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MSC Software Confidential MSC Software Confidential
Multibody dynamics simulation of an integrated
landing gear system using MSC.ADAMS
Presented By: Joey Jin
May 10, 2013
MSC Software Confidential
• MAG is the landing gear supplier to several major fixed and
rotary wing OEMs, including Bell Helicopter Textron, Eurocopter,
Agusta-Westland, Diamond Aircraft, Eclipse Aerospace, Piper
Aircraft, Turkish Aerospace Industries and the Korean Aerospace
Industry.
• Engineering capabilities include design, performance, stress and
fatigue life assessments as well as reliability analyses.
Mecaer Aviation Group (MAG)
2
MSC Software Confidential
Requirement of Redesign Nose
Landing Gear
3
MSC Software Confidential
Nose Landing Gear
4
This NLG is a semi-levered
suspension type shock strut
incorporating a single wheel/tire
installed on a wheel axle between
the two arms of a double-sided
wheel fork. This gear is a semi-
levered suspension type with the
wheel trailed backwards and free
to swivel over 360o. The shock
absorber is an oleo-pneumatic
type, with a separator piston
between oil and nitrogen chamber.
Upper Drag Brace
Lower Drag Brace
Over-center Spring
Cartridge
Turning Support
Piston
Main Fitting
Toque Link
Trailing Arm
NLG Component
Bell Crank
MSC Software Confidential
Bell Crank and Actuator
5
Actuator An electrically actuator
is equipped to perform
retraction/extension of landing
gear
Bell Crank The interface load on
the Bell Crank during the
retraction/extension cycles
needs to be monitored for
fatigue analysis
Bell Crank and Actuator
Bell
Crank
Actuator
Piston
0
2
4
6
8
0 5 10
Str
oke (
inc
h)
Time (s)
Actuator Stroke vs. Time
MSC Software Confidential
Retraction/Extension in ADAMS
6
MSC Software Confidential
Nose Landing Gear
7
A Rigid Body Model was built in
MSC.ADAMS to simulate the
Retraction/Extension of NLG.
The geometry was directly
imported from CAD software.
NLG ADAMS Model (Rigid)
MSC Software Confidential
Nose Landing Gear
8
1st Scenario:
NLG ADAMS Model (Rigid)
Upper Stopper stops the NLG at fully
retraction position, modelled by
contact between Upper Stopper and
Upper Drag Brace
Stopper acts between the Upper Drag
Brace and Lower Drag Brace. Action
at the fully extension position. It is
modelled by the contact.
Upper
Stopper
Stopper
MSC Software Confidential
Nose Landing Gear
9
NLG ADAMS Model (Rigid)
Over Centre Spring
Friction Consider
Contact
MSC Software Confidential
Nose Landing Gear
10
A Flex Body Model was built in
MSC.ADAMS to simulate the
Retraction/Extension of NLG.
Main Fitting, Upper Drag Brace
and Lower Drag Brace are
switched to flexible bodies.
2nd Scenario:
NLG ADAMS Model (Flex Body)
Flexible
MSC Software Confidential
Nose Landing Gear
11
Main Fitting, Upper Drag Brace
and Lower Drag Brace are
switched to flexible bodies.
Stiffness Matrices for the NLG at
the Fuselage/Main Fitting
attachments and Actuator
attachment are introduced into
ADAMS simulation.
3rd Scenario:
NLG ADAMS Model (Flex Body
and Flex Attachments)
Flexible
Attachment
MSC Software Confidential
Retraction/Extension Animation
12
MSC Software Confidential
Baseline: Simulation vs. Test (Rigid Bodies)
13
-1000.000
-800.000
-600.000
-400.000
-200.000
0.000
200.000
400.000
600.000
800.000
0.000 2.000 4.000 6.000 8.000 10.000 12.000
Lo
ad
(lb
f)
Time (s)
Actuator Load Spring: Stiffness=19 lbf/inch, Preload=44 lbf
Test Data
Simulation Data2e
3e
4e
5e
6e 6r
5r
4r
3r
2r
1r
1e
MSC Software Confidential
Redesign: Simulation vs. Test (Rigid Bodies)
14
-600
-500
-400
-300
-200
-100
0
100
200
300
400
500
0 1 2 3 4 5 6 7 8 9 10 11 12
Actu
ato
r F
orc
e (
lbf)
Time (s)
Stiffness=23 lbf/inch, Preload=27 lbf
Test
Rigid
MSC Software Confidential
Baseline Model (All Scenarios)
15
MSC Software Confidential
Redesign Model (All Scenarios)
16
MSC Software Confidential
Bellcrank FEA Results FEM Based Fatigue Life Assessments
17
MSC Software Confidential
Bellcrank Finite Element Model
18
Bellcrank: 10-node tetrahedral
elements with aluminium
properties
Pin: 8-node hexahedral
elements with steel properties
Bushing: neglected and glued
contact used between the
interface pin & bellcrank
Link & Actuator: interface loads
are applied to FEM through
RBE2 MPCs (baseline model)
Characteristics
MSC Software Confidential
FEM Results
19
Max. Tension & Max. Compression
Actuator Loads are taken from
Extension & Retraction curves
obtained by MSC.ADAMS
simulations.
von Mises Stress Max. Tension
Max. Compression
MSC Software Confidential
FEM Results (Displacement Distribution)
20
Point 1r Point 2r Point 3r Point 4r Point 5r Point 6r
Point 1e Point 2e Point 3e Point 4e Point 5e Point 6e
MSC Software Confidential
von Mises Stress Distribution
21
MSC Software Confidential
Max. Principal Stress Distribution
22
MSC Software Confidential
• With MSC.ADAMS, virtual prototypes of a complete landing gear
system can be built efficiently (reducing engineering time, cost
and risk);
• MSC.ADAMS models for retraction and extension cycles can be
used to improve design and to investigate quickly new ideas with
ease;
• Simulation results demonstrated good agreements with the test
data for both scenarios (baseline & redesign);
• In general, both (rigid & flex) simulations predict conservative
loads for extension and retraction cycles.
Conclusion
23
MSC Software Confidential 24