Method of sections

Use joints, sections, geometric rules, rank checks, and moving-load envelopes for determinate trusses.

Interactive engineering simulation

Choose a section cut and verify that the isolated truss half satisfies force and moment equilibrium.

Rigid-body statics

explore task

Select a cut crossing no more than three unknown members, then choose the simpler side for equilibrium.

Joint load80 kN

10–180

Drag for exploration or enter an exact value. Press Enter to apply; Escape restores the current value.

Truss height3.00 m

1.50–6.00

Drag for exploration or enter an exact value. Press Enter to apply; Escape restores the current value.

\sum F_x=0,\quad \sum F_y=0,\quad \sum M_O=0

Section equilibrium residual

0.00e+0 kN-equivalent

Cut members: AC, BC, BD. The highlighted forces act on the isolated side; the opposite half receives equal-and-opposite forces.

Max joint residual

1.42e-14

Assumption

Pinned, axial-only

Diagrams are schematic equilibrium models. Member lines do not show elastic deformation, buckling, connection flexibility, or second-order effects.

Model scope and verification

Use the displayed units and idealizations, then verify the governing balance or compatibility equation before interpreting the result.

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