It depends on the mesh you are using. Anyway in real aggregates it is common to see stress/strain concentrations... see for example here https://www.researchgate.net/publication/315590349_Finite_element_simulation_of_single_crystal_and_polycrystalline_Haynes_230_specimens

Article Finite element simulation of single crystal and polycrystall...

Hello my friend,

My understanding about this problem is probably the element where stress peak occured has been crushed between the neighbor elements. This situation could be caused by mesh distortion.

Hello Prithivirajan Veerappan,

The frequent causes of high stresses and incorrect distortions are due to the non-reading of the transition from elastic to plastic in the materials. It would be good to carry out real experiments when possible and to take into account their simulation behavior. Then the values obtained from the simulations approximate most often to the real experimental data. Another approach is to take the results from the curves of stiffness in plastic deformation from literary data or experiments from other authors involved in the field.

With respect

Emil Yankov

Dear Veerappan,

There could be two possible reasons:

1: Linear finite elements (you have already mentioned this in your question)

2: Very low element "volume" compared to the rest of the elements. These types of errors usually occur when you have a fine irregular mesh, and stresses or other constitutive equation variables concentrate on these elements.

Best regards,

Harris

Thanks, you are right. Some more details :

https://www.researchgate.net/post/How_does_a_highly_distorted_element_affect_the_results_of_FEA_displacement_strains_and_stresses_in_a_mathematical_sense