I want to simulate my 5 DOF robotic arm, in such a way that the calculated Torque and mass values of each joints (Servos) defined to be tested that are they capable of physically bear all the weight and are these defined torque would be perfect or not, is it all possible to simulate in MATLAB simmechanics
SimMechanics has two ways to drive a joint - by angle or by torque. You can give it a position or speed and SimMechanics will auto-calculate the torque required to achieve that setpoint, or you can provide the torque and SimMechanics will auto-calculate what the resulting position change will be.
You can simulate the system first by passing in the joint position references you'd like to have, and you can trend the joint torques and forces to see what size actuator you'd like to specify.
If, for example, you wind up with some torque profile that has a really short-duration peak that is much higher than you'd like to specify the motors for, then you can do a simple motor simulation by passing a torque reference and clamping that to whatever your motor's rated torque is. Performance will degrade some, as you then can't drive to the same peak torque, but the performance hit might not be noticeable.