Today, in designMargin of Safety Here is a note about the
Sometimes customers may ask for the "Margin of Safety" (MS) for the systems we design. I will make a note of how to interpret it and how to calculate it.
What is MS (Margin of Safety)?
What is Margin of Safety (MS)?Safety marginIt means.
This is,In an environment of extremely high certainty, if MS is 0 or greater, it can be said to be safe. It is.
Safety factor and margin are different.
Safety factorWhat is,The ratio of the minimum load that causes system failure to the maximum predicted system load. It is.
For example, if a component's load capacity is 100, and you apply a force of 100, the "safety factor" becomes 1, which is considered to not take safety into account.
Margin is sometimes used as a synonym for safety factor, butThe remaining part after subtracting "1" from the safety factor is called the margin.
Therefore, while margin may be used synonymously with safety factor, they are entirely different concepts.
How to calculate Margin of Safety (MOS)
MS = Ultimate Design Load / Expected Maximum Load - 1 > 0
Ultimate Design Load = Predicted Maximum Load × Safety Factor (approximately 1 to 1.2, depending on the situation)
Why was a safety factor necessary in the first place?
What is the safety factor set during design?What is set due to the existence of uncertainty in strength and uncertainty in loadIn design,The greater the "uncertainty" involved, the larger the safety factor (how many times) needs to be taken.(Uncertainty refers to the lack of certainty regarding the aging of materials, environmental differences, or unexpected usage.)
Therefore,Objects with a high safety factor (high risk) tend to have exaggerated designs. It is a
Also,The safety factor is set for elements with a high degree of risk in the system, so it does not necessarily mean high safety.However, generally, components that are directly related to human life often have larger safety factors. In certain categories, these may also be determined by law.
However,In fields like aerospace, the safety factor is set exceptionally low, around 1.2 times ± 5%.
This is in aerospace systems,Because safety equipment and redundancies directly translate to increased aircraft weight, leading to a decline in economic efficiencyThat's why.
This is possible due to thorough design, verification, and quality control, as well as the significant amount of time dedicated to maintenance.Reference: What are QT and AT level tests performed on space equipment?）
That's it.