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1E5 Design of aluminium, stainless
steel and glass structures
Martina Eliášová
2
List of lessons
1) Aluminium structures2) Design of aluminium elements3) Design of aluminium connections4) Aluminium advanced design
5) Stainless steel structures6) Stainless steel material and material properties 7) Specialty in design of stainless steel structural elements8) Connection design, erection and installation of stainless
steel structures
9) Glass as a material for load bearing structures10) Design of glass structures11) Design of glass connection12) Glass facades
3
Objectives of the lecture
• Introduction to glass structures
• Historical review
• Production - glass products, edge quality
• Material and mechanical properties
• Testing of glass elements
• Toughened glass, heat-strengthened glass, chemically strengthened glass
• Laminated glass
• Aesthetic coatings
• Conclusions
Objectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
4
Introduction
• Load bearing elements from glass
• Purpose
• Architectural aspects of new structures
• Design of glass structures
Objectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
5
Historical review
• The oldest finds of glass in Egypt – 10 000 BC• Glass blower's pipe - finding around turn of the era
• Flat glass - crown process, cylindrical process• 1871 Pilkington – machine for automated production• Beginning of the 20th century: development of various drawn flat
sheet processes• Mid-20th century: Pilkington developed float glass process
Objectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
6
Chemical composition
Typical composition:• Silica SiO2 70 – 74%• Lime CaO 5 – 12%• soda Na2O 12 – 16%• other chemical elements with influence to: spectral transmittance,
thermal properties, tensile strength, fracture toughness, colour, etc.
Glass colours produced by the addition of metal oxides• green – iron or chromium oxide • red – copper oxide or gold oxide • blue – cobalt oxide
Objectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Glass is isotropic, inorganic, visco-elastic material without lattice structure, solid at room temperature, liquid above transition zone ~580°C.
7
ProductionObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Float glass process
Melting furnace
1 500°C
Raw materials
1 600°C 1 100°C
Float bath
600°C 200°C
Annealing lehr
Cutting section
Molten tinMolten glass
• silica sand, soda ash, limestone and salt cake with cullet • controlled heating permits glass to flow• flat ribbon of uniform thickness, brilliant and flat parallel
surfaces
8
ProductionObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Float glass ribbon cut to panel size
Float glass plant
9
Glass products, edge qualityObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
• flat glasst = 3, 4, 5, 6, 7, 8, 10, 12, 15, 19, 25 mm, max. size 6,0 x 3,2 m
• channel glass C, Ulength up to 6,0 m
• circular tubethickness from 0,7 to 10,0 mm, diameters d = 3 to 325 mm
• glass blockhollow - (115 x 115 x 80 mm - 300 x 300 x 95 mm)solid - (120 x 120 x 40 mm - 200 x 200 x 50 mm)
• curved glassradius R = 300 mm - ∞depend on the thickness, bends in one or two planes
10
Glass products, edge qualityObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
mitre
bevel
round
half-round
cut
45°± 2°2 mm
Edge quality
• CUT – unfinished sides of glass with sharp edges;
• ARRISED – the sharp cut edges have been broken off or bevelled with a grinding tool
• GROUND – to required dimensions, with blank spots
• FINE GROUND – edge is fully ground over its full surfaces, without blank spots
• POLISHED – the fine ground edges are finely polished
11
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
High durability
Resistance to:• water percolation
• corrosion
• salt water
• carbonated water
• strong acids
• organic solvents
• ultra-violet radiation
12
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
MPa10 - 100Tensile strength
MPaup to 1 000Compressive strength
-0,89Emissivity ε
W/(mK)1,0Thermal conductivity λ
1/K7,7 - 8,8 x 10–6Coefficient of thermal expansion αT
-0,23Poisson's ratio ν
MPa30 000Shear modulus G
MPa70 000Young's modulus of elasticity E
kg/m32500Density ρ
UnitValueGlass property
13
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
elastic range
Stress σ
ultimate strength fk
design strength fd
Stress σ Stress σ
elastic range
plastic range
elastic range
plastic range
Strain ε
ultimate strength fu
yield strength fydesign strength fd
ultimate strength fk
design strength fd
Strain εStrain ε
GLASS STEEL TIMBER
14
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Strength of glass depends on:• surface condition and edge quality• load duration• environmental condition, especially humidity• stress distribution on the surface• size of the stressed area• damage of glass surface – flaws and cracks
15
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
10-2 100 104
1s
102
1min
Load duration1h 1d 1 year
108
0,6
0,4
1,0
2,0Relative strength
0,8
Relationship between time to failure and applied stress (Sedlacek)
16
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions16,0melting snow at 2°C
70,0vacuum
27,0air with 10% relative humidity at 25°C
18,1air with 50% relative humidity at 25°C
16,0water at 25°C – recommended for design purposes
constant nenvironment
Relationship between time to failure and applied stress
ttanconsTn =σσ - stressT - duration of stressn - constant
17
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
FRACTURE MECHANICS – growth of crack (Griffith's theory)
Critical combination of stress and crack length for fast fracture is a material constant
( ) ( )cEGa =πσa - half of the crack length, E - Young's modulus of elasticityGc - toughness of the glass [kJ/m2], (critical elastic energy release rate)
• critical length of crack x critical stress• crack grows slowly when stress σ < σcr until critical length
18
Material and mechanical propertiesObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Irregularities and defects in glass• manufacturing – in material (vents, sulphate scab,
inclusions)
• mechanical processing – sawing, cutting, drilling, edge and surface grinding
• environment – cleaning (new micro cracks and scratches are generated)
• glass has ability to reverse damage in unstressed state (i.e. heal the micro cracks)
19
Testing of glass elementsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened glass
Laminated glass
Appearance, coatings
Conclusions
Four point bending tests of glassEN 1288-3 Glass in Buildings – Determination of the bending strength of glass
• length of the test specimen: L = 1 100 mm• width of the test specimen: B = 360 mm• fluent increase of the load with speed 2 MPa/s till the failure
F
Lb
Ls
specimen
loading roller
h
supportingroller
rubber
20
Testing of glass elementsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Four point bending test of glass
• Test set-up• Typical failure of float glass
21
Testing of glass elementsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Impact test - EN 12600
• impact resistance of glass – to resist dynamic human impact• 50kg pendulum, dropping height, glass breakage
22
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Strength refined glass• Treatment of glass: greater resistance to mechanical and
thermal loads
• Three different basic types with regards to the strength and fracture patterns
Annealed float glass - insufficient strength in tension
23
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Toughened glass (fully tempered glass)
Cleaning Heating > 600°C Cooling
Manufacturing steps for tempered glass
24
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
• quenching (fast cooling) with air • cooling and stiffening first on the surface, delayed cooling
and consolidation of the core → internal stress (parabolic distribution)
• surface in compression, core in tension
CompressionTension
0,2d
0,6d
0,2d
d
25
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Advantages• high value of bending strength (compressive surface
stress 90 – 150MPa + tensile strength of annealed glass 40MPa)
• compressive stress not influenced by surface defects
• withstand local temperature differences up to 150°C (float glass 40°C)
• overloading or damage – glass breaks into numerous small pieces, not dangerous
Typical fracture pattern of tempered glass: small fragments or dice
26
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Disadvantages• glass must be at least 4mm thick• thermal treatment after mechanical work - cutting, drilling • greater initial deformation – sinusoidal waves from rollers • spontaneous fracture: invisible nickel sulphide inclusions
(NiS), which expand their volume; up to 2 years after production → destructive Heat-soak test (DIN 18516):
Nickel sulphide inclusions
27
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Weakened areas of the edge stresses in comparison to the body stresses - toughened glass
Zone 1: central area Zone 2: edge
weakening-
-
+D
0,2D
0,2D
0,6D
1 ~2,1
σ1 = σ2, σ3 = 0
A B
-
+
-+
σ2 = 0
σ1 ≠ σ2, zone 2σ3 ≠ 0
~D
-
-
+
+D
0,2D
0,2D
0,6D
zone 1,σ1 = σ2
σ3 = 0
28
Toughened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Toughened glass upon loading
tension
Stress distribution in toughened glass
Bending stress
compression compressiontension
tension
compression
=+
29
Heat strengthened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened
glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Heat strengthened glass (partially tempered glass)• similar production – from same initial temperature slower
cooling• reduction of the surface pre-stress level (35 – 55 MPa)• withstand local temperature differences up to 100°C• greater initial deformation in comparison with float glass
compression tension0,2d
d 0,6d
0,2d
tension0,2d
0,2d
0,6dd
compression
internal stress: 90 – 150 MPa internal stress: 35 – 55 MPa
30
Heat strengthened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened
glass
Chemically strengthened
galss
Laminated glass
Appearance, coatings
Conclusions
Advantages• without spontaneous failures due to nickel sulphide
inclusions• fragmentation similar to annealed glass = keep glass
panes in position after cracking when they are framed or laminated
Comparison of fracture pattern:float x heat-strengthened glass
Comparison of fracture pattern:heat-strengthened x tempered glass
31
Heat strengthened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened
glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Determination of the surface stress• destructive tests: fragmentation test – BS 6206, pr EN 12150
• struck in a controlled manner
• number of glass fragments in a standard area
• surface compression can be deduced from the number of fragments (higher number of fragments = increasing surface stress in given area)
• non-destructive tests: optical instrument – differential surface refractometr
32
Heat strengthened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthened
glass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Initial deformation• float glass – less than < L/2500
• thermally strength refined glass – the shape of sinusoidal waves ~ L/300
edge diproller wave roller wave and edge dip
caused by sagging in semi-molten state
overall bow slow cooled face
fast cooled face
overall bow caused by differential cooling of the two sides of the plate
33
Chemically strengthened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
• chemical pre-stressing is realized by ionic exchange
• glass pane is immersed in a hot molten salt (hot potassium chloride bath)
• smaller sodium ions in the glass surface are exchanged for the larger potassium ions
• fracture behaviour corresponds to float glass
compression tension
Stress cross-sectional diagram of chemically strengthened glass
34
Chemically strengthened glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Advantages• without thermal deformation ⇒ suitable for very thin glass
panes
• chemically strengthened glass can be cut, edge has strength of normal glass
Disadvantages• small depth of penetration ⇒ highly susceptibility to
surface defects because strengthened zone is not very deep
35
Laminated glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
with stiff interlayer bondwith flexible interlayer bond
with no interlayer / loose
• modification of the mechanical, optical properties through the selection of the component layers, their sequence and thicknessoverhead glass, wind screens, bullet proof glass, glass beams and columns, glass in automotive industry
36
Laminated glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Laminated glass with foil
• two or more glass panes bonded by a transparent interlayer of plastic (up to 25 layers, thickness over 100 mm); float glass, tempered glass, polycarbonate, bent glass
• glass panes are washed, foils are layered and the assembly is heated (70°C) and pressed (prelamination) by roller process to squeeze out the air, in autoclave is heated to 140°C under a pressure about 0,8 MPa; largest size of pane 6,0 x 3,21m
prelamination by calender
positioning and layering autoclave
37
Laminated glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Intermediate layer:• PVB foil (poly-vinyl-butyral) – basic thickness 0,38 mm,
maximal thickness of the interlayer = 6 mm• EVA (ethylene vinyl-acetate)• PU (polyurethane)• Ionoplast → SenryGlass
• influence of temperature• influence of load duration
Enter to the autoclave
38
Laminated glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Advantages• laminated glass incorporates many thicknesses and
combination of glass types ⇒ many products with required mechanical and optical properties
• “safety glass” – after failure broken glass pieces remain bonded to the foil = residual load-bearing capacity, interlayer can prevent penetration ⇒ impact test
Disadvantages• thicker foils are used with heat treated glass to
accommodate undulations = sinusoidal waves
• offset of adjacent glass edges due to the lamination process = misalignment up to 2 mm
39
Laminated glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
ConclusionsBending stress distribution of laminated glass depending on Bending stress distribution of laminated glass depending on shear modulus G of PVB interlayershear modulus G of PVB interlayer
40
Laminated glassObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Laminated glass with resin interlayer• liquid cast resin (epoxy, acrylic, polyester) • glass panels vertically positioned with defined gap (about 1 –
2mm), edges sealed with transparent double-sided adhesive tape, resin poured between two panels
• resin curing by chemical reaction or UV light
Advantages• no additional autoclave ⇒ large panel size• better acoustic insulation, • suitable for thermally strengthened glass
Disadvantages• less residual load-bearing capacity ⇒ post-fracture integrity
41
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Glass appearanceInfluence of the surface type totransmission and reflection
• perfectly smooth surface
• textured surface
• rough surface
42
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Rough surfaces of glass• Sandblasting: abrasive is blasted under pressure onto the
glass surface ⇒ glazing surface is roughened and translucent pattern is created, reduction of the strength up to 50%
• Acid etching: liquid acid bath or acid pastes / screens, very durable patterns
sand-blasted glass surface –less optical quality
etched glass surface
43
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Texture rolled glass• patterned glass is formed by reversal of pattern on the
roller and cooled down, variety of architectural appearance
• the deeper the pattern, the greater the degree of obscuration and diffusion
ornamented glass textured rolled glass surface with wire mesh
44
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Enamelled glass• ceramic pigments or frits are rolled, poured or screen-
printed over one side of glass and are baked onto the glass during heat treatment = permanent bonded
• enamelling reduces the bending strength of tempered or heat- strengthened glass about 40%
transport roller
glasscolour coating
dosing roller pressure rollercoating trough
principle of roller-applied colour coating
45
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
laminated safety glass with coloured PVB films
laminated safety glass with printed film interlayer
laminated glass with decorative interlayer = metal sheet
solar modules integrated into the glass skin
46
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Electro-optic glasstranslucent glazing (B) unit becomes transparent (A) when an electric field is applied
1. glass2. transparent electrode layer3. polymer layer with aligned liquid crystals4. polymer layer with randomly oriented liquid crystals
A
B
1 2 3
4
47
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
hard coatings• fired into the glass surface under very high temperature
600 – 650°C, metallic oxides
• advantages: hardness ⇒ can be glazed also to exterior sides, good economics in fabrication
• disadvantages: have to be integrated into the float process ⇒not flexible, maximum number of layers = 2
Coatings techniquesimpact on transmittance, absorption, reflection – solar control glass
48
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
soft coating• chemical or physical vapour deposition, most common
technique = DC-magnetron sputtering process • up to 15 different materials = big variety of the coating
composition, typical coating material tin oxide, silver, • total coating thickness about 0,01 – 0,1μm• advantages: very precise, flexible with constant quality,
possible to reproduce the same coating with the same technical properties after many years
• disadvantages: susceptibility to aggressive air pollution and mechanical damage, necessity of the protection by protective layer, placing onto the inner side of insulating units
49
Appearance, coatingsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Fire resistant glazing• special transparent gels or intumescent (swelling)
interlayer which are transparent at room temperature, but foaming above higher temperature
• glazing might break but stay in position without falling down
• special glazing products allow fire protection up to 120 minutes
50
ConclusionsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
risin
g te
nsile
be
ndin
g st
reng
th
bette
r res
idua
l saf
ety
afte
r bre
akag
e
annealed laminated safety glass- (45 N/mm2)
heat-strengthened laminated safetyglass - (70 N/mm2)
toughened laminated safety glass- (120 N/mm2)
Summary
51
ConclusionsObjectives
Introduction
Historical review
Chemical composition
Production
Glass products, edge quality
Material and mechanical
properties
Testing of glass elements
Toughened glass
Heat-strengthenedglass
Chemically strengthened
glass
Laminated glass
Appearance, coatings
Conclusions
Tension strength of glass
45/18 = 2,51848Enamelled heat-strengthened float glass
70/29 = 2,42970Heat-strengthened float glass
45/15 = 3,0
45/22,5 = 2,0
15
22,5
45
45
overhead
vertical
Laminated glass from annealed glass
25/8 = 3,1
25/10 = 2,5
8
10
25
25
overhead
vertical
Rolled glass
45/12 = 3,8
45/18 = 2,5
12
18
45
45
overhead
vertical
Annealed glass
70/30 = 2,43070Enamelled tempered float glass
90/37 = 2,43790Tempered rolled glass120/50 = 2,450120Tempered float glass
γMfd [MPa]fk [MPa]UseGlass type
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