Analysis of trusses2D
Stability and determinacy
Use joints, sections, geometric rules, rank checks, and moving-load envelopes for determinate trusses.
Open the complete lessonInteractive engineering simulation
Truss Stability and Determinacy
Compare force-counting with equilibrium-matrix rank using valid, unique-member geometries.
Count + rank
m + r − 2j
0
Matrix rank
10 of 10 equilibrium rows
Interpreted condition
stable determinate
Why counting is insufficient: a zero count does not guarantee stable geometry, and a positive count does not prevent a rank-deficient mechanism.
Model scope and verification
Use the displayed units and idealizations, then verify the governing balance or compatibility equation before interpreting the result.