Direct stiffness method · Truss FEM · Member force heatmap
E = 200 GPa, A = 0.01 m²
Interactive 2D truss bridge simulation using the direct stiffness method (FEM). Apply loads, watch deformation, and see member forces colour-coded from tension (blue) to compression (red).
The direct stiffness method assembles individual member stiffness matrices into a global system [K]{u} = {F}. Solving for displacements {u} gives member forces by computing strain from deformation.
Click nodes to apply loads. Watch the bridge deform (exaggerated for visibility). Each member is colour-coded: blue for tension, red for compression. Adjust the load magnitude and observe stress redistribution.
The Warren truss (equilateral triangles) was patented in 1848 by James Warren. Triangulation is key — unlike rectangles, triangles cannot deform without changing member lengths, making trusses inherently rigid.