In Ansys, the safety factor is always shown between 15 and -15. My design shows both maximum and minimum value as 15 with overall red coloured model. Certain literature says that ansys is not capable of producing result if the safety factor is more than 15 and thus it shows like that. So could i confirm from the readings and the literature that my design is super safe?
In Machine Design and the calculations of other structures there exist so many safety factors. You have to be very carefull with the selection of the safety factor of your specific structure. You have to consider the kind of loads (static, dynamic etc.), how much certain you are about the way they are applied (if you say you apply 100 N is it really so much?, is it concentrated?, is it distributed ?, etc.) how well you know the material (is it a cheap material for which you do not know its real properties?) and how much safety the producer gives about its homogeneous structure? Please find the table of Service Factor of ISO and the way of its calculation. Now, if you use a safety factor of 15 in all of your calculations, you show that you do not know anything about the details of your structure, which in this way will be wrong-dimensioned. Most of the time the structure will be safe and expensive as overdimensioned but there will be one critical case that the structure will disappoint you.
In Machine Design and the calculations of other structures there exist so many safety factors. You have to be very carefull with the selection of the safety factor of your specific structure. You have to consider the kind of loads (static, dynamic etc.), how much certain you are about the way they are applied (if you say you apply 100 N is it really so much?, is it concentrated?, is it distributed ?, etc.) how well you know the material (is it a cheap material for which you do not know its real properties?) and how much safety the producer gives about its homogeneous structure? Please find the table of Service Factor of ISO and the way of its calculation. Now, if you use a safety factor of 15 in all of your calculations, you show that you do not know anything about the details of your structure, which in this way will be wrong-dimensioned. Most of the time the structure will be safe and expensive as overdimensioned but there will be one critical case that the structure will disappoint you.
Whenever the safety factor is too much high, at that time design is considered as poor. Because if your yield strength of material is suppose 1000 MPa and your allowable stress is 300 MPa then you could observe that safety factor is around 3.33 and design is safe. but still you could modify the design in such fashion that the safety factor should be optimized one. I suppose you can calculate safety factor manually rather then to relay on the ANSYS results.
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