Truss Simulator v2

Live demo: https://3uripides.github.io/truss-simulator-v2/

A browser-based truss simulator with a balsa wood strength check added. It is a personal recreation, built for learning, of the Truss Simulator from JHU Engineering Innovation. It is not affiliated with or endorsed by Johns Hopkins University, and the original is the authoritative tool.

Features

• Design: add nodes, members, forces and supports (pin, horizontal roller, vertical roller). Members, forces and supports can start on blank space (a node is created there).
• Move and select: drag nodes and force arrows, box-select several nodes and drag them together, Shift+click to add to the selection, Delete to remove.
• Delete: single node/member/force, forces only, a support only, or everything.
• Undo / redo: Ctrl+Z and Ctrl+Y (also buttons in the Design row).
• Double stacking: make any member two sticks side by side (shown bold, e.g. 3 x 3 mm becomes 3 x 6 mm).
• Solves member forces live with the method of joints; tension is blue, compression is red, reactions are green. A matrix view is in the Solve tab. A Color view button switches to a green-to-red stress view (how close each member is to failing).
• Balsa Wood tab: stick size, density, modulus, tensile and compressive strength, buckling factor and a glue/defect strength factor. Finds each member's limit (tension break, crushing or Euler buckling), the weakest member, and the estimated failure load in N and grams.
  • Test load slider: scale the applied load and watch the result update.
  • Animate load test: ramps the load until the first member breaks.
  • Where to put the load: failure load for a single weight at each node.
  • Parts list: cut list of stick lengths, counts, total length and weight.
• Import & Export: pre-built trusses, Download bridge (.json), Upload bridge, and Export image (.png).
• Autosave in the browser, dark mode, and a Guide dropdown (top right) that explains every feature.
• Display & Dimensions: units, window size, snap grid, zoom/pan, label toggles.

Limits of the balsa model

Pin-jointed truss, axial forces only. Bending, glue-joint shear and stick defects are not modeled, so the failure load is an upper bound. Test your real bridge. Pre-built trusses 2-4 are my own examples, not copies of the original's.

Run locally

Open index.html in a browser. No build step or dependencies.