Back to Statics Of Rigid Bodies repository
Analysis of trusses2D

Zero-force members

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

Open the complete lesson
Interactive engineering simulation

Zero-Force-Member Detector

Apply the two inspection rules before revealing the solver classification.

Rigid-body statics
explore task
Inspect unloaded joints first. Look for two non-collinear members or three members with two collinear.
AB: 53.3 T kNAB 53.3 TBC: 53.3 T kNBC 53.3 TAD: 66.7 C kNAD 66.7 CDC: 66.7 C kNDC 66.7 CBD: 0 kNBD 0Select joint AASelect joint BBSelect joint CCSelect joint DD80 kNA-Ry: 40.0 kNC-R: 40.0 kN
Joint load
80 kN
kN
10180

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

Detected zero-force members
BD

At unloaded joint B, BD is non-collinear with the other two members and is zero-force.

Max joint residual
0.00e+0
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.