hole in a plate

introduction :
in this challenge we compare the two plates which are subjected to tensile force ,and measure various parameters such as stress, strain and displacement using solid works this study gives us the idea about the stress concentration in the a material when subjected to load, so based on this i did some study on this stress concentration in the material
reference :
book vb bandari design of machine elments
explanation :
there is a similarity between velocity distribution of fluid flow in a channel and axially loaded plate thus a the fluid flow analogy is logical to understand the stress concentration .ie the stress is concentrated at the places where the cross-section of the plate drops ,this cause a excessive strain on the material so in order to distribute the stress throught the plate two holes are made parlelly thus the concentration of the stress is greatly reduces ,such type of changes means a lot paticularly when the material is subjected to fluctuating load this is because the stress at these concentrated spaces often more than the endurance stress
these stress concentration are measured by two method
(1)theoretical or finite element analysis of the model
(2)photo-elastic analysis of the epoxy model
fea is a mathematical way of doing it and the photo elastic analysis on the material is a experimental way of doing it which is often expensive, so we go with the fea method.
on designing a material which is ductile the stress concentration is not commonly considered for a static load .but the for fluctuating it very much important,in case of brittle materials like cast iron concentration factor should also be considered for both static and fluctuating load
some commonly used methods for reducing stress concentration
1)but giving multiple notches
2)drilling holes
3)giving fillet radius
4)removing unwanted material etc
results :

part1 (peak values)
stress=1.190x10^6 N/m^2
displacement=5.237x10^-4 mm
strain=4.271x10^-6
part2 (peak values)
stress=1.135x10^6 N/m^2
displacement=5.658x10^-4 mm
strain=4.105x10^-6

what we infer from this result is that there is a significant drop in peak stress value but this result in tiny decrement stiffness, which is shown in the displacement(from5.237x10^-4 mm to 5.658x10^-4 mm)