• Soil mechanics : Clays and sands don ’ t always rebound the way we ’ d like .
• Seismic engineering : Structures rely on hysteretic damping to absorb earthquake energy .
• Traffic signals ( metaphorically ): Ever noticed how red lights always seem longer than green ones ? That ’ s perceived hysteresis — okay , not real engineering , but still annoying .
In short , hysteresis is why engineers can ’ t just reverse the math and assume everything works the same forward and backward . Life — and physics — just isn ’ t that simple .
Engineering Term of the Month
Hysteresis might sound like a medical condition , but don ’ t worry — it won ’ t land you in the ER . Instead , it ’ s the fancy term for when a system doesn ’ t immediately snap back to its original state after being loaded . In civil engineering , we see hysteresis all over the place : from buildings swaying in an earthquake to soil behaving just a little differently on the way up than it did on the way down .
In simple terms , hysteresis is the lag between input and response . And in an engineer ’ s world , lag usually means extra forces to deal with .
A classic example of hysteresis is in structural damping — when a building sways in an earthquake , energy is absorbed and dissipated , causing a loop in the forcedisplacement relationship . If you ’ ve ever seen a graph that looks like a squiggly oval instead of a straight line , congrats ! You ’ ve met hysteresis .
Where else do we see it ?
Hysteresis
• Soil mechanics : Clays and sands don ’ t always rebound the way we ’ d like .
• Seismic engineering : Structures rely on hysteretic damping to absorb earthquake energy .
• Traffic signals ( metaphorically ): Ever noticed how red lights always seem longer than green ones ? That ’ s perceived hysteresis — okay , not real engineering , but still annoying .
In short , hysteresis is why engineers can ’ t just reverse the math and assume everything works the same forward and backward . Life — and physics — just isn ’ t that simple .