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Catégorie :Category: nCreator TI-Nspire
Auteur Author: golozer
Type : Classeur 3.0.1
Page(s) : 1
Taille Size: 2.97 Ko KB
Mis en ligne Uploaded: 28/03/2025 - 00:12:31
Uploadeur Uploader: golozer (Profil)
Téléchargements Downloads: 3
Visibilité Visibility: Archive publique
Shortlink : http://ti-pla.net/a4550905
Type : Classeur 3.0.1
Page(s) : 1
Taille Size: 2.97 Ko KB
Mis en ligne Uploaded: 28/03/2025 - 00:12:31
Uploadeur Uploader: golozer (Profil)
Téléchargements Downloads: 3
Visibilité Visibility: Archive publique
Shortlink : http://ti-pla.net/a4550905
Description
Fichier Nspire généré sur TI-Planet.org.
Compatible OS 3.0 et ultérieurs.
<<
=== RAMS-T === Reliability R(t): P(system works [0, t]) R(t) = e^(»t) MTBF = 1/», MTTR = 1/¼ Availability A(t) = MTBF / (MTBF + MTTR) Maintainability M(t) = P(repaired before t | failed at 0) Safety = Ability to avoid unacceptable events (prob × severity) Testability = Coverage, Detection rate, Localization rate === RISK CONCEPTS === Risk = Severity × Probability Criticality matrix No zero risk! risk is 2D: severity & likelihood Prevention: reduce probability Protection: reduce severity === ACCIDENT ROOT CAUSES === Examples: Challenger, Tchernobyl, Seveso, Ariane V, etc. Causes: Poor training, no feedback, ignored signals, bad crisis mgmt Complexity + bad org = systemic hazard === HIGH RELIABILITY ORG (HRO) === Encourage error reporting, no blame Experts lead during crisis Double-barriers: occurrence + severity Traceability, training, safety culture === QUANTITATIVE MODELING === Bathtub curve: early failures useful life wear MTBF = 1/»; R(t) = e^(»t); For MTBF=100h R(100)=0.37 Availability types: Di = MTBF / (MTBF + MTTR) Do = MUT / (MUT + MDT) === FUNCTIONAL ANALYSIS === External FA (Octopus): "What it does" Internal FA (Block Diagram): "How it works" Tools: Horned beast, Octopus, Block Diagrams, CdCF === SAFETY ANALYSIS METHODS === Inductive (Bottom-Up): - PRA (Preliminary Risk Analysis) - FMEA/FMECA (Failure Modes, Effects, Criticality) - ETA (Event Tree) Deductive (Top-Down): - FTA (Fault Tree Analysis) - CCD (Causes-Consequences Diagram) Other: - RBD (Reliability Block Diagram) - Markov chains (state transitions) - Petri nets (graphical + timing) - HAZOP (deviation analysis) === FAULT TREE NOTES === Minimal cut = causes of top event Success path = prevents top event Use Boolean logic for reduction === USE CASE EXAMPLES === Distress Beacons: R=0.999 » ~ 3.57e5 for 28h TGV A/C: MTBF=1500h »=6.7e4 Ship propulsion: 2/3 redundancy R = Rc × [3Rp²(1Rp) + Rp³] === SAFETY MANAGEMENT === Use the V-cycle: Define Allocate Evaluate Plan: Predict Build Maintain Capitalize (REX) Key: OS plan, Critical Point Handbook, RAMS studies === FINAL REMINDERS === Use R(t)=e^(»t), MTBF=1/», A(t)=MTBF/(MTBF+MTTR) Always assess risk pre-design Watch delta curve early poor safety scales to danger Use feedback & iterative improvement Made with nCreator - tiplanet.org
>>
Compatible OS 3.0 et ultérieurs.
<<
=== RAMS-T === Reliability R(t): P(system works [0, t]) R(t) = e^(»t) MTBF = 1/», MTTR = 1/¼ Availability A(t) = MTBF / (MTBF + MTTR) Maintainability M(t) = P(repaired before t | failed at 0) Safety = Ability to avoid unacceptable events (prob × severity) Testability = Coverage, Detection rate, Localization rate === RISK CONCEPTS === Risk = Severity × Probability Criticality matrix No zero risk! risk is 2D: severity & likelihood Prevention: reduce probability Protection: reduce severity === ACCIDENT ROOT CAUSES === Examples: Challenger, Tchernobyl, Seveso, Ariane V, etc. Causes: Poor training, no feedback, ignored signals, bad crisis mgmt Complexity + bad org = systemic hazard === HIGH RELIABILITY ORG (HRO) === Encourage error reporting, no blame Experts lead during crisis Double-barriers: occurrence + severity Traceability, training, safety culture === QUANTITATIVE MODELING === Bathtub curve: early failures useful life wear MTBF = 1/»; R(t) = e^(»t); For MTBF=100h R(100)=0.37 Availability types: Di = MTBF / (MTBF + MTTR) Do = MUT / (MUT + MDT) === FUNCTIONAL ANALYSIS === External FA (Octopus): "What it does" Internal FA (Block Diagram): "How it works" Tools: Horned beast, Octopus, Block Diagrams, CdCF === SAFETY ANALYSIS METHODS === Inductive (Bottom-Up): - PRA (Preliminary Risk Analysis) - FMEA/FMECA (Failure Modes, Effects, Criticality) - ETA (Event Tree) Deductive (Top-Down): - FTA (Fault Tree Analysis) - CCD (Causes-Consequences Diagram) Other: - RBD (Reliability Block Diagram) - Markov chains (state transitions) - Petri nets (graphical + timing) - HAZOP (deviation analysis) === FAULT TREE NOTES === Minimal cut = causes of top event Success path = prevents top event Use Boolean logic for reduction === USE CASE EXAMPLES === Distress Beacons: R=0.999 » ~ 3.57e5 for 28h TGV A/C: MTBF=1500h »=6.7e4 Ship propulsion: 2/3 redundancy R = Rc × [3Rp²(1Rp) + Rp³] === SAFETY MANAGEMENT === Use the V-cycle: Define Allocate Evaluate Plan: Predict Build Maintain Capitalize (REX) Key: OS plan, Critical Point Handbook, RAMS studies === FINAL REMINDERS === Use R(t)=e^(»t), MTBF=1/», A(t)=MTBF/(MTBF+MTTR) Always assess risk pre-design Watch delta curve early poor safety scales to danger Use feedback & iterative improvement Made with nCreator - tiplanet.org
>>
