Plane stress or plane strain for Railway Ballast system ?
I am working on wooden railsleeper analysis.
Using Druker Prager model for Ballast and soils, Initially I assumed 2D Behavior of RailSleeper and Rails was Plane Stress and for Ballast and soil was Plane stress but I recieved Huge diflections in model as you can see in figure 1.
Later I assumed evrything in Plane stress and recieved very small deflection as you can see n figure 2.
Which one is suitable plane stress for entire model or plain strain for soils and ballst and plane stress for sleeper ?
Kindly give sugesstions, thank you.