finite element modeling of the fastening systems and the ... · modeling of concrete crosstie and...

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

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


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


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)


Concrete Sleeper and Fastening System

Rail

Concrete Sleeper

Clip Insulator

Shoulder

Pad &

Abrasion

frame


Component Modeling

Rail Clip Rail Clip model


Rail Shoulder Rail Shoulder model

Component Modeling


Rail Insulator Rail Insulator model

Component Modeling


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


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)


• A bonding force-slip relationship is defined in the model

Bonding force-slip Relationships

(Testing Data from the Kansas State University )


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)


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


and Ballast


-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


and Ballast

Rail seat area is

between 0.39 m to

0.67 m


• 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


and Ballast


• 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


and Ballast


System Modeling: 2D and 3D Modeling

Pin Support

2D Modeling

Prestressed

Concrete Prestressed

Concrete

3D Modeling


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


-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


Laboratory Test Validation

System Modeling: Single-Sleeper Modeling

Fixed at bottom

Symmetric

BC in the

middle


• 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



4

5 6 7 8

9

10

14

15 16 17 18

19

20

Field

side

Gauge

side


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


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


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


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


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]

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