04 - Von Mises and utilisation2D Frame model

A 2 m UB 254 x 146 x 31 cantilever with a load at its tip, where the moment and the shear both peak at the fixed end. At 50 kN the extreme fibres reach 285 MPa; at 65 kN they would be at 371 MPa, past the 355 MPa yield strength, though still inside the section's plastic reserve. The von Mises stress sqrt(sigma^2 + 3 tau^2) combines normal and shear stress, utilisation U = sigma_vM / fy compares it with yield, and U* shows only the fibres beyond it.