EPFL School of Engineering’s Post

The hidden ligament that shapes how things break   In 2024, researchers in EPFL’s Laboratory of Engineering Mechanics of Soft Interfaces discovered that in brittle solids, complex cracks require more energy to advance than simple ones – a fundamental finding with implications for materials testing and development.    Now, the team has published another study that reveals the physics behind this discovery. New measurements of the 3D mechanics of crack propagation in brittle hydrogels show that instead of breaking cleanly apart, these materials split into a stepped shape, with two advancing crack fronts connected by a thin ligament.   By scanning a sheet of laser light through transparent hydrogels seeded with tracer particles, the researchers found that these ligaments concentrate a striking share of the energy released during fracture. In fact, a material's toughness scales directly with how much energy the ligaments store before they snap.    “Whenever something in daily life cracks or holds together – a windshield after a stone, a filling in a tooth, the gel in a contact lens – a ligament like this one is part of the story, and now we can finally see it,” the researchers say.   ➡️ Read the full paper, now published in Physical Review Letters 🔗 Falling through the Cracks: Energy Storage along Segmented Brittle Crack Fronts. https://lnkd.in/e4MGzWNp   ➡️ Read our news about the 2024 study published in Nature Physics 🔗 https://lnkd.in/e-Yg-c-H   John Kolinski | Xinyue Wei | #mechanicalengineering | #3Dimaging | #physics | #materials