mechanical properties of laminated glass

7/29/2019 Mechanical Properties of Laminated Glass

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Mechanical Properties ofLaminated Glass: FEM Study


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About Saflex

Saflex, a unit of Solutia Inc., is the worlds

largest manufacturer of polyvinyl butyral (PVB)interlayers for laminated glass.

For more than 80 years, Saflex has been

providing real-world solutions for every glazing

challenge collaborating with architects,

engineers and fabricators to meet the most

demanding glazing designs.


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Markets - Automotive

Saflex protective interlayers are the worldsleading brand of laminated glazing interlayersand can be found in nearly 50% of automobilesworldwide.

Saflex protective interlayers are used

commercially by vehicle manufacturers inwindshields, side windows, rear windows andpanoramic roof applications.

Benefits from automotive laminated glass madewith Saflex include: interior noise reduction,weight reduction, security, safety and enhancedcolor.


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Markets - Architectural

Recognized as the worlds leading brand of PVB

interlayers, Saflex interlayers are used incommercial and residential applications.

Saflex interlayers can resist hurricane-force

winds and wind-borne debris, plus provideadditional safety, solar, security and soundcontrol advantages.

The Vanceva color system by Saflex provideslimitless color possibilities for innovative glazingdesign.


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Saflexs speakers

Grard SavineauArchitectural Application Manager for Saflex Europe/Africa

Associated with Saflex for more than 30 years, and guestspeaker of GPD since 1995

Mr. Savineau will be presenting:

Mechanical properties of laminated glass,

FEM study

During the Glass in Architecture Use of Laminated Glass

(Monday June 18th)


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Mechanical Properties ofLaminated Glass: FEM Study

Authors:

Solutia Europe S.A./N.V.

Paper prepared by Pol dHaene

Presented by Grard Savineau


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Outline

Introduction

Rheological Model

Deformation Study

Results Conclusions


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Introduction

Predict the deformation of laminated

safety glass based on different PVBinterlayers under different loads/boundaryconditions and at different temperatures.

Solutia FEM: ABAQUS Program Experimental data generated by TNO

Comparison between the experiments(TNO) and the software simulations fromSolutia & DuPont


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Rheological Model

Establish a mathematical description for

the mechanical properties of the interlayer Dynamic rheological experiments from 0C

to 80C Definition of a mastercurve by shifting the

dynamic moduli at 20C (time-temperature

superposition principle)


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Standard Saflex PVB

Master Curve

frequency (rad/sec)

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 102 103 104 105 106

G',G''(Pa)

104

105

106

107

108

109

Storage modulus G'

Loss modulus G''

reference temperature = 20C


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Rheological Model

Transformation of the mastercurve into a

relaxation curve (Ninomiya and Ferry) Comparison of the calculated relaxation

curve with the visco-elastic model for PVBpublished by DuPont (S.J. Bennisons

model)

Solutias model slightly different from

Bennisons model.


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Relaxation Curve for

Standard Saflex PVB Interlayer

Relaxation time (s)

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

105

106

107

108

G(t)

105

106

107

108

109

experimental data

bennison model

fitted relaxation curve


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Shift Factor

Meaningfulness Express the degree of shifting required to

correlate the dynamic moduli at anytemperature to the moduli at the reference

temperature

Used to calculate the mechanical

properties of PVB at temperatures

deviating from the reference temperature


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Shift Factor of Standard PVB Interlayer

as a Function of Temperature

Temperature (C)

0 20 40 60 80 100

shiftfactor

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

10010

1

102

103

104

105

experimental data


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Deformation Study

Experimental set-up (TNO)

Solutia Model: Element type for the viscoelastic layer:

C3D8IH element Element type for the glass: C3D8I element or

a continuous shell element

Amount of elements per layer ~900

Temperature range: 5 to 40C


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Experimental Set-up

Simple 4-side support

Pressure load representing

the weight of laminate

Additional force (200 N)

applied to the surface

in middle of laminate

1.25 m

1.25 m

44.2 Configuration


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Results

Central Laminate Deflection at 5C

Time (sec)

0 1000 2000 3000

Middlepointdeformation(mm)

0.0

0.5

1.0

1.5

2.0

2.5

Solutia model - 5C

Dupont 5C

lam A 5C

lam B - 5C

lam C - 5C

construction: 3.9 mm glass/0.76 mm PVB/ 3.9 mm glassload= during 5 first seconds deformation is due to own weight

after 5 sec.: 200 N force is applied in middle of the laminate


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Results


Time (sec)

0 1000 2000 3000

Middlepointdeformation(mm)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

solutia model - temp=10C

10C Dupont model

10C lam A

10C lam B

10C lam C


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Results


Time (sec)

0 1000 2000 3000

Mid

dlepointdeforma

tion(mm)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

solutia model - 20C

dupont model 20Clam A 20C

lam B 20C

lam C 20C


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Results


Time (sec)

0 1000 2000 3000

Middlepointdeform

ation(mm)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Solutia model - 40C

Dupont 40C

lam A - 40Clam B - 40C

lam C - 40C


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5C

20C

40C

Tensile Stresses in the Central Cart of the

Laminate as a Function of Temperature

(data after 1 hour

under stress)


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Results

Mid Plane Deflection for 2-sidesSupported Laminate (temperature = 20C)

Time (sec)

0 1000 2000 3000

Middlepointdeformation

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.04.5

5.0

5.5

6.0

6.5

7.0

7.58.0

prediction based on Solutia m odel

lam A

lam B

lam C

construction: 3.9 mm glass/0.76 mm PV B/ 3.9 mm glassload= during 5 first seconds deformation is due to ow n weight

after 5 sec.: 200 N force is applied in middle of the laminatelaminate is only supported on two sides


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Results

Effect of windload duration on the panel deflection

Time (sec)

0 20 40 60


0.0

0.5

1.0

1.5

2.0

2.5

3.0

wind velocity = 120 km/h - 3 sec

120 km/h - 10 sec

120 km/h - 60 sec

deform. in case of 7.8 mm glass paneldeform. in case of a 8.56 mm glass panel

laminate=3.9 mm glass/0.76 mm PVB/3.9 mm glass


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Results

Recovery of the Laminate Deflection Over Time

Time (sec)

0 100 200 300 400 500

Middlepointdefo

rmation

0.0

0.5

1.0

1.5

2.0

2.5

3.0

120 km/h - 60 sec

Recovery


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Results

Mid point deflection at 20C

Time (sec)

0 20 40 60 80 100 120

Middlepoint

deformation

0

5

10

15

20

25

30standard PVB-20C

RM-20CDN G

VSO-2-20C

7.8 mm glass

twice 3.9 mm glass

size of laminate = 3 m x 2 m

temperature = 20C

applied pressure = 1000 Pa


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Results

Mid point deflection at 30C.

Time (sec)

0 20 40 60 80 100 120

Middlepointde

formation

0

2

4

6

8

10

12

14

16

18

20

22

24

26

standard PVB 30C

RM-30C

VSO2-30C

7.8 mm glass


temperature = 30C


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ResultsMid point deflection at 40C

Time (sec)

0 20 40 60 80 100 120

Middlepoin

tdeformation

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

standard

VSO2RM


temperature=40C


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Results

Mid point deflection at 50C

Time (sec)

0 20 40 60 80 100 120


0

2

4

68

10

12

14

16

18

20

22

24

26

28

30

32

34

standard

RM

VSO2

7.8 mm glass

twice 3.9 mm glass


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Results

Glass Strength factor

Difficult to define a single value because itdepends on The temperature

The duration of the load (short term or long term)

The viscoelastic properties of the interlayer (Tg)

The relative thickness of the interlayer

The center deformation of standard laminated

glass is larger than the deformation of amonolithic glass of the same thickness butalways smaller than the deformation of thedecoupled glass.


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Conclusions

FEM (ABAQUS) was developed by Solutia topredict the deformation of laminated glass.

Predicted values (FEM) fit with experimentaldata (TNO)

Degree of correlation depends on the

rheological model but in general a good matchwas observed

Solutias FEM allows to calculate the Glass

Strength Factor for laminated glass The bending stiffness of laminate remains higher

than the fully decoupled glass panels


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Thanks for your attentionQuestions?


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mechanical properties of laminated glass

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