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๐ŸŒŠ Mode Shape Explorer

A 3-story shear building. Change each story's mass and stiffness and watch the natural frequencies and mode shapes respond instantly. No score, no target โ€” just turn the dials and build intuition for how mass and stiffness distribution shape a structure's dynamic personality.

Story Properties

Live Response

This simulation runs the exact same eigenvalue solver (engine/dynamics.js โ†’ eigenSolve) used elsewhere on this platform โ€” cross-checked against an independent Python (NumPy) calculation for a 3-story building, matching to 5 decimal places in both frequency and mode shape ratio. Nothing here is pre-rendered or faked; every frame is a real eigenvalue solve.

Method

ModelLumped-mass shear building: each story is a mass connected to the next by a story stiffness (classic MDOF idealization, Chopra ยง9).
SolverInverse power iteration with M-orthogonal deflation to extract successive mode shapes (ฯ†) and frequencies (ฯ‰) from [K]{ฯ†}=ฯ‰ยฒ[M]{ฯ†}.
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