Not really.. I had kind of error there. It's still often toughness when you wish to study how material reacts to sudden increases in (kinetic)energy. Fracture

Not really.. I had kind of error there. It's still often toughness when you wish to study how material reacts to sudden increases in (kinetic)energy. Fracture toughness describes relation between maximum tension and maximum depth of pre-existing crack that still doesn't launch phenomena called "fast fracture". https://en.wikipedia.org/wiki/Fast_fracture https://en.wikipedia.org/wiki/Fast_fracture It's highly relevant in many cases, because most real world materials have microscopic cracks. And because the load where fast fracture might happen is often lot smaller than yield load. Curiously Charpy impact test still indicates more toughness than fast fracture. But it's never used to quantify toughness in real life. https://en.wikipedia.org/wiki/Charpy_impact_test https://en.wikipedia.org/wiki/Charpy_impact_test Thanks for that comment. I need to clear this stuff bit more in my head.