Condition for selection of factor of safety
1. Effect of failure:
The factors of the safety is high in applications where failure of machine part may result in serious accident.2. Type of load:
Fs is low :- static external forces
Fs is high:-impact load
3. Degree of accuracy in force analysis
If forces acting on the machine component are precisely determined.
4. Material of component
Homogeneous material :- Low Fs
Non-homogeneous material :- High Fs
5. Reliability of components
Fs increases with increasing reliability
e.g. power station equipments, defence equipments.
6. Cost of component
High cost component :- High Fs
Low cost component :- Low Fs
7. Testing of machine element
When the machine component can be tested under Excel conditions of service :- low Fs
When it is not possible to test a machine part :- High Fs
8. Service conditions
Corrosive atmosphere, high temperature environment :- High Fs
9. Quality of manufacture
When quality of manufacture is high :- Low Fs
When quality of manufacture is poor :- High Fs
Note :-
Here Fs is stands for high factor of safety
Fs is high:-impact load
3. Degree of accuracy in force analysis
If forces acting on the machine component are precisely determined.
4. Material of component
Homogeneous material :- Low Fs
Non-homogeneous material :- High Fs
5. Reliability of components
Fs increases with increasing reliability
e.g. power station equipments, defence equipments.
6. Cost of component
High cost component :- High Fs
Low cost component :- Low Fs
7. Testing of machine element
When the machine component can be tested under Excel conditions of service :- low Fs
When it is not possible to test a machine part :- High Fs
8. Service conditions
Corrosive atmosphere, high temperature environment :- High Fs
9. Quality of manufacture
When quality of manufacture is high :- Low Fs
When quality of manufacture is poor :- High Fs
Note :-
Here Fs is stands for high factor of safety