How is safe working stress determined?

The safe working stress is determined by dividing the ultimate stress by the factor of safety. This method is grounded in engineering principles that aim to ensure safety and reliability in structures and mechanical components.

Ultimate stress is the maximum stress that a material can withstand before failure occurs. However, operating a system or component at ultimate stress would be unsafe due to the unpredictable nature of loads, defects, and variances in material properties. Therefore, engineers employ a factor of safety—a multiplier that accounts for uncertainties—when calculating safe working stress.

By dividing the ultimate stress by the factor of safety, engineers establish a limit for the stress that can be safely sustained under normal operating conditions, effectively reducing the risk of failure and ensuring that structures and machinery are robust enough to handle unexpected loads and conditions over time. This approach is a foundational principle in material science and structural engineering, emphasizing safety in design and operation.