# How do they know how much a machine or building will last without having to wait for it before?

67 views
0

How do they know how much a machine or building will last without having to wait for it before?

In: Physics

People know a lot about how things break and why they break. You make a machine or building out of materials that break the way you want them to and do a bunch of math to estimate when it will happen. Then you normally (for machines) heat it up and run it really fast to make it break faster or (for buildings) put way too much weight on it so it breaks. Then you do a whole bunch more math to make sure the stuff broke when you thought it would.

Many times, they *do* just wait for something to break. Run a car engine at high RPM constantly for a month, and you’ll know if it fails after 740 hours of use. For a year, almost 9,000 hours.

However, as fun as that is, it isn’t always necessary. If my machine uses some kind of bearing, then I can use math to predict the life of that bearing. The same for most components – we simply already know how they fail, and have good mathematical models for it.