Research / Numerical methods

Lee frame (1968)

After Seng-Lip Lee, Francisco S. Manuel, Edwin C. Rossow, “Large Deflections and Stability of Elastic Frame”, Journal of the Engineering Mechanics Division (1968), doi:10.1061/JMCEA3.0000966.

Against the author’s code
Provisional reference
Against the paper’s figures
The pinned equilibrium path is shown in de Souza, Vanalli & de Luz (2020), §3.3, Figure 10, compared there with Schweizerhof & Wriggers (1986). The approximate first limit load of 1.83 kN is provisional: a precise numerical locator has not been verified. Figure 11’s 2.1474 kN refers to semirigid supports and is not used here.

Research, not a design tool. Nothing here is an engineering result.

A pinned L-frame traced through its first limit point with Stabileo’s production corotational arc-length solver.

First version · 0 reviews

Research, not a design tool.

One example

Two 120 cm legs, pinned at both ends, with a downward point load 24 cm from the corner. Twenty Euler–Bernoulli frame elements; E = 720 kN/cm², A = 6 cm², I = 2 cm⁴. Inputs use metres, kN and MPa. Elastic material, rigid corner, no shear deformation.

The spherical arc-length constraint follows equilibrium beyond the peak. Each displayed shape is the final state of a production-solver run ending at that step. This repeats work because the API returns only the last full displacement vector. No new solver is used.

Provisional reference

The pinned equilibrium path is shown in de Souza, Vanalli & de Luz (2020), §3.3, Figure 10, compared there with Schweizerhof & Wriggers (1986). The approximate first limit load of 1.83 kN is provisional: a precise numerical locator has not been verified. Figure 11’s 2.1474 kN refers to semirigid supports and is not used here.

de Souza, Vanalli & de Luz (2020), §3.3, Figure 10

Not yet

  • Verified numerical reference and digitized full reference curve
  • Mesh convergence and all later snap-back branches
  • Independent review or engineering certification

Cite this

Stabileo Research, “Lee frame (1968)”, reproduction of Seng-Lip Lee, Francisco S. Manuel, Edwin C. Rossow (1968), doi:10.1061/JMCEA3.0000966. Implementation: research/benchmarks/lee-frame-1968 at commit 8068cd16ea2c. Engine: the Stabileo engine at the same commit. Permanent links to this exact build are planned.