CFM Fan Platform

航空

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航空

February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1
Fan Platform
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2
Fan Platform
AFT Pin Loss
• A piece of a fan platform was liberated into the
fan flow on an engine having accumulated 3495
TSN, and 2069 CSN
• After engine shutdown, the platform piece, and
the AFT pin nut have been recovered inside the
engine
 The AFT pin not recovered
• The platform piece and nut were expertised
 Bushing was lost at shock with fan case
 Rupture of the platform was statis, no LCF
 The self locking fixture of the nut was per
specification
• The booster spool has been shipped to CFM for
expertise
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3
AFT Pin Loss
Non conformity Design concern
Pin
Assembly error Engine life
Pin
Nut
Platform
Bushing
Booster
lug
- Rupture
- Stretching
Pin-nut assembly
- Wrong assembly torque
- Loosening by vibrations
Platfo- rm microrotation
Assembly procedure Nut rupture
Booster
- Crushed area
- Thermal effect
- Interference with pin
Platform
- Platformrupture
- Bushing rupture
- Swaged design effect / non swaged
Wrong parts
- Pin
- Nut
- Non swaged bushing
Process
- Wrong tooling used :
air driven screw driver
- Wrong wrench used
- Bad lubrication
- Torque level
- Bad working
conditions
Particular events
- Ingestion
- Vibrations
Particular
actions
Very low probability
Low probability
High probability
Investigation
on going
Investigation
completed
Fan Platform
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4
Root Cause status
• Nut looseness
 Torque value is 21 N-m
 AFT pin and booster hole geometry tolerances (340-000-814-0/-815-0)
allow potential interference which would explain the looseness
 Process to torque the nut of the AFT pin is not easy
 Potential platform micro-rotation could be a contributor in the nut
liberation
AFT Pin Loss
Root cause not fully understood.
Waiting for Booster Spool Investigation.
Fan Platform
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Current Definitions Status
• Booster spool upgraded with counter-weights in Nov 2000
 Torque value increased to 27 N-m
 Better durability (lower de-torque stresses, less lug bending)
 Torque value applied on the pin
• Production improvement (340-000-816-0) introduced in Jul 2001
 New booster design with thicker lug
 AFT pin diameter increased and geometry optimized
 Torque value increased to 45 N-m
AFT Pin Loss
No Platform liberation concern with above
configurations
Fan Platform
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6
Field Containment Plan
• Implementation of booster spool counter-weights is effective at solving the
AFT pin nut looseness
• Inspection of platform AFT pin torque to be recommended at first
opportunity (fan blade relubrication)
 SB in review, expected to be released in Feb 2002
– One-time operation
– Torque at 21 N-m
AFT Pin Loss
Fan Platform
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Content
• Background
• Technical Status
• Design Improvement
• In-service Plan
Fan Platform
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 8
Background
• Initial configuration (340-001-805/806-0) since EIS :
 Concern with bushing migration
• Swaged bushing (340-001-809/810-0), since Oct 2000 :
 Implemented on all platform lugs
 Rework since Nov 2000
– 805 --> 810, and 806 --> 809
– SB 72-271 : Recommend to implement swaged
bushing at next shop visit when engine >
10,000CSN
• Basic material : anodized 7075 aluminum
• Minor interferences with disk and blades
• Cases of seal disbond
Fan Platform
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Technical Status
• Rig tests experience :
 4 middle lug ruptures encountered during rig tests :
– Parts representative of type designs : with and w/o swaged bushing
– Test representative of operating conditions (500 - 5,405 rpm)
 Cracks found during same tests on 3 sets (24 platform/set) after around
40,000 cycles on:
– Middle lug hole : 16 platforms cracked
– Forward lug hole : 1 platform cracked
– Aft lug hole : 1 platform cracked
– Ribs : 2 platforms cracked
Platform P/N Bushing Cycles at rupture Liberation
Event # 1 340-001-809-0 Swaged 42,657 Yes
Event # 2 340-001-806-0 Non-swaged 37,017 Yes
Event # 3 340-001-809-0 Swaged 40,108 Yes
Event # 4 340-001-809-0 Swaged 40,108 No
Fan Platform
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Technical Status
• Mechanical Analysis
 Part modelization :
– Finite Element Model are established
– Critical locations are well predicted
 Rig tests vs lab results on current middle
lug (809) life :
 Predicted - 3S life for non-swaged platform
(805/806) :
Lab analysis Predicted average Predicted -3S
Initiation 19000 19300 12700
Propagation 23000 19000 9500
Total life 42000 38000 26500
Initiation site
Predicted -3S
Initiation 10000
Propagation 8500
Total life 21400
Middle Lug
Fan Platform
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 11
New Platform Design (340-001-814-0)
• New platform design implemented to achieve durability goal
 More than 36,000 cycles at crack initiation
• New geometry with swaged bushings
 Middle lug bushing outer diameter increased (same pin diameter)
 Resolves also minor interferences
• New material Aluminum 7449 instead of Aluminum 7075 under evaluation
 Go-ahead in Feb 2002
• Shot-peening implemented
• Weight decreased
• Bowl seal implemented on both sides (lip seal removed)
• No need to have elastomer strip for weight balancing
Fan Platform
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Thickening
New hole for
mass and
static
balancing
optimization
Draft
removal
New
transition
radius
Constant
thickness
New
extrados
edge for
seal
Thick
bushing
New intrados edge to
prevent interference
with blade
New 340-001-814-0 Platform
Fan Platform
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New Design Schedule
• New design definition frozen
• Detailed drawings Feb 2002
• Engineering tests 2Q 2002
• Authorities submital 3Q 2002
• Authorities approval 4Q 2002
• Production introduction 1Q 2003
Fan Platform
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Field Plan
Objective : Replace all platforms by new design
Proposed Plan
• Retrofit no later than:
• Sep 30 2007 for -805/-806
• Sep 30 2008 for -809/-810
• Service Bulletin Category 2
• Recommend replacement at shop visit
• New platform production capability set up to support ~100
sets/month
Fan Platform
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Repairs
Full repair (SB 72-0271):
 Process includes: remove seals, weight, bushings and coating; resize
the bushing holes, anodize, install swaged bushings, replace seals and
balance weight
 SB72-0271 recommends swaged bushing implementation at shop visit
for engine having accumulated more than 10,000 cycles
 RD issued and available (TR 72-0038 to be ESM 72-21-20 repair 1)
– Addresses all platform damages together
– Seal bonding is a proprietary process (Le Joint Français)
– Seals can be purchased separately through CFM
– Bonding specification issued, validation through standard pull test
Fan Platform
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Repairs
Local repair - to install swaged bushings
 Repair procedure validated (Snecma No. 15-93702)
 Requires Electrolytic Anodization
– Repair sites limited due to environmental issues
 New local repair not detrimental to environment in progress
– Application of Alodine 1200, and Blindexite paste in the hole
– Wet aging tests successfully completed on coupons
– Validation expected 2nd Qtr 2002
Fan Platform

979199501

plication of Alodine 1200, and Blindexite paste in the hole – Wet aging tests successfully completed on coupons – Validation expected 2nd Qtr 2002 Fan Platform

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CFM Fan Platform