Session 29 ic2011 muszynski
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Transcript of Session 29 ic2011 muszynski
6/24/2011
1
Torsional stiffness of small‐ and medium‐size samples of cross laminated timber (CLT) panels:laminated timber (CLT) panels:optical measurements and FEM
simulations
Lech Muszyński1
Mélanie Noyel2Mélanie Noyel2
Thomas Pisaneschi2
Václav Sebera3
Benjamin Sundberg1
Rakesh Gupta1
Université H. Poincaré(University of Nancy)
Cross laminated timber (CLT or Xlam)Kreuzlagenholz (KLH)
http://www.storaenso.com/d/
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Cross laminated timber (CLT, KLH or Xlam)
CLT is manufactured in 3, 5, 7 and multilayer h d ff l b h k
v=pI3tMQ20
mzs&NR=
1
composites with different lumber thicknesses.
Maximum overall thickness: 40 cm.
Surface can be finished with wood‐based panels (e.g. sheetrock or plywood) by adhesive bonding
http://w
ww.you
tube
.com
/watch?v
Width: up to 2,95 mLength: up to 16 mThickness: up to 40 cmPre‐cutting: cuts for windows, doors, and so onWood species: Spruce , Pine or Larch (in EU)Adhesives: MUF, PRF, PUR
http://www.storaenso.com/
http://www.clt.info/
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Cross laminated timber (CLT, KLH or Xlam)
• Certified structural product in:pEU
– Germany
– France
– Spain
i– Austria
Russia
• Fire Code Approval in Canada http://www.binderholz‐bausysteme.com
Recently in NA…
http://www.fpinnovations.ca/pdfs/CLT.pdf
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CLT Movies!http://w
ww.clt.info/
Fast movie
Objectives
To investigate the viability of Oregon Hybrid Poplar for Cross laminated timber:Poplar for Cross laminated timber:
– Investigate optimal bonding conditions
– Master manufacturing small and medium scale CLT samples
Determine benchmark mechanical characteristics of– Determine benchmark mechanical characteristics of the samples
– Develop procedures for scaling up results from small‐scale samples to full‐scale elements
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Materials• Wood :Hybrid poplar, Greenwood Tree Farm
Nominal section = 6 x 1 ½ in, 8 ft long
Measured mean characteristics Moisture content = below 6%Measured thickness = 34.8 ± 1.4 mmDensity = 295 kg/m‐3 (19.4 cpf)Elastic modulus = 7.58 GPa (1 1*106 psi)Elastic modulus 7.58 GPa (1.1 10 psi)
• Adhesive :PRF resin, Hexion Specialty Chemicals, Springfield, ORResin : Cascophen LT‐5210JHardener : Cascoset FM‐6210
not exactly a structural‐grade timber
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Test proceduresBlock shear tests
Methods:
Shear‐bending test based on ASTM 3044
modified ASTM D143 (14)
modified ASTM D1037 (81‐86 & 87‐90)
P (dead weight)Δctr
Δsup
Sample E Sample L
Sample A Sample B
Shear block testsVariables
2 adhesive spread rates
Specimen geometry
2 adhesive spread rates
0.25 kg/m2 (55 lb/1000 ft2)
0.45 kg/m2 (100 lb/1000 ft2)
3 clamping pressures (12 hours)
0.34 MPa (50 psi)
Sample A Sample B
0.69 MPa (100 psi)
1.03 MPa (150 psi)
3‐8 specimens per condition, all specimens bonded at MC ~12 %
Sample E Sample L
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Shear block tests
Specimens:Shear blocks cut from small 3‐layer CLT billets bonded w/o surface prep
Shear block test results
Shear along the grains:
5 63 MP ± 1 28 MP5.63 MPa ± 1.28 MPa
(817 psi ± 186 psi)Sample A
“Rolling shear”:
2.80 MPa ± 0.45 MPa
(406 i ± 65 i)Sample B
(406 psi ± 65 psi)
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Shear block test results
Rolling shear in clear wood samples 2.80 MPa ±0.45 MPa Rolling shear in clear wood samples 2.80 MPa ±0.45 MPa
1.5
2.0
2.5
3.0
3.5
ear stress, M
Pa
Type L avg Spread rate 0.25 kg/m2Spread rate 0.45 kg/m2
1.5
2.0
2.5
3.0
3.5
ear stress, M
Pa
Type E avg Spread rate 0.25 kg/m2Spread rate 0.45 kg/m2
Sample L Sample E Sample B
0.0
0.5
1.0
0.34 MPa (50 psi) 0.69 MPa (100 psi) 1.03 MPa (150 psi)
Max sh
e
clamping pressure
0.0
0.5
1.0
0.34 MPa (50 psi) 0.69 MPa (100 psi) 1.03 MPa (150 psi)Max sh
e
clamping pressure
No substantial effect of adhesive spread rates (between 0.25 and 0.45 kg/m2)
Rolling shear in clear wood samples 2.80 MPa ±0.45 MPa
Shear block test results
3.0
3.5
Pa
Type L avg Type E avg
0.5
1.0
1.5
2.0
2.5
Max sh
ear stress, MP
Sample L
S l E0.0
0.34 MPa (50 psi) 0.69 MPa (100 psi) 1.03 MPa (150 psi)
clamping pressure
Sample E
Sample B
Weak effect of billet bonding pressure in specimens Type LSpecimen Type L reveals the weakest aspect of the bond(should be preferred in testing)
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Shear block test results
120%
140%
ailure
Spread rate 0.45 kg/m2 Type L Type E
0%
20%
40%
60%
80%
100%
Percen
t of rollin
g shear fa
0.34 MPa (a psi) 0.69 MPa (50 psi) 1.03 MPa (100 psi)
clamping pressure
In most cases failure is governed by rolling shear (regardless of the specimen type)
Test panels manufactured at
3‐layer, 1.22 m x 1.22 m (4 ft x 8 ft*)(4 ft x 8 ft*) *later divided into two 4 ft x 4 ftClamping pressure: not measuredPRF Spread rate: 0.45 kg/m2
3‐layer, 0.61 m x 0.61 m3 layer, 0.61 m x 0.61 m(2 ft x 2 ft)
Clamping pressure: 0.83 MPaPRF Spread rate: 0.45 kg/m2
glue line ‐
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Tests on 4 ft x 4 ft samples
Panel twisting test b d ASTM 3044
Deflection measured w/ dial gages
P = 2.8482ΔR² = 0.9984
2
4
6
8
10
12
Load, kN
Load‐Deflection
Repeatibility test
Series w/ DIC
Linear (Repeatibility test)
based on ASTM 3044
0
2
0.0 1.0 2.0 3.0 4.0
Δctr, mm
Tests on 4 ft x 4 ft samples
Panel twisting test b d ASTM 3044based on ASTM 3044
deflection measured optically
(DIC)
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Surface topography
Surface topography under load
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Deflection
Deflection paths to be analyzed
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‐6
‐4
‐2
0
2
Deflection, m
m
Deflections along ctr vertical
0.00
2.00
Deflections along the diagonal
0
2
Deflections along ctr horizontal
‐10
‐8
0 200 400 600 800 1000 1200Distance along vertical: Y, mm
Vertical in Image #20 (P=6 kN)
Vertical in Image #27 (P=0 kN)
‐10.00
‐8.00
‐6.00
‐4.00
‐2.00
0 200 400 600 800 1000 1200
Deflection, m
m
Distance along diagonal: L, mm
Diagonal in Image #20 (P=6 kN)
Diagonal in Image #27 (P=0 kN)
‐10
‐8
‐6
‐4
‐2
0 200 400 600 800 1000 1200
Deflection, m
m
Distance along horizontal: X, mm
Horizontal in Image #20 (P=6 kN)
Horizontal in Image #27 (P=0 kN)
Measurements & Simulations
P = 2.8482ΔR² = 0.9984
4
6
8
10
12
Load, kN
Load‐Deflection
Repeatibility test
Series w/ DIC
Linear (Repeatibility test)
0
2
0.0 1.0 2.0 3.0 4.0
Δctr, mm
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Simulation:4 ft x 4 ft panelSimulations based on measured longitudinal modulus of the hybrid poplar boards:
7.58 GPa (1.1*106 psi) Other elastic properties derived from relations published in 2010 FPL Wood Handbook for eastern cottonwood and yellow poplar.
27/28
‐6
‐4
‐2
0
2
Deflection, m
m
Deflections along ctr horizontal
DIC (P=6 kN, hybrid poplar)
‐10
‐8
0 200 400 600 800 1000 1200Distance along horizontal: X, mm
( y p p )
FEM (P=6 kN, cottonwood)
FEM (P=6 kN, yellow poplar)
0
2
Deflections along the diagonal
‐2
‐1
0
Deflections along ctr vertical
‐10
‐8
‐6
‐4
‐2
0 200 400 600 800 1000 1200
Deflection, m
m
Distance along diagonal: L, mm
DIC (P=6 kN, hybrid poplar)
FEM (P=6 kN, cottonwood)
FEM (P=6 kN, yellow poplar)
‐10
‐9
‐8
‐7
‐6
‐5
‐4
‐3
0 200 400 600 800 1000 1200
Deflection, m
m
Distance along vertical: Y, mm
DIC (P=6 kN, hybrid poplar)
FEM (P=6 kN, cottonwood)
FEM (P=6 kN, yellow poplar)
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Summary• Bond performance:
– No substantial effect of adhesive spread rates (between 0 25 d 0 45 k / 2)0.25 and 0.45 kg/m2)
– Weak effect of billet bonding pressure in specimens Type L– Specimen Type L reveals the weakest aspect of the bond (should be preferred in testing)
– In most cases failure is governed by rolling shear (regardless of the specimen type)
G d t b t FEM i l ti d f ll• Good agreement between FEM simulation and full field deflection measurements on loaded panels
• Data analysis is pending
Acknowledgements
Mélanie Noyel & Thomas Pisaneschi graduate interns from ENSTIB (School of Wood Science and Timber Engineering)graduate interns from ENSTIB (School of Wood Science and Timber Engineering)division of the Université Henri Poincaré (University of Nancy) in Epinal, France
Milo Clauson, OSULee Jimerson, Collins/GreenWood
Todd Miller, Hexion Specialty Chemicals
6/24/2011
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Questions?
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