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| """ | |
| Vibration / mechanical test standards corpus (vibration-only MVP). | |
| Curated from PUBLICLY AVAILABLE sources: | |
| - GEVS (GSFC-STD-7000) General Environmental Verification Standard | |
| - NASA-STD-7001 Payload Vibroacoustic Test Criteria | |
| - NASA-STD-7002 Payload Test Requirements | |
| - NASA-HDBK-7004 Force Limited Vibration Testing | |
| - NASA-HDBK-7005 Dynamic Environmental Criteria | |
| - MIL-STD-1540 Test Requirements for Space Vehicles | |
| - Launch vehicle payload user's guides (public PSD/SRS envelopes) | |
| These are simplified, representative knowledge chunks for an MVP RAG demo. | |
| Production should ingest the full standards text via document parsing. | |
| All generated output requires qualified test engineer review. | |
| """ | |
| VIBRATION_CHUNKS = [ | |
| { | |
| "id": "vib-levels-qual-accept", | |
| "source": "GEVS GSFC-STD-7000", | |
| "topic": "qualification vs acceptance vs protoflight levels and duration", | |
| "text": ( | |
| "Qualification random vibration is typically +3 dB above the Maximum " | |
| "Expected Flight Level (MEFL) for 120 seconds per axis. Acceptance is at " | |
| "MEFL for 60 seconds per axis. Protoflight applies qualification levels " | |
| "(+3 dB) but for the acceptance duration (60 s/axis). Tests are run in " | |
| "three orthogonal axes (X, Y, Z)." | |
| ), | |
| }, | |
| { | |
| "id": "vib-workmanship-psd", | |
| "source": "GEVS GSFC-STD-7000 Table 2.4-3", | |
| "topic": "component minimum workmanship random vibration qualification spectrum", | |
| "text": ( | |
| "Generalized component minimum workmanship random vibration qualification " | |
| "spectrum for components up to 22.7 kg (50 lb): " | |
| "20 Hz at 0.026 g^2/Hz; +3 dB/oct slope from 20 to 50 Hz; " | |
| "flat 0.16 g^2/Hz from 50 to 800 Hz; -3 dB/oct slope from 800 to 2000 Hz; " | |
| "2000 Hz at 0.026 g^2/Hz. Overall = 14.1 Grms. Acceptance level is 6 dB " | |
| "below qualification (flat region 0.04 g^2/Hz, 7.0 Grms)." | |
| ), | |
| }, | |
| { | |
| "id": "vib-mass-attenuation", | |
| "source": "GEVS GSFC-STD-7000", | |
| "topic": "mass attenuation of random vibration levels for heavier units", | |
| "text": ( | |
| "For components heavier than 22.7 kg (M in kg), the flat-region acceleration " | |
| "spectral density is reduced: ASD(M) = 0.16 * (22.7 / M) g^2/Hz, equivalent " | |
| "to a 10*log10(22.7/M) dB reduction, with the sloped breakpoints scaled " | |
| "accordingly. The reduction is capped so the spectrum never falls below the " | |
| "workmanship minimum. This prevents unrealistic overtesting of large units." | |
| ), | |
| }, | |
| { | |
| "id": "vib-grms-calc", | |
| "source": "Random vibration fundamentals", | |
| "topic": "how overall Grms is computed from a PSD", | |
| "text": ( | |
| "Overall Grms equals the square root of the area under the acceleration " | |
| "spectral density (ASD/PSD) curve across frequency. For a flat segment the " | |
| "area is ASD * bandwidth. For a sloped segment (constant dB/oct on a log-log " | |
| "plot) the area is computed analytically per segment and summed. Grms is the " | |
| "key single-number severity metric for a random vibration test." | |
| ), | |
| }, | |
| { | |
| "id": "vib-notching", | |
| "source": "NASA-HDBK-7004 / NASA-HDBK-7005 (force limited vibration)", | |
| "topic": "notching to prevent overtesting at resonances", | |
| "text": ( | |
| "Notching reduces the input acceleration spectral density at the test " | |
| "article's resonant frequencies so that responses or interface forces do not " | |
| "exceed realistic flight limits. Response-limited notching caps measured " | |
| "acceleration response; force-limited vibration (FLV) caps interface force " | |
| "using a semi-empirical force specification (the simple two-degree-of-freedom " | |
| "method sets a force limit constant C, commonly C^2 between 2 and 5). Notches " | |
| "must be justified by coupled-loads analysis or measured data and require test " | |
| "engineer approval; over-notching causes undertesting." | |
| ), | |
| }, | |
| { | |
| "id": "vib-sine-survey", | |
| "source": "GEVS GSFC-STD-7000", | |
| "topic": "low-level sine survey / signature and damage detection", | |
| "text": ( | |
| "A low-level sine sweep (signature survey, typically 0.25-0.5 g, 5-2000 Hz) " | |
| "is run before and after each random run to identify resonances and detect " | |
| "structural change. A primary-resonance frequency shift greater than about " | |
| "5 percent, or an amplitude change greater than about 20 percent, indicates " | |
| "possible damage and must be investigated." | |
| ), | |
| }, | |
| { | |
| "id": "vib-sine-qual", | |
| "source": "GEVS / launch vehicle user's guides", | |
| "topic": "sine vibration and quasi-static load verification", | |
| "text": ( | |
| "Swept-sine or sine-burst testing verifies the structure against low-frequency " | |
| "transient and quasi-static launch loads (typical quasi-static load factors " | |
| "are on the order of several to ~12 g axial/lateral depending on the launch " | |
| "vehicle). Sine sweep rate is commonly 2 or 4 octaves per minute. The launch " | |
| "vehicle payload user's guide provides the sine and quasi-static environment." | |
| ), | |
| }, | |
| { | |
| "id": "vib-shock", | |
| "source": "MIL-STD-1540 / NASA-STD-7003", | |
| "topic": "pyroshock / shock response spectrum", | |
| "text": ( | |
| "Shock requirements use a Shock Response Spectrum (SRS) from sources such as " | |
| "stage separation, fairing jettison, and pyrotechnic firing. Qualification " | |
| "SRS is typically +3 to +6 dB above the maximum predicted environment with " | |
| "2 actuations per axis. The launch vehicle user's guide provides the " | |
| "separation-event SRS at the payload interface." | |
| ), | |
| }, | |
| { | |
| "id": "vib-lv-environment", | |
| "source": "Launch vehicle Payload User's Guides (Falcon 9, Vulcan, Electron, etc.)", | |
| "topic": "launch-vehicle-specified random/acoustic environment drives the spec", | |
| "text": ( | |
| "The launch vehicle payload user's guide publishes the random vibration PSD, " | |
| "acoustic spectrum, shock SRS, sine environment, and quasi-static load factors " | |
| "at the payload interface, plus minimum structural frequency (stiffness) " | |
| "requirements to avoid coupling with vehicle modes (e.g. first axial/lateral " | |
| "modes above specified thresholds). The test specification envelopes the " | |
| "LV-specified environment with component workmanship minimums, then applies " | |
| "qualification margin and notching." | |
| ), | |
| }, | |
| { | |
| "id": "vib-control-tolerance", | |
| "source": "GEVS GSFC-STD-7000", | |
| "topic": "control tolerances and abort limits", | |
| "text": ( | |
| "Random vibration control tolerance is commonly +/-1.5 dB over most of the " | |
| "band and +/-3 dB at spectral peaks/edges, with overall Grms held within about " | |
| "+/-10 percent (-1/+3 dB typical). Abort limits (e.g. +6 dB) automatically stop " | |
| "the test to protect hardware. Control is via one or more accelerometers " | |
| "(single, average, or extremal control strategy)." | |
| ), | |
| }, | |
| { | |
| "id": "vib-passfail", | |
| "source": "GEVS GSFC-STD-7000", | |
| "topic": "pass/fail criteria", | |
| "text": ( | |
| "Pass criteria: (1) pre/post low-level sine signatures show no resonance shift " | |
| "beyond threshold; (2) functional/aliveness test passes after each axis; " | |
| "(3) visual inspection shows no damage, fastener backout, or fracture; " | |
| "(4) the control spectrum stayed within tolerance for the full duration. " | |
| "Any exceedance, signature change, or functional anomaly is a fail pending " | |
| "engineering disposition." | |
| ), | |
| }, | |
| ] | |