Dear All,
I am working on a wooden rail sleeper analysis.
Using the Druker Prager model for Ballast and soils, Initially, I assumed the 2D Behavior of RailSleeper and Rails was Plane Stress and for Ballast and soil were Plane stress but I received Huge deflections in the model as you can see in figure 1.
Later I assumed everything in Plane stress and received very small deflection as you can see n figure 2.
Which one is suitable plane stress for the entire model or plain strain for soils/ballast and plane stress for a sleeper?
Kindly give suggestions, thank you.
Dear Naveen,
First of all understand the stress conditions in this type of problem, whenever the stresses in longitudinal direction is zero then treat the problem as plane stress conditions. In your case the stresses need not to be zero but strain is zero in the longitudinal direction that mean it is a plane strain problem. In reality it is 3-dimensional in nature but to reduce the computational time and easy to simulate the problem by depending upon the stress - strain conditions we treat the problem as plane stress, plane strain or axisymmetric conditions. In your case, the loading on the ballast is same up to a longer length and geometry is same along the entire length so the problem can be treated as plane strain. So, i suggest you to analyze the problem by assuming with plane strain conditions and verify all your material model & its properties to get correct results. ok all the best in your research..
Also, be careful about value of load on the rail, since the plane strain model implies uniform loading in longitudinal direction.
In my opinion, the plane strain condition should be considered for the problem you stated in your question.
Dear all,
Many thanks for your suggestions, should I consider an entire model in-plane strain?
You can consider plane strain model as a first (maybe very crude) approximation of the actual 3-d stress-strain state.
Dear Naveen,
You can consider the stress - strain response for ballast in Plane strain condition and for sleeper may be considered as 3-d problem. ok all the best in your research..
Dear Naveen Maddela
You can consider the stress - strain response for ballast in Plane strain condition and for sleeper may be considered as 3-d problem. ok all the best in your research. First of all understand the stress conditions in this type of problem, whenever the stresses in longitudinal direction is zero then treat the problem as plane stress conditions. In your case the stresses need not to be zero but strain is zero in the longitudinal direction that mean it is a plane strain problem. In reality it is 3-dimensional in nature but to reduce the computational time and easy to simulate the problem by depending upon the stress - strain conditions we treat the problem as plane stress, plane strain or axisymmetric conditions. In your case, the loading on the ballast is same up to a longer length and geometry is same along the entire length so the problem can be treated as plane strain. So, i suggest you to analyze the problem by assuming with plane strain conditions and verify all your material model & its properties to get correct results. ok all the best in your research..
I am not familiar with this model, but my expertise is in real railway track. I would definately go with the Plane strain view as nearest to what happens in reality!
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