Learning Forum

[JN_SE]

I'm working with a model of a car with 4 suspension system in rigid dynamincs and I need to specify a load that indicate the minimun load to start the compression of the spring, this is because the spring-damper system (shock Marzocchi Moto C2R) of the real vehicle has the property to select this number. For example, If I want to specify that the shock start the travel of compression after the driver sits in the car, I have to configure this value in the shock including the load of the sprung mass and the pilot (the quantity of load that affects that wheel), if the load in that wheel is 1000 [N] and the proportion of the load of the driver is 200 [N], I will adjust this value at 1200 [N], and the shock will not compress, but if the car pass throght a bump and the load increases the shock will start to compress.

Thanks!

[peteroznewman]

There is a Preload line in the Details window on a Longitudinal Spring.

[JN_SE]

The preload acts only in the initial state of the analysis, is just an initial condition.

[peteroznewman]

Put a COMBIN40 spring in parallel with the COMBIN14 spring that Mechanical created.
Configure the COMBIN40 spring to act as a hook as described in this thread:
/forum/discussion/1110/how-do-i-implement-combin40-for-springs-in-wb
The GAP capability of the COMBIN40 element will hold the preload between nodes I and J.
When the force between nodes I and J exceeds the preload the spring will compress more and the GAP will open.
When the force between nodes I and J goes below the preload, the force will become zero because the GAP will close and hold the preload force like a hook.

[JN_SE]

Hi Peter I 'd been trying to make it work with the code that you write in the link above, I created a simple model in rigid dynamics in WB (picture attached) but it doesn┬┤t work. I defined a longitudinal spring, apply a remote force in the mobile body and only liberate the movement in Y direction.
The code that I used in Commands is (Target: Mechanical APDL):
et,_sid,combin40
Keyopt,_sid,3,2 (I put '2' because the movement is in Y direction, is that right?...)
K1=50000
K2=100
C=0
GAP=0
FSLIDE=1500
r,_sid,K1,K2,C,GAP,FSLIDE
(I put K1=50000 because I want that it works as a rigid body...)