Evaluation on the Structural Performance of

Sandwich Composite Beams for Railway Sleepers

Presenter:

Wahid FerdousPhD Candidate (Structural Engineering)

University of Southern Queensland

Toowoomba, Queensland 4350, Australia

Authors:

Wahid Ferdous, Allan Manalo and Thiru Aravinthan

2

Overview

• Introduction of the Research

• Materials and Casting Method

• Experimental Program

• Static Behaviour of Beams

• Discussion

• Application

• Conclusion

3

Introduction

• Rotting

• Splitting

• Insects attack

• Scarcity

• Corrosion

• Electrical conductivity

• Fatigue cracking

• Difficulty of packing

• Heavy weight

• High initial cost

• Low impact resistance

• Chemical attack

Timber Sleeper Steel Sleeper Concrete Sleeper

Composite Sleeper

Pro

ble

ms

Solution:

4

Types of Existing Composite Sleepers

Long Longitudinal Directional Fibres(Type 2)

Fibres in All Directions(Type 3)

Short or No Fibres (Type 1)

Materials:Recycled plastic such as plastic cups, bottles, bags etc.

Materials:Urethane resin foam is reinforced with long glass fibres

Materials:Sandwich panel, Pultruded composite etc.

Examples:TieTek, Axion EcoTrax, IntegriCo, I-Plas, Tufflex, KLP, MPW sleepers etc.

Examples:FFU synthetic sleeper

Examples:Glue laminated sleeper, Hybrid sleeper etc.

5

Performance of Composite Sleepers

Performance measurement AREMA specification

Oak Softwood Glue lam Type-1 Type-2 Type-3

Density, (kg/m3) 1096 855 960 850-1150 740 1040-2000

Modulus of elasticity, (GPa) 8.4 7.4 12.0 1.5-1.8 8.1 5.0-8.0

Modulus of rupture, (MPa) 57.9 49.3 66.9 17.2-20.6 142 70-120

Shear strength, (MPa) 5 4 4 4 10 15-20

Rail seat compression, (MPa) 4.6 3 3.9 15.2-20.6 28 40

Screw withdrawal, (kN) 22.2 13.3 n/a 31.6-35.6 65 > 60

6Typical composite sleeper concept

Mould

Sandwich

Panel

Polymer Matrix

• Excellent strength and stiffness to weight ratio• Can be engineered according to the requirements• Excellent resistance to environmental effect

Materials and casting method

• Sandwich Composite• Polymer Matrix

7

Test Properties GFRP skin Core

Long Trans

Flexure Modulus (GPa) 14.28 3.66 1.33

Strength (MPa) 317.4 135.1 14.3

Peak strain (%) 2.29 5.26 1.22

Tension Modulus (GPa) 15.38 12.63 1.03

Strength (MPa) 246.8 216.3 5.97

Peak strain (%) 1.61 2.37 0.61

Poisson’s ratio 0.25 0.13 -

Compression Modulus (GPa) 16.10 9.95 1.33

Strength (MPa) 201.8 124.2 21.3

Peak strain (%) 1.24 1.25 4.04

Poisson’s ratio - - 0.29

Shear Modulus (GPa) 2.47 2.17 0.53

Strength (MPa) 23.19 21.81 4.25

Peak strain (%) 3.08 2.38 0.81

Properties Values

Tensile strength (MPa) 14.74

Tensile strain at peak 0.042

Compressive strength (MPa) 65.46

Compressive strain at peak 0.054

Density (gm/cm3) 1.38

% Porosity 0.62

Glass transition temperature (0C) 64

Sandwich panel

Polymer matrix

8

Experimental program

1.8 mm5 mm

16.4 mm

1.8 mm

5 mm

1.8 mm

16.4 mm

1.8 mm

16.4 mm

16.4 mm

5 mm1.8 mm

5 m

m

= 80 mm

5 m

m

1.8 mm

= 90 mm

= 1

05 m

m

1.8

mm

5m

m

16.4

mm

1.8

mm

5m

m

1.8

mm

16.4

mm

1.8

mm

16.4

mm

16.4

mm

5m

m1

.8 m

m

5 mm

= 8

0 m

m

5 mm

1.8

mm

=

90 m

m

= 105 mm

Spreader beam

Load

Cell

Hydraulic

Cylinder

1400 mm

Experimental beam

Laser distance sensor

Beam

ID

Shear

span

(mm)

Width

(mm)

Depth

(mm)

Orientation

b D

F-A200 200 90 105 Flatwise

F-A400 400 90 105 Flatwise

F-A600 600 90 105 Flatwise

E-A200 200 105 90 Edgewise

E-A400 400 105 90 Edgewise

E-A600 600 105 90 Edgewise

(a) flatwise orientation (b) edgewise orientation (c) test setup (d) beam details

9

Failure behaviour of beams

F-A200 F-A400 F-A600

E-A200 E-A400 E-A600

10

0

20

40

60

80

100

0 35 70 105 140

Lo

ad

(k

N)

Displacement (mm)

Core tension

Skin compression

Skin tension

Core shear

F-A600

F-A400

F-A200

E-A200

E-A400

E-A600

static behaviour of beams

Beam

identity

Peak load Flexural

strength

Shear

strength

Elastic

modulus

(kN) (MPa) (MPa) (GPa)

F-A200 90.5 54.72 7.18 3.08

F-A400 51.0 61.68 4.05 3.01

F-A600 26.8 48.62 2.13 3.08

E-A200 75.8 53.47 6.02 2.83

E-A400 40.2 56.72 3.19 2.67

E-A600 29.2 61.80 2.32 2.87

𝑀𝑂𝑅 =𝑃

4𝐼𝑒𝑓𝑓; 𝐸𝐼 𝑒𝑓𝑓 =

3𝐿2 − 4 2

48

∆𝑃

∆𝑣𝜏 =

3𝑃

4 ;

11

discussion

0

20

40

60

80

0 200 400 600 800

Fle

xu

ral

stre

ng

th (

MP

a)

Shear span (mm)

Flatwise

Edgewise0

2

4

6

8

0 200 400 600 800

Sh

ear

stre

ng

th (

MP

a)

Shear span (mm)

Flatwise

Edgewise0

1

2

3

4

0 200 400 600 800

Ela

stic

mo

du

lus

(GP

a)

Shear span (mm)

Flatwise

Edgewise

(a) effect on flexural stress (b) effect on shear stress (c) effect on elastic modulus

12

Application – Composite Railway Sleeper

Cases Bending strength

(MPa)

Shear strength

(MPa)

Elastic modulus

(GPa)

𝑀𝑂𝑅 𝜏 𝐸𝑎𝑝𝑝

Sandwich beam 49-62 6.0-7.2 2.7-3.1

Timber sleeper 47-110 2-7 7-26

AREMA specification 13.8 6.2 1.17

• Sandwich beam can meet the strength requirements of composite railway sleeper

13

conclusion

• The orientation of the beam plays a significant role on the failure behaviour.

• The flexural stress increases and shear stress decreases with the increase of shear spans.

• The flatwise orientation provided higher effective modulus of elasticity than the edgewise

beam. However, the shear span has no effect on the elastic modulus of the beam.

• The capacity of resisting high bending and shear forces and ease of controlling the depth,

makes the edgewise orientation a preferable choice than flatwise orientation for railway

sleeper.

14

Thanks for your attention

Acknowledgement• University of Southern Queensland for financial and material supports through Australian

Postgraduate Award (APA) scholarship

• Supports from the Department of Industry Innovation, Science, Research and Tertiary Teaching

Enterprise Connect Researcher-In-Business Funded by the Australian Government.

Contact InformationWahid Ferdous

Email: Md.Ferdous@usq.edu.au