FRANZ NIKOLAUS PÖLZL
MECHANICAL BEHAVIOR OF COLD-BENT INSULATION GLASS UNITS MASTER‘S THESIS
FRANZ NIKOLAUS PÖLZL
MECHANICAL BEHAVIOR OF COLD-BENT INSULATION GLASS UNITS MASTER‘S THESIS
CONTENTS 1
motivation and objectives
2
bending of glass
3
parameter study
4
conclusions
01
CONTENTS 1
motivation and objectives
2
bending of glass
3
parameter study
4
conclusions
01
1 MOTIVATION AND OBJECTIVES -smooth and aesthetic building skin -no standardization in structural glazing -mechanical behavior of cold-bent IGU‘s ??? -economical method at the construction site „My objective is an outcome which is able to advance the research in this promising branch of facade engineering“
02
1 MOTIVATION AND OBJECTIVES -smooth and aesthetic building skin -no standardization in structural glazing -mechanical behavior of cold-bent IGU‘s ??? -economical method at the construction site My objective is an outcome which is able to advance the research in this promising branch of facade engineering.
02
CONTENTS 1
motivation and objectives
2
bending of glass
3
parameter study
4
conclusions
03
2 BENDING OF GLASS methods -hot-bending -cold bending
04
2 BENDING OF GLASS methods -hot-bending -well-tried way of bending glass -reshape flat glass by heat -reshaping accordingly to the underlying formwork -small bending radii are possible -economical for mass production -shoddy surface parallelism
-cold bending
04
2 BENDING OF GLASS methods -hot-bending -cold bending
05
2 BENDING OF GLASS methods -hot-bending -cold bending -is done after the glass is tempered -hence, it retains it‘s mechanical properties of safety glass -smaller bending radii than hot-bent glass -good optical quality -economical for small quantities
05
2 BENDING OF GLASS insulating glass unit (IGU) 1 2 3 4 5 6
glass pane glass pane metallic spacer bar dessicant primary seal (butyl) secondary seal (silicone)
06
MODELLING OF THE IGU volume element, 2nd order
glass panes: volume element, 2nd order
07
MODELLING OF THE IGU volume element, 2nd order
glass panes: volume element, 2nd order secondary seal: volume element, 2nd order
07
MODELLING OF THE IGU shell element, 2nd order
glass panes: volume element, 2nd order secondary seal: volume element, 2nd order spacer bar: shell element, 2nd order
07
MODELLING OF THE IGU butyl (primary seal) is neglected
glass panes: volume element, 2nd order secondary seal: volume element, 2nd order spacer bar: shell element, 2nd order primary seal: is neglected
07
MODELLING OF THE IGU butyl (primary seal) is neglected
glass panes: volume element, 2nd order secondary seal: volume element, 2nd order spacer bar: shell element, 2nd order primary seal: is neglected
07
MODELLING OF THE IGU
master
slave to the glass panes master to secondary seal master/slave contact
master
/\/\/\/\/\/\/\
/\/\/\/\/\/\/\/\/\/\/\/
master/slave contact
glass panes: volume element, 2nd order secondary seal: volume element, 2nd order spacer bar: shell element, 2nd order primary seal: is neglected tied
tied
all interactions are described by static interaction properties either by master/slave interactions with hard contact or by tying the parts together
slave tied
/\/\/\/\/\/\/\
tied
08
CONTENTS 1
motivation and objectives
2
bending of glass
3
parameter study
4
conclusions
09
IGU MODELS
10
IGU MODELS
single-curved or single-bent
double-curved or double-bent
10
single-bent IGU
parameter study
doublebent IGU
case study
parameter study
reference model
thickness of the glass pane
reference model
support situation 1
thickness of the glass pane
parameter study
depth of the cavity
case study
support situation 2
aspect ratio
outcome
young‘s modulus of the secondary seal
parameter study
support situation 3
stainless steel spacer and aluminum spacer
outcome
aspect ratio
11
SINGLE-BENT IGU thickness of the glass panes
///////////
x=y=z=0 z
x
y
12
SINGLE-BENT IGU thickness of the glass panes
z
x
y
12
SINGLE-BENT IGU thickness of the glass panes
///////////
x=y=z=0 z
x
y
12
SINGLE-BENT IGU
13
single-bent IGU
parameter study
doublebent IGU
case study
parameter study
reference model
thickness of the glass pane
reference model
support situation 1
thickness of the glass pane
parameter study
depth of the cavity
case study
support situation 2
aspect ratio
outcome
young‘s modulus of the secondary seal
parameter study
support situation 3
stainless steel spacer and aluminum spacer
outcome
aspect ratio
14
single-bent IGU
parameter study
doublebent IGU
case study
parameter study
reference model
thickness of the glass pane
reference model
support situation 1
thickness of the glass pane
parameter study
depth of the cavity
case study
support situation 2
aspect ratio
outcome
young‘s modulus of the secondary seal
parameter study
support situation 3
stainless steel spacer and aluminum spacer
outcome
aspect ratio
14
SINGLE-BENT IGU thickness of the glass panes
Glass pane 2
IGU
Secondary Seal
Spacer
Glass pane 1
IGU
Glass pane 1 ///////////
x=y=z=0 /////////////////////////////
x=y=z=0
15
SINGLE-BENT IGU thickness of the glass panes
16
SINGLE-BENT IGU thickness of the glass panes 10 mm 8 mm 6 mm
16
SINGLE-BENT IGU thickness of the glass panes 10 mm 8 mm 6 mm
16
SINGLE-BENT IGU thickness of the glass panes glass pane 2, 6mm
10 mm 8 mm 6 mm
glass pane 1, 6 mm glass pane 2, 10 mm
the „other“ glass pane thickness (glass pane 2) does not have a significant influence on the stress in the considered glass pane (glass pane 1) glass pane 1, 6 mm
16
SINGLE-BENT IGU stainless steel vs. aluminum spacer bars
glass pane 2
axis 5-5 axis 6-6
axis 5-5 axis 6-6
glass pane 1
subconstruction
17
SINGLE-BENT IGU
axis 5-5 axis 6-6
stainless steel vs. aluminum spacer bars
Stainless steel
Aluminum
17
SINGLE-BENT IGU stainless steel vs. aluminum spacer bars
axis 5-5 axis 6-6
yielding of stainless steel at 230 N/mm²
Stainless steel
Aluminum
17
SINGLE-BENT IGU stainless steel vs. aluminum spacer bars
axis 5-5 axis 6-6
Aluminum spacer bar reaches ultimate strength
Stainless steel
Aluminum
17
SINGLE-BENT IGU aspect ratio / length of the IGU
18
SINGLE-BENT IGU aspect ratio / length of the IGU
18
SINGLE-BENT IGU aspect ratio / length of the IGU
18
SINGLE-BENT IGU aspect ratio / length of the IGU
18
SINGLE-BENT IGU aspect ratio / length of the IGU
5.6% 25%
18
SINGLE-BENT IGU aspect ratio / length of the IGU
5.6%
12.5% 25%
18
DOUBLE-BENT IGU
z
x y
19
DOUBLE-BENT IGU
z
x y
19
DOUBLE-BENT IGU
z
x y
19
DOUBLE-BENT IGU
20
single-bent IGU
parameter study
doublebent IGU
case study
parameter study
reference model
thickness of the glass pane
reference model
support situation 1
thickness of the glass pane
parameter study
depth of the cavity
case study
support situation 2
aspect ratio
outcome
young‘s modulus of the secondary seal
parameter study
support situation 3
stainless steel spacer and aluminum spacer
outcome
aspect ratio
21
DOUBLE-BENT IGU aspect ratio / length of the IGU
22
DOUBLE-BENT IGU aspect ratio / length of the IGU
23
DOUBLE-BENT IGU aspect ratio / length of the IGU membrane stresses
no membrane stresses
23
DOUBLE-BENT IGU aspect ratio / length of the IGU
23
DOUBLE-BENT IGU aspect ratio / length of the IGU
23
DOUBLE-BENT IGU aspect ratio / length of the IGU
deformation plateau
anticlastic shape
23
CONTENTS 1
motivation and objectives
2
bending of glass
3
parameter study
4
conclusions
24
4 CONCLUSIONS -Glass pane thickness in the thicker of both glass panes determines the maximum principal stress
25
4 CONCLUSIONS -Glass pane thickness in the thicker of both glass panes determines the maximum principal stress -Aluminum as a material for spacer bars is not suitable due to it‘s low ductility
25
4 CONCLUSIONS -Glass pane thickness in the thicker of both glass panes determines the maximum principal stress -Aluminum as a material for spacer bars is not suitable due to it‘s low ductility
-Spacer bars have to be made out of a ductile material -Stainless steel as a material for spacer bars is suitable
25
4 CONCLUSIONS -Glass pane thickness in the thicker of both glass panes determines the maximum principal stress -Aluminum as a material for spacer bars is not suitable due to it‘s low ductility
-Spacer bars have to be made out of a ductile material -Stainless steel as a material for spacer bars is suitable
-The shear deformation, hence the strain in the edge zone is high -High performance structural silicone for long-term applications
25
4 CONCLUSIONS -Glass pane thickness in the thicker of both glass panes determines the maximum principal stress -Aluminum as a material for spacer bars is not suitable due to it‘s low ductility
-Spacer bars have to be made out of a ductile material -Stainless steel as a material for spacer bars is suitable
-The shear deformation, hence the strain in the edge zone is high -High performance structural silicone for long-term applications
-Membrane stresses in the glass panes occur for small aspect ratios and thin glass pane thicknesses for the double-bent IGU → Prevent a perfectly anticlastic shape → Can be an issue regarding the optical quality 25
FRANZ NIKOLAUS PÖLZL
Thank you for your attention
SINGLE-BENT IGU depth of the cavity
SINGLE-BENT IGU young‘s modulus of the secondary seal
DOUBLE-BENT IGU thickness of the glass panes
DOUBLE-BENT CASE STUDIES support situations 1
2
3
MESH SIZE
Part Glass pane Secondary seal, circumferential Secondary seal along its height/width Spacer along its length Spacer along its height/width Subconstruction
Seeding method By size, double By size, double
Mesh size 0.01 to 0.1 m 0.005 to 0.05 m
By number, 4/3
0.005/0.003 m
By size, double By number, 4/3
0.005 to 0.05 m 0.005/0.003 m
By size, double
0.02 to 0.2 m
MODELLING OF THE IGU
04