Question: Can you please clarify what is the advisable meshing size of plates.. Is there any limitations on the sizing..
Answer:
There is no such rule to determine the exact meshing size for which the deflection value will converge to realistic value ,but rather it completely depends on the type of structure and the loading applied on it.
You may first perform two trials and check the degree of variation of deflection results.
If the variation seems too large and unacceptable then you should go for finer meshing till you get some acceptable difference.
The deflection value always tends to approach the realistic value. The finer is the meshsize , more precise will be the result.
So, you have to judge the weightage and extent of precision your structure needs as far as deflection is concerned.