Revisiting the Transverse Compression Modulus

Transcription

1 Revisiting the Transverse Compression Modulus Wood CellNet Workshop in Coimbra May 8, 2014 Manuel Mikczinski

2 Agenda Single fibre compression systems Nanorobotic compression Results Compression Modulus Wild (2005) E T =? 2

3 What are we talking about? 3

4 State of the Art Mechanical properties of single fibres Axial characterisation Literature Jayne (1959) Page (1971) Kersavage (1973) Burgert (2003) Only tensile characterisation Controlling environmental conditions Humidity, temperature Measurement by load cell Kersavage (1973) Burgert (2003) 4

5 State of the Art Mechanical properties of single fibres Axial characterisation Off-axis characterisation Literature Bergander (2000) Saketi (2010, 2012) Multi-cell investigations wood fibre wall slices modelling Fibre bending two-end fixed bending Saketi (2010, 2012) Bergander (2000) 5

6 State of the Art Mechanical properties of single fibres Axial characterisation Off-axis characterisation Compression / Indentation Literature Nyrén (1971) Pawlak (2001) Wild (2005) Adusumalli (2010) Zhang (2010) Ganser (2013) Composite material / network level Wood Axial pillar compression Paper Paper thickness compression Pawlak (2001) Adusumalli (2010) 6

7 State of the Art Mechanical properties of single fibres Axial characterisation Off-axis characterisation Compression / Indentation Literature Nyrén (1971) Pawlak (2001) Wild (2005) Adusumalli (2010) Zhang (2010) Ganser (2013) Fibre level Whole fibre Large section (300 µm) AFM-Indentation only fibre wall level Nyrén (1971) Wild (2005) Ganser (2013) 7

8 Nanorobotic System Environment FEI Quanta 600 SEM Low vacuum (0.8 mbar, water atm.) Nanorobotic setup PS-AMiR Coarse (50 nm) Fine (0.2 nm) Force sensor (2 mn) Control software OFFIS Automation Framework Open Source 8

9 Nanorobotic System Environment FEI Quanta 600 SEM Low vacuum (0.8 mbar, water atm.) Nanorobotic setup PS-AMiR Coarse (50 nm) Fine (0.2 nm) Force sensor (2 mn) Control software OFFIS Automation Framework Open Source 30 mm 30 mm 9

10 Nanorobotic System Environment FEI Quanta 600 SEM Low vacuum (0.8 mbar, water atm.) Nanorobotic setup PS-AMiR Coarse (50 nm) Fine (0.2 nm) Force sensor (2 mn) Control software OFFIS Automation Framework Open Source Femtotools, CH 10

11 Measurement Process Samples so far: Delignified: bleached softwood kraft pulp Reduced lignin: unbeaten chemical pulp Wood fibre: never-dried earlywood spruce Sample preparation Separate single fibres Transfer to sample holder Cut one end (free cross-section) Measurement phases Catch the fibre Load and unload Repeat loading 11

12 Measurement Process Samples so far: Delignified: bleached softwood kraft pulp Reduced lignin: unbeaten chemical pulp Wood fibre: never-dried earlywood spruce Sample preparation Separate single fibres Transfer to sample holder Cut one end (free cross-section) Measurement phases Catch the fibre Load and unload Repeat loading Loading profile Result 12

13 SEM View BSKP, collapsed lumen Spruce, never-dried 13

14 General results Direct loading of the fibre Comp. Force [µn] Compression states (C1) No contact (C2) Fibre bending substrate (C3) Compressing the lumen (C4) Compressing the fibre wall Area: Dissipation energy 14

15 Comparison of Results (1/3) Black Spruce (from Literature) Norway Spruce One-way loading Initial load: 3 mn Long measurement length: 300 µm Multi-way un-/loading No initial compression load Defined measurement area Wild (2005) 15

16 Comparison of Results (2/3) BSKP Open lumen BSKP Collapsed lumen 6 measurement cycles Curve similar to Nyrén measurement cycles Additional curve features 16

17 Comparison of Results (3/3) BSKP with an open lumen follows this graph best. The collapse-load can be determined Other fibres? Nyrén (1971) Wild (2005) 17

18 Describing the Transverse Compression Force-distance curves Nyrén: Load level for collapse Wild: No transition area Assume a homogeneous material => Compression Modulus: EE T = dd dδ δδ L w Wild (2005) Nyrén (1971) 18

19 Nanorobotic Results Fibre wall compression: dd dδ δδ EE T = L w From stiffness to elastic modulus three regimes = three moduli? fibre bending? fibre collapse fibre wall compression F, Comp. Force [µn] Transverse compression modulus: E T = E BBBB + E CCCC + E FF CCCC δ, 19

20 Defining the new Components Bending Low stress bending along the fibre Un-twisting of the fibre Collapse Bending of the free fibre wall segments Light fibre wall compression Compression Compression of the fibre wall only Is it that simple? 20

21 Simple Compression? 21

22 Density Approach Curve for ideally no material? δ Two plates pressing against each other Step response Changes correspond to the change of material density between the plates: dd dδ ~ρ F, Comp. Force [µn] F F Distinct areas State lines? δ, 22

23 Conclusion Nanorobotic transverse compression Results defined area distinct force-distance curves two-way measurements (loading + unloading) cross-section observation Refining the description Load level Stress level based to density based? Evolutionary steps Temperature control control RH MFA measurement Different loading schemes 23

24 Conclusion Nanorobotic transverse compression Results defined area distinct force-distance curves two-way measurements (loading + unloading) cross-section observation Refining the description Load level Stress level based to density based? Evolutionary steps Temperature control control RH MFA measurement Different loading schemes 24

25 Some more pressing matters? Group Automated 25 Nanohandling

26 This work has been partially carried out within PowerBonds Coordinator: Prof. Pasi Kallio A project funded by WoodWisdom-NET I greatly acknowledge the discussions with Michaela Eder and the support with Spruce fibres. 26

27 References Adusumalli (2010) R.-B. Adusumalli, R. Raghavan, R. Ghisleni, T. Zimmermann, J. Michler. Deformation and failure mechanism of secondary cell wall in Spruce late wood. Applied Physics A, vol. 100 (2), pp , Bergander (2000) A. Bergander, L. Salmén. Variations in Transverse Fibre Wall Properties: Relations between Elastic Properties and Structure. Holzfoschung, vol. 54 (6), pp , Burgert (2003) I. Burgert, K. Frühmann, J. Keckes, P. Fratzl, S.E. Stanzl-Tschegg. Microtensile Testing of Wood Fibers Combined with Video-Extensometry for Efficient Strain Detection. Holzforschung, vol. 57 (6), pp , Ganser (2013) C. Ganser, U. Hirn, S. Rohm, R. Schennach, C. Teichert. AFM nanoindentation of pulp fibers and thin cellulose films at varying relative humidity. Holzforschung, vol. 68(1), pp , Kersavage (1973) P.C. Kersavage. Moisture Content Effect on Tensile Properties of Individual Douglas-Fir Latewood Tracheids. Wood and Fiber Science, vol. 5(2), pp , Mikczinski (2013) M. Mikczinski, H.X. Nguyen, S. Fatikow. Assessing Transverse Fibre Properties: Compression and Artificial Hornification by Periodic Compression. In S. J. I'Anson, Advances in Pulp and Paper Research (vol. 2, pp ). Bury, Lancashire, UK: The Pulp and Paper Fundamental 27 Research Society, FRC, Nyrén (1971) Nyrén, J. The Transverse Compressibility of Pulp Fibres. Pulp and Paper Magazine of Canada, 72(10), pp , Pawlak (2001) J.J. Pawlak. The local compressive properties of paper in the z-direction as related to paper friction. Dissertation at the College of Environmental Science and Forestry, State Universtiy of New York, Saketi (2010) P. Saketi, A. Treimanis, P. Fardim, P. Ronkanen, P. Kallio. Microrobotic platform for manipulation and flexibility measurement of individual paper fibers. Proc. of IEEE International Conference on Intelligent Robots and Systems, Saketi (2012) P. Saketi, M. von Essen, M. Mikczinski, S. Heinemann, S. Fatikow, P. Kallio. A flexible microrobotic platform for handling microscale specimens of fibrous materials for microscopic studies. Journal of Microscopy, vol. 248 (2), pp , Wild (2005) P.M. Wild, I. Omholt, D. Steinke, A. Schuetze. Experimental Characterization of the Behaviour of Wet Single Wood-Pulp Fibres under Transvers.e Compression. Journal of Pulp and Paper Science, 31(3), pp , 2005.