update on uiuc crosstie and fastening system finite...
TRANSCRIPT
Update on UIUC Crosstie and Fastening
System Finite Element Modeling
George Zhe Chen, Moochul Shin, and Professor Bassem O. Andrawes
AREMA Committee 30 Fall 2012 Meeting
Tampa, FL
24-26 October 2012
Slide 2 Modeling of Concrete Crosstie and Fastening System
Outline
• Role of Modeling in UIUC FRA BAA Concrete
Tie and Fastening System
• 2D Tie And Fastening System Modeling
• 3D Tie And Fastening 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
Load Path Map
Parametric Analysis
State of Practice Report
Validated Tie and
Fastening System Model
Data Collection
Document Depository
Groundwork for
Mechanistic Design
International Survey Report
Load Path Map
Parametric Analysis
State of Practice Report
Validated Tie and
Fastening System Model
Laboratory
Study
Modeling
Field
Study
Impro
ved R
ecom
mend
ed P
ractic
es
Comprehensive
Literature Review
International Tie and
Fastening System Survey
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
Flexural Strength of Prestressed Ties AREMA Chapter 30 Section 4.4.1
• Existing Content:
– Charts of unfactored bending moment values and relevant factors
– Recommendations for specific tie designs e.g. tie pad & changing width of tie
• Proposed Improvements:
– Update design methodology to include other critical parameters
(e.g. tie geometry)
– Determine updated equation about flexural performance requirement
• Methodology:
– Validation of models based on lab and field experimental data
– Parametric study based on validated model
• Timeline:
– Present model updates to Subcommittee 4 (C-30 Spring 2013)
– Submit ballot proposal to Subcommittee 4 (C-30 Fall 2013)
Slide 5 Modeling of Concrete Crosstie and Fastening System
4.4.1.2 Factored Design Flexural Values
a. In consideration of the influence of speed and
annual tonnage on tie design, the factored
capacity may be determined from:
M = B.V.T.
Where:
M = the factored design positive bending
moment at the center of the rail seat
B = the bending moment in inch-kips
taken from Figure 30-4-3. For a particular
tie length and spacing
V = is the speed factor from Figure 30-4-4
T = the tonnage factor obtained from
Figure 30-4-4
Flexural Strength of Prestressed Ties AREMA Chapter 30 Section 4.4.1
Figure 30-4-4. Tonnage and Speed factors
Slide 6 Modeling of Concrete Crosstie and Fastening System
Modeling Group Objective
• 2D Modeling
– Verify modeling techniques
– Assist instrumentation team by
recommending measurement
placement and estimating
deflection mode
– Serve preliminary test validation
• 3D Modeling
– Implement verified techniques
– Validation of component
model and system model
performance
– Conduct parametric study
based on validated model
Slide 7 Modeling of Concrete Crosstie and Fastening System
2D Modeling: Concrete Crosstie and
Fastening System
0500
1000150020002500300035004000
0 0.5 1 1.5
Fo
rce
(lb
)
Displacement (in)
Manufacturer Data Modeling
Slide 8 Modeling of Concrete Crosstie and Fastening System
2D Modeling: Stress Distribution
-18,000
-16,000
-14,000
-12,000
-10,000
-8,000
-6,000
-4,000
-2,000
0
0 1 2 3 4 5 6
Co
mp
ressiv
e S
tress (
psi)
(N
eg
ati
ve
fo
r c
om
pre
ss
ion
)
Rail Seat Width (in) Gage Side Field Side
Slide 9 Modeling of Concrete Crosstie and Fastening System
• Clip performance in the component
model is compared with clip
performance in the assembly model
• A coefficient of friction of 0.5 is assumed
for clip-insulator interaction
3D Modeling: Comparison Between
Component And Assembly Model
Slide 10 Modeling of Concrete Crosstie and Fastening System
• Based on the displacement trace of clip toe, the loading conditions
in the models are quite different
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
0.0 0.5 1.0 1.5 2.0
Rail
seat
Cla
mp
ing
Fo
rce (
lb)
Displacement (in)
Manufacturer data
Clip in componentmodelClip in assemblymodel
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0.0 0.5 1.0
Y D
isp
lacem
men
t (i
n)
X Displacement (in)
Clip in assemblymodel
Clip in componentmodel
3D Modeling: Comparison Between
Component And Assembly Model
Slide 11 Modeling of Concrete Crosstie and Fastening System
3D Modeling: Concrete And Fastening
System Model
Concrete And Fastening System Model
(UIUC Model)
Vertical Loading
Lateral
Loading
Concrete
Prestress
Clamping
Force
PLTM Test Setup
(Pulsating Load Testing Machine)
Slide 12 Modeling of Concrete Crosstie and Fastening System
• Position of strain gauges on the rail is as shown
Strain
Gauges
V1
V2
V3 Gauge
Side Field
Side
3D Modeling: Concrete And Fastening
System Model
Slide 13 Modeling of Concrete Crosstie and Fastening System
• Eccentricity of vertical loading result in local bending of the rail head
• Difference comes from both gauge position and strain direction
-0.0030
-0.0025
-0.0020
-0.0015
-0.0010
-0.0005
0.0000
0.0005
0 20000 40000
Ori
gin
al V
ert
ical
Str
ain
(in
/in
)
Lateral Loading (Lb)
-0.0006
-0.0005
-0.0004
-0.0003
-0.0002
-0.0001
0.0000
0.0001
0.0002
0.0003
0.0004
0 20000 40000
Init
ialized
Vert
ical
Str
ain
(in
/in
)
Lateral Loading (Lb)
V2-Model
V2-Test
V3-Test
V3-Model
V1-Test V1-Model
V1-Test
V1-Model
V2-Model
V2-Test
V3-Model
V3-Test
3D Modeling: Concrete And Fastening
System Model
Slide 14 Modeling of Concrete Crosstie and Fastening System
3D Modeling: Simplified Modeling Static Load Testing Machine (SLTM)
Slide 15 Modeling of Concrete Crosstie and Fastening System
3D Modeling: Simplified Modeling Strain Gauges On The Web Of The Rail
Slide 16 Modeling of Concrete Crosstie and Fastening System
3D Modeling: Simplified Modeling SLTM Model
Lateral Load
Clamping Force
Slide 17 Modeling of Concrete Crosstie and Fastening System
0.00000
0.00001
0.00002
0.00003
0.00004
0.00005
0.00006
0.00007
0.00008
0.00009
0.00010
0 1,000 2,000 3,000 4,000 5,000 6,000
Stra
in (
in/i
n)
Lateral Force (lb)
3D Modeling: Simplified Modeling Comparisons Of Strains On The Web (Gage Side)
G8-Model
G8-Test
G4-Model
G4-Test
G5-Model
G5-Test
G6-Model G6-Test
G7-Test
G7-Model
G4G5G6G7G8
Slide 18 Modeling of Concrete Crosstie and Fastening System
-0.00012
-0.00010
-0.00008
-0.00006
-0.00004
-0.00002
0.00000
0 1,000 2,000 3,000 4,000 5,000 6,000
Stra
in (
in/i
n)
Lateral Force (lb)
3D Modeling: Simplified Modeling Comparisons Of Strains On The Web (Field Side)
F6-Model
F5-Model
F4-Model
F5-Test
F8-Test
F7-Model
F7-Test
F8-Model
F6-Test F4-Test
F5F6F7F8
F4
Slide 19 Modeling of Concrete Crosstie and Fastening System
Preliminary Conclusions
• Clip component model was validated with
manufacturer data
• Clip performance in the component model is
considerably different from clip performance in the
assembly model
• Current laboratory tests (PLTM and SLTM) are
validated, and good agreement is observed
• Concrete crosstie and fastening system has been
modeled and been a good tool to estimate the rail
seat pressure
Slide 20 Modeling of Concrete Crosstie and Fastening System
Future Work
• Further laboratory comparisons: Conduct additional
experimentation in the lab to compare results with the models
• Large-scale modeling: finalize model that include multiple ties
and simplified fastening system to consider the distribution of
loading among multiple ties and the discrete support condition
of rail
• Realistic loading: Introduce additional 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: Conduct parametric studies related
material properties and geometric dimensions will be conducted
using the model
Slide 21 Modeling of Concrete Crosstie and Fastening System
Future Work: Possible Challenges
• Possible challenges:
– Moving loads along the rail
– Change from static analysis to dynamic analysis
– Distribution of crosstie lateral resistance (bottom friction &
lateral support)
– Modeling of non-uniform support condition
Slide 22 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 Erol Tutumluer for assisting with ballast
modeling (UIUC)
• 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:
Slide 23 Modeling of Concrete Crosstie and Fastening System
Questions?
George Zhe Chen and Moochul Shin
Department of Civil and Environmental Engineering
University of Illinois, Urbana-Champaign
Email: [email protected], [email protected]