I am trying to simulate the full vehicle durability analysis using modal transient method for a LCV. I have the test track forces on BIW hard points in the vehicle loaded condition. But while performing the analysis in vehicle loaded condition, since i have added extra mass in the seats and cargo it leads to wrong modal frequncies and in turn gives incorrect results.
Can i perform the analysis using unloaded condition (untrimmed model without taking passenger and cargo mass) and applying loaded conditions loads??
Will the results obtained be correct?
simple answer: no!
The system answer depends on the load distribution, and your modal excitations will be different.
Especially for durability analysis the process of loads cascading may get delicate but is extremenly important. The amplitude of large excitations may get wrong by insufficient (non-linearities in bushings, etc.) modelling and lead to completely wrong durability results.
In a case like yours, I would highly recommend to do a joint method transfer project with us for a first project on such a topic.
Product Line Manager Durability Solutions