provide various pre-defined TSDA and RSDA functor classes, some of which allow for inclusion of a preload, in ChForceFunctors.h<https://github.com/projectchrono/chrono/blob/main/src/chrono/utils/ChForceFunctors.h>. In any case, pay attention to the sign of the preload torque and make sure it is consistent with how the RSDA is defined (e.g., order of connected bodies). --Radu From: [email protected] <[email protected]> On Behalf Of M. Pereira Sent: Monday, May 18, 2026 11:27 AM To: ProjectChrono <[email protected]> Subject: [chrono] Detent Mechanism with ChRSDA issue Hi everyone, I’ve been using the ChLinkRSDA method to model the behavior of a detent mechanism in chrono. I added a preload torque so the mechanism has an initial resisting torque even before any external force is applied. However, after introducing the preload torque, the simulation became severely unstable. The moving part tends to separate or “break loose” from the pivot/frame connection during the simulation. Has anyone experienced similar instability issues when using RSDA? If so, how did you handle it? Also, I’d be interested to hear if anyone has modeled a detent mechanism using a different approach in Chrono that worked more reliably. I've been needing to reduce the timestep too much (to the power of -6) to make it a little more stable. Thanks in advance for any suggestions. -- 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 visit https://groups.google.com/d/msgid/projectchrono/89209ac1-ceb2-4af4-9a32-a4c3a6c8a6den%40googlegroups.com<https://urldefense.com/v3/__https:/groups.google.com/d/msgid/projectchrono/89209ac1-ceb2-4af4-9a32-a4c3a6c8a6den*40googlegroups.com?utm_medium=email&utm_source=footer__;JQ!!Mak6IKo!OlJpMaSl50enMb78y23z_HSMfoWEeyNM1f37NDMqxQByrGYoVjCEGJa9OIEeBQREOMqZATR2NULcKcru-UcFG_jH$>. -- 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 visit https://groups.google.com/d/msgid/projectchrono/CH3PPF46CDC21858D5E0039CE7FE6AE9906A7012%40CH3PPF46CDC2185.namprd06.prod.outlook.com.
