If possible could you guide me through getting the results for Wooden Railsleeper design?
I am feeling more depression with this topic, please guide me sir to complete this thesis.
Below text is from my Professor.
I would suggest do start with a 2D-model. For timber linear elastic, anisotropic material behaviour is for my opinion satisfying, as the timber member would not come to a fracture state at serviceability loads. Modelling the ballast will be the most challenging part, you have to understand some geotechnical material models.
Pleas search in citavi for “hardening soil model (HS-model)” and “hardening soil with small strains (HSS-model)”. Ansys is unable to capture those material models.
But please understand the difference between the Mohr Coulomb MC and the improved HS and HSS-models for soils. The stiffness depends on the stress state and MC cannot capture that.
Try to find some literature where the combination sleeper-ballast was modelled using ANSYS.
I can remember some literature, where the ballast was modelled using Drucker-Prager or MC. Those models are implemented in ansys.
Find out the limitations of that models and a suitable way to overcome that limitations. I suggest to model the ballast twice, with upper and lower bounds of the stiffness.
The more the ballast is compacted, the stiffer the soil is. Also keep in mind timber creeping effects.
So you will have two models. First model at t=0 (initial state) and a second model at t=∞ (end state) including a reduced modulus of elasticity of wood (a simple way to take into account creeping of wood) and an increased stiffness of the ballast due to compaction.
After verification of your 2D model to available literature I would suggest to create a 3D model. Please also consider the necessary model length in track axis