Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Finite Element Modeling of the
Fastening Systems and the Concrete
Sleepers in North America
George Zhe Chen, Moochul Shin, and Professor. Bassem O. Andrawes
10th International Heavy Haul Association Conference
4-6 February 2013
New Delhi, India
Slide 2 Modeling of Concrete Crosstie and Fastening System
Outline
• Research Objective and the Role of Modeling
• State of the Art
• Component Modeling
• System Modeling
• Fastening System (2D and 3D)
• Single-Sleeper System Modeling
• Multiple-Sleeper System Modeling
• Conclusions
• Future Work
Slide 3 Modeling of Concrete Crosstie and Fastening System
Data Collection
Document Depository
Groundwork for
Mechanistic Design
International Survey Report
Validated Tie and
Fastening System Model
Load Path Map
Parametric Analysis
State of Practice Report
Data Collection
Document Depository
Groundwork for
Mechanistic Design
International Survey Report
Validated Tie and
Fastening System Model
Load Path Map
Parametric Analysis
State of Practice Report
Laboratory
Study
Modeling
Field
Study
Impro
ved R
ecom
mend
ed P
ractic
es
Comprehensive
Literature Review
Loading Regime (Input)
Study
Rail Seat Load
Calculation
Methodologies
Involvement of Industry
Experts
Modeling
FRA Tie and Fastener Project Structure
Inputs Outputs/Deliverables
Slide 4 Modeling of Concrete Crosstie and Fastening System
State of the Art
(Lundqvist and Dahlberg, 2005 - Sweden)
(Yu and Jeong, 2011)
Track System Modeling
• Simplified fastening systems
• Focused on vertical loading
• Simplified support conditions
(Tangtragulwong 2009)
Slide 5 Modeling of Concrete Crosstie and Fastening System
Concrete Sleeper and Fastening System
Rail
Concrete Sleeper
Clip Insulator
Shoulder
Pad &
Abrasion
frame
Slide 6 Modeling of Concrete Crosstie and Fastening System
Component Modeling
Rail Clip Rail Clip model
Slide 7 Modeling of Concrete Crosstie and Fastening System
Rail Shoulder Rail Shoulder model
Component Modeling
Slide 8 Modeling of Concrete Crosstie and Fastening System
Rail Insulator Rail Insulator model
Component Modeling
Slide 9 Modeling of Concrete Crosstie and Fastening System
Component Modeling: Validation
• Clip Model
Mises stress contour
( Clamping force = 11.6 kN) Clamping force-displacement curves
Stress concentration due
to support 0
5000
10000
15000
20000
25000
30000
35000
0 0.02 0.04Rail
seat
Cla
mp
ing
fo
rce (
N)
Displacement (m)
Clip Model
Manufacturer Data
Slide 10 Modeling of Concrete Crosstie and Fastening System
Component Modeling: Concrete Sleeper
and Ballast • Model Features:
– Concrete material property: damage plasticity model
– Connector element is used to simulate the bond
relationship between concrete and strand
– The effect of confining pressure on material property is
considered in ballast modeling
Static loading of the model (UIUC Model) 3-D elastic spring connection between concrete and strand
( Pozolo and Andrawes 2011)
Slide 11 Modeling of Concrete Crosstie and Fastening System
• A bonding force-slip relationship is defined in the model
Bonding force-slip Relationships
(Testing Data from the Kansas State University )
Component Modeling: Concrete Sleeper
and Ballast
0
500
1000
1500
2000
2500
3000
3500
4000
0.0000 0.0002 0.0004 0.0006 0.0008 0.0010
bo
nd
fo
rce (
N)
slip (m)
Slide 12 Modeling of Concrete Crosstie and Fastening System
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3
Str
an
d t
en
sil
e s
tres
s (
MP
a)
Position (m)
Full bondmodel
Slip bondmodel
Positions of strands
Rail seat area is
between 0.39 m to
0.67 m
Rail Seat Area
Component Modeling: Concrete Sleeper
and Ballast
Slide 13 Modeling of Concrete Crosstie and Fastening System
-6.00E-04
-5.00E-04
-4.00E-04
-3.00E-04
-2.00E-04
-1.00E-04
0.00E+00
1.00E-04
0 0.5 1 1.5
Su
rfa
ce c
om
pre
ssiv
e s
rtain
Position (m)
Rail Seat Area
Position of concrete
surface strain
lt = 0.48 m
Component Modeling: Concrete Sleeper
and Ballast
Rail seat area is
between 0.39 m to
0.67 m
Slide 14 Modeling of Concrete Crosstie and Fastening System
• Prestress and static loading (133.4 kN) is applied to the model
to look into component stress distribution and system
deflection.
Static loading of the model
Deformation contour
Component Modeling: Concrete Sleeper
and Ballast
Slide 15 Modeling of Concrete Crosstie and Fastening System
• In comparison with full bond model, relative-slip bond model can prevent
unreasonable stress concentration and provide more realistic simulation
for concrete-strand interaction
• At a wheel loading of 133.4 kN elasto-plastic model could provide
sufficiently accurate estimation for the performance of ballast, but non-
uniform material model is needed at higher loading
Lateral compressive stress contour
(full bond model & slip bond model)
Deformation contour of under the vertical loading
Component Modeling: Concrete Sleeper
and Ballast
Slide 16 Modeling of Concrete Crosstie and Fastening System
System Modeling: 2D and 3D Modeling
Pin Support
2D Modeling
Prestressed
Concrete Prestressed
Concrete
3D Modeling
Slide 17 Modeling of Concrete Crosstie and Fastening System
System Modeling: Fastening Systems
Clip
Shoulder Insulator
Friction Model between component:
Coulomb Model
τ𝑐𝑟𝑖𝑡 = 𝜇𝑃𝑛 > τ𝑒𝑞 = 𝜏12 + 𝜏2
2
No Slip
• Between the components:
• Force due to contact pressure
• Force due to friction stress
Slide 19 Modeling of Concrete Crosstie and Fastening System
-5000
0
5000
10000
15000
20000
25000
30000
35000
40000
0 0.1 0.2 0.3 0.4 0.5
Forc
e (
N)
L/V Ratio
System Modeling: Fastening Systems
Friction (F1) Insulator
Post (F2)
Lateral
Load
Friction + Insulator Post
+Shoulder to Pad
Shoulder to
Pad (F3)
Lateral Loading Path
Lateral Load
F1F3
F2
Slide 22 Modeling of Concrete Crosstie and Fastening System
Laboratory Test Validation
System Modeling: Single-Sleeper Modeling
Fixed at bottom
Symmetric
BC in the
middle
Slide 23 Modeling of Concrete Crosstie and Fastening System
• Strain gauges are attached to the rail to measure vertical web strain
• Lateral loading is applied on rail web.
4
5 6 7 8
9
10
14
15 16 17 18
19
20
Field
side
Gauge
side
System Modeling: Single-Sleeper Modeling
Slide 24 Modeling of Concrete Crosstie and Fastening System
4
5 6 7 8
9
10
14
15 16 17 18
19
20
Field
side
Gauge
side
System Modeling: Single-Sleeper Modeling
Comparisons of strains
-5.00E-05
-4.00E-05
-3.00E-05
-2.00E-05
-1.00E-05
0.00E+00
1.00E-05
2.00E-05
3.00E-05
0 10 20
Vert
ical
str
ain
Lateral Loading (kN)
7-test
8-test
9-test
10-test
7-model
8-model
9-model
10-model
Slide 25 Modeling of Concrete Crosstie and Fastening System
System Model: Multiple-Sleepers Modeling
• Track loading vehicle (TLV) applying vertical and lateral loads to the
track structure in field
• The symmetric model including 5 Sleepers
Simplified model:
Fastening system were replaced
by BCs and pressure
Detailed model with the fastening system
Slide 26 Modeling of Concrete Crosstie and Fastening System
Conclusions
• Clip model was validated with manufacturer data
• With the fastening system model, the loading path
(vertical and lateral) can be identified
• Current laboratory tests were validated, and good
agreement was observed
• Multiple-sleeper models have been developed and is
ready to validate the track system models in field
Slide 27 Modeling of Concrete Crosstie and Fastening System
Future Work
• Further comparisons: More measurements on the lab testing
set-ups will be deployed and compared with the models
• Large-scale modeling: More Models will be built to look into
the distribution of loading among multiple ties and the discrete
support condition of rail
• Realistic loading: More load types (vertical, lateral, and
longitudinal loads) and load forms (static and dynamic load) will
be applied to the track system to better simulate the actual
loading environment
• Parametric studies: Parametric studies about material
properties and geometric dimensions will be conducted using
the model
Slide 29 Modeling of Concrete Crosstie and Fastening System
Acknowledgements
• Funding for this research has been provided by the
Federal Railroad Administration (FRA)
• Industry Partnership and support has been provided by
– Union Pacific (UP) Railroad
– BNSF Railway
– National Railway Passenger Corporation (Amtrak)
– Amsted RPS / Amsted Rail, Inc.
– GIC Ingeniería y Construcción
– Hanson Professional Services, Inc.
– CXT Concrete Ties, Inc., LB Foster Company
• Professor Tutumluer for assisting with ballast modeling. (UIUC)
• Professor Peterman for strand bond-slip test data. (KSU)
• Amsted RPS (Jose Mediavilla) and CXT Concrete Tie Inc.
(Pelle Duong) for providing resources including engineering
drawings, models, and other advice.
FRA Tie and Fastener BAA
Industry Partners:
Questions?
Research Engineer, Ryan Kernes
Department of Civil and Environmental Engineering
University of Illinois, Urbana-Champaign
Email: [email protected]