Plane Frame Analysis Back EN | ZH
FEM / Stiffness Method

Plane Frame Analysis — Direct Stiffness Method

Analyze portal frames using the direct stiffness method. Real-time deformed shape, bending moment diagrams, and member forces including lateral sway.

Parameters
Support Conditions
Span L 6.0 m
Column Height h 4.0 m
EI_beam (kN·m²) 10000
EI_column (kN·m²) 10000
Beam UDL w 20.0 kN/m
Lateral Load H (left→right) 0.0 kN

Stiffness Method

Beam element stiffness (local coords):

$$[k_e] = \frac{EI}{L^3}\begin{bmatrix}12 & 6L \\ 6L & 4L^2\end{bmatrix}$$

Global system: $\mathbf{K}\mathbf{U}=\mathbf{F}$

Max Displacement δ (mm)
Max Beam Moment (kN·m)
Max Column Moment (kN·m)
Sway Ratio δ/h