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#solidmechanics — Public Fediverse posts

Live and recent posts from across the Fediverse tagged #solidmechanics, aggregated by home.social.

  1. Fluids Can Fracture

    Fracture is a sudden, brittle breaking-apart that we generally associate with solid materials that get stressed too far. Some viscoelastic, non-Newtonian fluids have been known to fracture, but that was generally thought to be unusual. But a recent study turns that idea on its head, revealing that even simple, albeit highly viscous, liquids can fracture.

    A viscous hydrocarbon fluid gets stretched at 100 mm/s, drawing it into a thinning shape.

    When you stretch a liquid, the general expectation is what you see above: the liquid gets drawn into an ever thinner shape. But researchers found that–when stretched quickly–that same simple hydrocarbon liquid cracked open:

    A viscous hydrocarbon fluid gets stretched at 300 mm/s, causing it to fracture like a solid.

    There’s even an audible snap, which you can hear in the video below. The results were so surprising that they repeated the experiment several times and with different viscous (but Newtonian) liquids. The results held. When the liquids were pulled to a critical stress, they audibly snapped and fractured like a solid.

    The next question, of course, is why this happens. The authors suspect (but have yet to show) that cavitation may be at play in the initiation of the crack that separates the liquid in two. (Image, video, and research credit: T. Lima et al.; via Gizmodo)

    https://www.youtube.com/watch?v=i5TQegTyCvc

    #fluidDynamics #fracture #newtonianFluids #physics #science #solidMechanics #viscousFlow
  2. Rolling Down Soft Surfaces

    Place a rigid ball on a hard vertical surface, and it will free fall. Stick a liquid drop there, and it will slide down. But researchers discovered that with a soft sphere and a soft surface, it’s possible to roll down a vertical wall. The effect requires just the right level of squishiness for both the wall and sphere, but when conditions are right, the 1-millimeter radius sphere rolls (with a little slipping) down the wall.

    Rolling requires torque, something that’s usually lacking on a vertical surface. But the team found that their soft spheres got the torque needed to roll from their asymmetric contact with the surface. More of the sphere contacted above its centerline than below it. The researchers compared the way the sphere contacted the surface to a crack opening (at the back of the sphere) and a crack closing (at the front of the sphere). That asymmetry creates just enough torque to roll the sphere slowly. The team hopes their discovery opens up new possibilities for soft robots to climb and descend vertical surfaces. (Image and research credit: S. Mitra et al.; via Gizmodo)

    #adhesion #fluidDynamics #physics #science #slip #softMatter #solidMechanics

  3. #SPHERIC2025 will be in #Barcelona
    spheric2025.upc.edu/

    It will be the first #SPHERIC #conference to break from the "classic" SPHERIC International Workshop format that was also employed for the SPHERIC 2022 I organized in Catania, and closer to other more traditional conferences (hence also the change in name, to SPHERIC World Conference).

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    #SPH #CFD #SolidMechanics #AstroPhysics #ParticleMethods