how to apply torque or prestress in bolt

Saravanamoorthy,

You don't need Simulation; this is a question best answered by hand calculations and testing. You need to know, experimentally measure, or estimate the friction coefficient(s) between your bolt, nut and the parts being assembled. That will allow you to calculate the tension needed in the bolts and the torque needed to produce that tension. It will typically not be a very accurate calculation, as the friction coefficients typically vary a lot in real life.

Jerry S.

How do you define what torque is necessary ?