cymbal-bow-v1 is no longer a draft
3 changed files+2−3
README.mdmodified+1−1View file
@@ -7,7 +7,7 @@ This repository defines simulation challenges that approach a cymbal one feature
77 | ID | Title | Deliverable |
88 | --- | --- | --- |
99 | [cymbal-flat-disk-v1](challenges/cymbal-flat-disk-v1/README.md) | Flat bronze disk struck with a drum stick, geometrically nonlinear (Saint Venant-Kirchhoff): radiated pressure | 6 s mono wav, 48 kHz, float32 |
10-| [cymbal-bow-v1](challenges/cymbal-bow-v1/README.md) (draft) | The same disk bowed into a shallow paraboloid, 25 mm rise: the effect of curvature alone | 6 s mono wav, 48 kHz, float32 |
10+| [cymbal-bow-v1](challenges/cymbal-bow-v1/README.md) | The same disk bowed into a shallow paraboloid, 25 mm rise: the effect of curvature alone | 6 s mono wav, 48 kHz, float32 |
1111
1212 The starting point is the simplest object that can sound like a cymbal: a flat, free disk of bell bronze with the diameter and thickness of a 16 inch crash, uniformly thick, struck near the rim by a short stick-like force pulse and radiating to a listener above it through the Rayleigh integral. The material model is Saint Venant-Kirchhoff, so the strain is exact and the response geometrically nonlinear; the material remains elastic. This is the model of the plate tier's second challenge applied to a disk with a harder, shorter strike, and it produces the pitch glide and broadband cascade that distinguish a cymbal from a struck plate. Thin-plate theories (von Kármán with or without in-plane inertia) are approximations to this model, and their error relative to a converged three-dimensional solution includes the modeling error of plate theory. Until such a solution is submitted, the reference is the best thin-plate solution and the reported errors measure only differences within plate theory; the results page says which it is.
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challenges/cymbal-bow-v1/README.mdmodified+1−1View file
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11 # cymbal-bow-v1: bowed bronze disk struck with a drum stick, geometrically nonlinear
22
3-Draft: this specification is under discussion; its first solutions are being produced and the scale was fixed from them.
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55 This is the second challenge of the cymbal tier. It is [cymbal-flat-disk-v1](../cymbal-flat-disk-v1/README.md) with one change: the disk is no longer flat. Its mid-surface is a shallow paraboloid rising 25 mm from the rim to the center, the bow of a cymbal without its bell, and the thickness is uniform along the normal. Material, damping, strike, listener, output format and error measures are unchanged, so the difference between the two challenges is the effect of curvature alone. Curvature couples stretching and bending already in the linear regime, which raises the low modes and changes their radiation, and it adds quadratic terms to the nonlinearity, so the pitch glide and the cascade of the flat disk take a different form. The deliverable is again six seconds of pressure at the listener from the surface acceleration.
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challenges/cymbal-bow-v1/challenge.jsonmodified+0−1View file
@@ -2,7 +2,6 @@
22 "challenge_id": "cymbal-bow-v1",
33 "title": "Bowed bronze disk (paraboloidal shell) struck with a drum stick, geometrically nonlinear: radiated pressure",
44 "version": 1,
5- "status": "draft",
65 "output": {
76 "type": "wav",
87 "sample_rate_hz": 48000,