Kompositverksamhet vid Uppsala Universitet Kristofer Gamstedt presenterar Avdelningen för tillämpad mekanik Ångströmslaboratoriet Where is the Ångström Laboratory? UPPSALA Ångström Laboratory Uppsala University http://www.teknik.uu/applmech 1
Uppsala University Founded 1477 Nine faculties 40000 students 2000 PhD students 5600 employees 454 M annual revenue Applied mechanics 3 years Our best asset: The human resources 2
Research profile Processing Property Microstructure Modeling Mechanisms Vision: Tailor structure and composition for optimal mechanical performance Composites, wood, paper, board, polymers, asphalt, implants Utbildning Hållfasthetslära, FEM, kontinuummekanik för civ.ing-program Byggingenjörsprogram Doktorandkurser i kompositmekanik och -material Vetenskapligt skrivande Examensarbeten civ.ing + högskoleingenjörer 3
Laboratorium Tekniker Peter Bergkvist Mechanical testing 100 kn, 50 kn, 200 N, 50 N, 20 N loadcells, opticalextensometry Instron(servohydraulic), Shimadzu, Scientific Rheometric 4
X-ray micro-computed tomography Skyscan1172, voxelresolution 1 µm 2 3DµCT image of wood fibre composite 5
3D strain fields from digital volume correlation Wood fibre mat before and after compression, maximum principal strain In collaboration with Mikael Sjödahl, Luleå University of Technology Code developed by Fredrik Forsberg and Mikael Sjödahl (LTU) Strain fields from Digital image correlation Aramis3D from GOM Pettersson, Neumeister, Gamstedt, Öberg Composite Structures 2006 6
In-situ mechanical testing in SEM Hitachi 1000 SEM + ESD + 300 N tensilestage Personer och projekt 7
Professor Per Isaksson Modelling of fracture in fibrous materials (prof Per Isaksson) 3DµCT from ESRF Grenoble. Computer modeling using novel particle methods. Dynamicfracturemechanicsin papermaking(per Isaksson) Modellingand experiments in dynamic fracture in a fibre web 8
Material degradation in corrugatedboard (Per Isaksson) Determine failures in loaded boxes to reveal deformations and full-scale nonlinear finite element modelling Professor Hans Bernhoff Avdelningen för elelktricitetslära Förnybar energi: Vertikalaxlade vindkraft Konstruktion av H-rotor av kompositmaterial Svänghjul i kolfiberkomposit 9
Doktorand Gabriella Josefsson Mekaniska egenskaper hos nanocellulosa-kompositer Teknisk fysik UU 2011 Josefsson et al., Int J Solids Struct, 51(2014), 945-953 Josefsson et al., Cellulose, 20(2013), 761-770 Mikczinski& Josefsson et al., IEEE Trans Rob Aut, 30(2014), 115-119 Trämekanik: Material, fogar, strukturer Bitr. lektor Ingela Bjurhager Tekn.dr. KTH Trämarterial Lektor Ivón Hassel PhD Kyoto univ Fogar och strukturer Post-doc Nico van Dijk PhD TU Delft Numerisk modellering 10
En förbättrad stödstruktur för Vasaskeppet Datorsimulering FEM Tryckbelastad träprov Doktorand Fengzhen Sun(CSC) Instrumented ultramicrotomy Nano/microscale fracture energy Mats Ericson & Henrik Lindberg 1997 11
Doktorand Sanjay Sisodia MS Warwick 2007, GKN, KTH Effekter av porer på utmattning av RTM-tillverkade kompositlaminat Doktorand Jinxing Huo(CSC-stipendiat) Additivt tillverkade patientspecifika käkimplantat Datortomografi CAD FEM strukturoptimering addiqv Qllverkning 12
Finite element model to ABAQUS Iso2mesh function saveabaqus Simple deformation example Fixed boundary condition Max Principal stress distribution Material property was assumed to be linear isotropic 13
Doktorand Thomas Joffre civ.ing. INP Pagora(Grenoble) Struktur-egenskaper hos träfiberkompositer 14
Extrusion (A) 1 pass (B) 2passes One extrustion: Shark-skin formation 15
Injection moulded samples Processing steps 1. Pulp fibre 2. Commingled material (30% pulp fibre / 70% PLA) 3. Extrusion 4. Extrusion + injection moulding 5. Extrusion 2 6. Extrusion 2 + injection moulding 16
Method X-ray micro computed tomography X-ray micro computed tomography Table-top XµCT 3D image Skyscan 1172 (Uppsala) Xradia microct-400 (Jyväskylä) Wood-fibre composite sample µm resolution 17
Binarization and segmentation (A) After reconstruction (B) After segmentation Pulp fibres Slender fibres >1 mm long 20 µm 1 mm 18
XµCT results What happens to the fibres during manufacturing process? Pulp fibres Fibres inside a dog bone sample Commingled PLA and pulp fibres 1 mm Cylindrical PLA fibres Pulp fibres 19
After extrusion Fibres have been significantly degraded Need to quantify the degradation 1 mm Image analysis: Fibre length distribution Miettinen, A., Luengo Hendriks, C.L., Chinga-Carrasco, G., Gamstedt, E.K., Kataja, M., Composites Science and Technology, 72 (2012), 1901-1908. 3D image Matlab Distribution function 20
Fibre length degradation Fibre length degradation Trees Pulp Commingled Extrusion Pelletizing Injection moulding 1-3 mm (Brändström 2001) 600 µm 580 µm 220 µm same 200 µm 21
Presence of fibre agglomerates Agglomerates 2 mm Do agglomerations cause the failure? CT Scan Modelling 6 mm 22
Fracture mechanics approach Stress Intensity Factor (SIF) approach Crack dimensions Crack orientation K Ic and K IIc of the matrix material KassirMK, SihGC. 1966. Three-dimensional stress distribution around an elliptical crack under arbitrary loadings. Journal of Applied Mechanics Strength correlation Size and orientation of largest defect controls strength Theoretical strength (MPa) 60 59 58 57 56 55 54 54 55 56 57 58 59 60 Experimental strength (MPa) 23
Slutord Tack Anders Sjögren & Co! Kompositaktiviteter Uppsala universitet Struktur-mekanismer-modelleringprediktering In-situ datortomografi, 3D FEM, mikrostrukturella parametrar 24