Ideas and thoughts about 12DOF suspension testrig modelling in Adams/Car

Colleagues,

 

I'm trying to model a testrig with operation similiar to 12DOF suspension testrig, where ALL wheel loads are attached to wheel hubs, for performing durability simulations close to real laboratory testing, and, also, load signals to use are based on data recorded by strain-gauge hubs. Default testrig, MDI_SUSPENSION_TESTRIG, doesn't seem to be suitable as it has only traction force attached to a wheel center, other forces and torques are attached to a contact patch.

 

My first idea was to exploit _wheel_forces template and perform General Actuation Analysis. It was quite easy to transform this template from 4-post to 2-post and revise directions of forces and torques. However, I stumbled upon a row of issues. For example, model response on vertical force in Actuation analysis differs from response during Dynamic simulation: with the equal suspension subsystems, knuckle displacement in Actuation analysis is bigger to bump side than the disp in Dynamic analysis (maybe, the reason is in absense of wheels and their masses). Next, for models with adjusting forces Static Analysis is performed for their alignment before the Dynamic, and Actuation Analysis starts without alignment.

 

In this case, I find possible (but not so reasonable) to edit MDI_SUSPENSION_TESTRIG and prepare macros with edited Suspension Dynamic Analysis, where all wheel loads are attached to a wheel hub in a wheel center or with some axis offset.

 

Maybe you have an experience of such way of durability simulation and can share your advice, or maybe you recommend to give it up and to work with load signals instead to achieve demanded wheel hub response.

 

Thank you in advance