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My random knot in the Web


This is my home in the virtual world, where I write about things that I want to share. The freely available software that I've written as well as some of the photographs I've taken over the years can also be found here. Please use the navigation links on the right if you are looking for something.

Recent articles

  1. Folded leaf spring ball joint flexure

    The Dutch-language engineering book “Constructieprincipes” by M.P. Koster contains flexure made out of four folded leaf springs that kind of acts like a ball joint.

    The point where the load is applied should rotate around a virtual center formed by the point where the fold lines meet. The goal of this article is to simulate that and see if it works.

  2. Corrugation against buckling

    Composite sandwich products loaded in bending tend to fail by buckling of the laminate under compression. The author’s intuition is that corrugating the surface under compression should help. So the question is; does it help, and how much. That is what will be investigated in this article.

  3. Hex versus tet meshes in FEA

    In this article the difference in the images of the stresses between a quadrilateral hexahedron (“hex”) mesh and a tetraeder (“tet”) mesh will be investigated. In both cases, second order elements will be used.

    Hopefully this will make it clear to the reader why hex meshes are generally preferred.

    The plate with a hole that was the subject of a previous article will again be used. The analyses will be done using CalculiX.

  4. The titan implosion

    TL;DR, this was a triumph of stupidity and greed over good engineering.

    Engineering design standards are often written in blood, in the sense that these standards often came into being after accidents involving serious loss of life. The CEO of Oceangate ignored them, apparently because they got in his way of saving costs. As it turns out, reality is not susceptible to CEO bullshit.

    Unsurprisingly, “move fast and break things” is not a good strategy when lives are at stake.

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