How to create FOS stress sensor from Simulation data?

How to create FOS stress sensor from Simulation data?

Hi all,

I am a bit new in using Soliworks Simulation. I want to create a sensor for a design study to optimize a part using factor of safety provision of simulation data. In simulation express it is already given as constraints, but when I try to create it in simulation premium, it doesnot works.  Basically what I am doing is

1. Creating a stress (maximum vonmises)  sensor using simulation data and checking factor of safety option
2. The newly created sensor gives me warning that data not available (could not understand as the material is applied and simulation study is already done/run)
3. Renaming sensor as FOS and using it as constraint in design study by setting sensor value > the minimum 1.5 (I want the minimum factor of safety to be kept as 1.5)
4. Strangely the optimization failes as the iteration shows only maximum von mises stress in each step rather than calculating Factor of safety in numbers

Please correct me where I am getting wrong in the above mentioned steps

Although I can specify a stress sensnor by calculating the value of maximum von mises stress equal to 1.5 FOS and give the constraint of sensor less than maximum that value but I wanted to have a Factor of Safety type sensor

I am an instructor and using Solidworks Education Premium Professional Edition 2011

Any help in this regard is highly appreciated!

Regards