Cold bending of glass: an innovative method of introducing curvature in façades

Cold bending of glass : a n i n n o v a t i v e m e t h o d o f i n t r o d u c i n g c u r v a t u r e i n f a ç a d e s

K y r i a k i C o r i n n a D a t s i o u

glass & façade technology research group

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B R E A c a d e m y – L o w c a r b o n s e s s i o n

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G l a s s i n c o n s t r u c t i o n

CampusBiotech(Genève)MurphyJahn/Mackay+Partners

Aachenairport

Moorhouse(London)Foster&Partners-Arup

61OxfordStreet(London)AHMMarchitects-Walsh

-Staticmouldbending/Sagbending

C u r v e d g l a s s – H e a t b e n d i n g m e t h o d s

-Rollerbending

Hightransportationcosts

Highenergyrequirements

Highcosts(differentmoulds)

Pooropticalquality

www.glassmachinerychina.com



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Highenergyrequirements

HightransportationcostsHighenergyandcostrequirements! ColdBentGlass

C o l d b e n t g l a s s

Advantages

ü  EnergyandcostefBicientmethod

ü  Canbeexecutedonsite

ü  Minequipmentrequirements

IACHeadquarters(NewYork)FrankGehry-DeSimone

www.archpaper.com



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ResearchfocusatUCA:

v  Stability-Opticalquality

v  Longtermstrength

Me t h o d s – S t a b i l i t y & o p t i c a l q u a l i t y



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q  Experimentalinvestigation

-Heattreated&Chemicallytoughenedglass

-Doublecurvedanticlasticshapes

-Destructivetesting

Me t h o d s – S t a b i l i t y & o p t i c a l q u a l i t y



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q  Parametricanalysis

-  boundaryconditions

-  geometricalcharacteristics

-  orientationoftheplate

-  Loadlocations

81models

-  Abaqus/CAE6.12-2

-StaticRiksanalysis

q  Numericalmodels

Ma j o r O i n d i n g s – S t a b i l i t y & o p t i c a l q u a l i t y

Localinstabilities:functionofboundaryconditions



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Coldbendingdistortion:–sinusoidaleffectalongsupporteddiagonal

Globalinstabilities:functionofplateorientation

Abruptchangeofdiagonalcurvature

Unwantedvisualdistortions→Opticalqualitydegradation→Serviceabilitylimit

User-FriendlyGuidelines

Me t h o d s - L o n g t e rm m e c h a n i c a l p e r f o rm a n c e



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q  ArtiOicialageing

Mass(1kg)

Platform

90o Tungstencarbidenib

Clampingsystem

Specimen

-  Scratching

-  Abrasion30seriesoftestsintotal

q  Evaluationmeans

-  Opticalmicroscopy -  CoaxialDoubleRigTests-  SurfaceproBilometry

Ma j o r O i n d i n g s – L o n g t e rm m e c h a n i c a l p e r f o rm a n c e



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1)  IdentiBicationofartiBicialageingparameterstoproducerealisticdamage–ImprovementofDIN52348

2)  Evaluationoflongtermstrengthofchemicallytoughenedandheattreatedglass.

q  Achievements

q  Findings

1)  Chemicallytoughenedglasshashigherabrasiveresistancecomparedtoheattreatedglass.CriticalBlawsaresigniBicantlysmaller.

2)  However,heattreatedglasshassuperiorlongtermstrengthcomparedto

chemicallytoughenedglass.

CTG HTG

C o n c l u s i o n s



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•  Coldbendingisannovelmethodofproducingcurvedglasssurfacesreducingenergyandcosts.

•  Globalandlocalinstabilitiescouldoccurduringthebendingprocessleadingtoshapechangesandopticaldistortions.

•  However, these instabilitiescanbeavoidedor theireffectcanbeminimized followingauser-friendlysetofguidelines.

•  ArtiBicial ageing of glass in a reliable/realistic manner is now possible (re-adjustment ofDIN52348).

•  Fully toughened glass exhibits a better long term performance compared to chemicallytoughenedglassandistherefore,moresuitable/safeforcoldbentapplications.

Thankyouforyour

attention

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Science

Cold bending of glass: an innovative method of introducing curvature in façades