Yoshimura buckling is a big science word that people use to describe what happens when something that is flat suddenly curves and makes waves. Imagine taking a long piece of paper and trying to fold it in half. If you press it one way, the paper might start to curve and make little waves. That's kind of like Yoshimura buckling.
This type of buckling is named after a scientist named Hideo Yoshimura who studied this phenomenon a lot. He found out that Yoshimura buckling can happen in all sorts of materials, like metal or plastic, but it's most likely to happen when the material is really thin or flat.
Yoshimura buckling can happen in all sorts of situations. For example, it might happen when a big, flat sheet of metal is being pressed and shaped into a car body. Or it might happen when a thin, flat sheet of plastic is being heated up and formed into a container.
When Yoshimura buckling happens, it can create a lot of problems. It might make the material weaker or more brittle, and it can change its shape in ways that are not wanted. Scientists and engineers are always trying to find ways to predict and prevent Yoshimura buckling so that they can make better, stronger, and more reliable products.