Structural fracture mechanics is a way of understanding how structures (like bridges or airplanes) break or fail. It looks at what makes something strong and why it might fail. When a structure is being designed, engineers use structural fracture mechanics to test how it will stand up to different forces, like wind or earthquakes. They look at the materials it is made out of and how they fit together, as well as how strong the structure is overall, so they can make sure it is safe when it's finished.