Considering the application I'd urge you to talk to your VAR about getting some training in Non-linear analysis, and also ask your VAR if they have any contacts that could help you properly design, perform, and interpret this simulation.
End time is the end time of the simulation, assuming your Start Time is 0 then the end time is the length of time you want to run the simulation for; real world time, your simulation will of course take longer than 1s to calculate. So in your example you are analysing the application of your load on that barrier from 0s to 1s.
x and y are non-dimensional. x is time (according to the units you're using) and y is a multiplier of the force constraint you add. So in your example there will be 0*75000N at Time=0, which ramps up linearly to 1*75000 at Time=4. As you have made your End Time 1s, you will never apply the full load.
You need to think about what you're analysing and decide how long the simulation should run for (by specifying the End Time) and apply your load within that time i.e. in your case you should either specify your End Time as at least 4s, or your graph of the load application should go from time 0 to 1.
Your material will not suffer from fatigue, but it could of course fail. The most relevant metric for you in your case is the material strain. In the results look at the strain of your elements, find the max strain of any of the elements during the simulation, if any of them are higher than the failure strain of the material you're specifying then the material has broken. The max strain of the material is hopefully specified on the material data sheet of the material you're going to make this barrier with.
Thank you for your answer
As per you told , i am looking for maximum strain of material. i have got some test reports for material , in which given data is
yield point - 363 n/mm2
tensile strength - 484 n/mm2
elongation - 36%
my model is showing
maximum stress (von mises)- 2508 n/mm2
displacement - 17mm
strain (ESTRN)- 0.006
(i have applied 75,000N and set end time as 1 second)
Based on this information, is it possible to find when will material face fatigue or break?
Please guide me.