A 30° rigid rotation read -13% strain — conjugate stress-strain pairs in large-strain shells
·8 min read
Rotation alone fabricates strain in the engineering measure, and a wrong stress-strain pairing shifts the internal work rate by 5% or 54%.
Thinner Means Stiffer — Shear Locking in Shell Elements and the MITC Tying Fix
·8 min read
A linear shell element gets stiffer, not weaker, as it thins out. The cause is one line: shear strain obtained by differentiating displacements.
Why Does the Bridge Sag Like That? The Direct Stiffness Method for Trusses
·5 min read
A bar with EA/L = 8e6 N/m moves 1.5 mm under 12 kN. The 12-member truss stays singular until four wall degrees of freedom are removed.