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Brabec Milch Tippner Sotner Decky Cermak SWST 2020...
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NON-LINEAR MATERIAL MODEL OF MECHANICAL BEHAVIOUR OF O AK W OOD EXPOSED TO DIFFERENT RELATIVE HUMIDITY CONDITIONS This work was supported by the Specific University Research Fund of Grant No. LDF_TP_2019015 CORRESPONDING AUTHOR 2. DETERMINATION OF MATERIAL CHARACTERISTICS ε 2 γ 23 ε 1 γ 12 γ 13 ε 3 STRAIN MEASUREMENT DIGITAL IMAGE CORRELATION (CORRELATED SOLUTION -VIC) Acquisition frequency Image resolution Resolution 4 HZ 2452×2056 PX 0.001 MM POINT WISE (1 cam → 1×2D) FULL-FIELD (2 cam → 1×3D) -1 1 0 STRESS (σ; τ), MPa STRAIN (ε; γ), %; ° LL – in longitudinal direction RR – in radial direction TT – in tangential direction I. NORMAL ELASTIC MODULI (6×E) LR – in longitudinal-radial plane LT – in longitudinal-tangential plane RT – in radial-tangential plane II. SHEAR ELASTIC MODULI (3×G) LR – in longitudinal-radial plane LT – in longitudinal-tangential plane RT – in radial-tangential plane III. POISSON'S RATIOS (3×ν) C – compression test LS – long. shear test TS – transversal shear test T – tension test LL – in longitudinal direction RR – in radial direction TT – in tangential direction I. NORMAL TANGENT MODULI (6×E) LR – in longitudinal-radial plane LT – in longitudinal-tangential plane RT – in radial-tangential plane II. SHEARTANGENT MODULI (3×G) LL – in longitudinal direction RR – in radial direction TT – in tangential direction III.YIELD POINTS (6×σ + 3×τ) C – compression test T – tension test C – compression test T – tension test LR – in longitudinal-radial plane LT – in longitudinal-tangential plane RT – in radial-tangential plane LS – longitudinal shear test TS – transversal shear test LS – longitudinal shear test TS – transversal shear test 1. STANDARDIZED MECHANICALTESTS F F F F F F F F F F F COMPRESSION (SCALE 1:1) TENSION (SCALE 1:2) SHEAR (SCALE 1:1) LONGITUDINAL DIRECTION RADIAL DIRECTION T ANGENTIAL Used standards Dimensional standard Repetitions per specimen type and condition state BS EN "2-CM" 19 CO-AUTHORS Petr ČERMÁK David DĚCKÝ Martin ŠOTNER Jan TIPPNER Jaromír MILCH σ 2 τ 23 σ 1 τ 12 τ 13 σ 3 STRESS MEASUREMENT UNIVERSAL TESTING MACHINE (ZWICK Z050/TH 3A) Load cell capacity Loading rate Resolution 50 KN QUASI-STATIC 0.1 N 3. MATERIAL MODELS COLLECTING EQUILIBRIUM MOISTURE CONTENT Mendel University in Brno Faculty of Forestry and Wood Technology Department of Wood Science and Technology Martin BRABEC [email protected] 4.VERIFICATION OF MATERIAL MODELS 0 0.5 1 1.5 2 2.5 3 3.5 0 2 4 6 8 10 12 FORCE (F), KN DEFLECTION (D), MM Experiment Numerical model PARALLEL TO GRAIN 0 5 10 15 20 25 30 0 0.2 0.4 0.6 COMPRESSION TEST (SCALE 1:2) 0 5 10 15 20 25 30 0 0.3 0.6 0.9 1.2 PERPENDICULAR TO GRAIN IN RADIAL DIRECTION 0 5 10 15 20 25 30 0 0.3 0.6 0.9 1.2 PERPENDICULAR TO GRAIN IN TANGENTIAL DIRECTION DISPLACEMENT (U), MM F F F THREE-POINT BENDING TEST (SCALE 1:4) F CALIBRATION STEPS (S) RELATIVE ERROR (RE), % 0 10 20 30 40 50 60 S1 S2 S3 S4 S5 Bending rel. error All-tests mean rel. error 5. CALIBRATION OF MATERIAL MODELS II. GOAL TO BUILD UP THE COMPLETE NON-LINEAR VERIFIED AND CALIBRATED MATERIAL MODELS AND PRESENT THEM ON INTERNATIONAL LEVEL I. MOTIVATION INCONSISTENCY CAUSED BY DIFFERENCES IN MEASUREMENT TECHNIQUES, GROWTH, AMBIENT, LOADING CONDITIONS, SPECIMENS' SIZE PUBLICATIONS WITH COMPLETE SET OF MATERIAL CHARACTERISTICS DETERMINED BY INAPPROPRIATE TECHNIQUES PUBLICATIONS WITH MATERIAL CHARACTERISTICS PUBLICATIONS WITH COLLECTED MATERIAL CHARACTERISTICS THE INCOMPLETE SETS OF MATERIAL CHARACTERISTICS FOR DIFFERENT MOISTURE AND TEMPERATURE CONDITIONS UNSUITABILITY OF USED MEASUREMENT TECHNIQUES AND CALCULATION PROCEDURES THE MISSING EXPERIMENTAL VERIFICATION AND CALIBRATION OF MATERIAL CHARACTERISTICS NATURAL VARIABILITY OF WOOD PUBLICATIONS WITH COMPLETE SET OF MATERIAL CHARACTERISTICS DETERMINED BY SOPHISTICATED TECHNIQUES PUBLICATIONS WITH COMPLETE SET OF VERIFIED AND CALIBRATED MATERIAL CHARACTERISTICS DETERMINED BY SOPHISTICATED TECHNIQUES OPTIONS FOR SOURCE DATA ISSUES NUMBER OF PUBLICATIONS 0 ∞ III. W ORK PROCEDURE C 11 S 11 C 12 S 12 C 13 S 13 0 C 22 S 22 C 23 S 23 C 33 S 33 C 44 S 44 C 55 S 55 C 66 S 66 0 0 0 0 0 0 0 0 0 0 0 NOTE: FOR 3-D SPECIAL ORTHOTROPIC BODY W OOD DISINTEGRATION W OODEN STRUCTURES STRUCTURAL ELEMENTS ALL WOODEN JOINTS [C] Compliance material matrix Stiffness material matrix [S] 0 % 6 % 12 % 18 % 24 % [C] [S] [C] [S] [C] [S] [C] [S] [C] [S]
Transcript of Brabec Milch Tippner Sotner Decky Cermak SWST 2020...
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NON-LINEAR MATERIAL MODEL OF MECHANICAL BEHAVIOUROF OAK WOOD EXPOSED TO DIFFERENT RELATIVE HUMIDITY CONDITIONS
This work was supported by the Specific University Research Fund of
Grant No. LDF_TP_2019015
CORRESPONDING AUTHOR
2. DETERMINATION OF MATERIAL CHARACTERISTICS
ε2 γ23
ε1 γ12 γ13
ε3
STRAIN MEASUREMENT DIGITAL IMAGE CORRELATION(CORRELATED SOLUTION -VIC)
Acquisition frequency
Image resolution
Resolution
4 HZ2452×2056 PX
0.001 MM
POINT WISE(1 cam → 1×2D)
FULL-FIELD(2 cam → 1×3D)
-1
10
ST
RE
SS
(σ; τ
), M
Pa
STRAIN (ε; γ), %; °
LL – in longitudinal direction
RR – in radial direction
TT – in tangential direction
I. NORMAL ELASTIC MODULI (6×E)
LR – in longitudinal-radial plane
LT – in longitudinal-tangential plane
RT – in radial-tangential plane
II. SHEAR ELASTIC MODULI (3×G)
LR – in longitudinal-radial plane
LT – in longitudinal-tangential plane
RT – in radial-tangential plane
III. POISSON'S RATIOS (3×ν)
C – compression test
LS – long. shear test
TS – transversal shear test
T – tension test
LL – in longitudinal direction
RR – in radial direction
TT – in tangential direction
I. NORMAL TANGENT MODULI (6×E)
LR – in longitudinal-radial plane
LT – in longitudinal-tangential plane
RT – in radial-tangential plane
II. SHEAR TANGENT MODULI (3×G)
LL – in longitudinal direction
RR – in radial direction
TT – in tangential direction
III. YIELD POINTS (6×σ + 3×τ)
C – compression test
T – tension test
C – compression test
T – tension test
LR – in longitudinal-radial plane
LT – in longitudinal-tangential plane
RT – in radial-tangential plane
LS – longitudinal shear test
TS – transversal shear test
LS – longitudinal shear test
TS – transversal shear test
1. STANDARDIZED MECHANICAL TESTS
F
F
F
F
F
F
F
F
F
F
F
COMPRESSION(SCALE 1:1)
TENSION(SCALE 1:2)
SHEAR(SCALE 1:1)
LO
NG
ITU
DIN
AL
DIR
EC
TIO
NR
AD
IAL
DIR
EC
TIO
NT
AN
GE
NT
IAL
Used standards
Dimensional standard
Repetitions per specimen type and condition state
BS EN"2-CM"
19
CO-AUTHORS
Petr ČERMÁK
David DĚCKÝ
Martin ŠOTNER
Jan TIPPNER
Jaromír MILCH
σ2 τ23
σ1 τ12 τ13
σ3
STRESS MEASUREMENT
UNIVERSAL TESTING MACHINE(ZWICK Z050/TH 3A)
Load cell capacity
Loading rate
Resolution
50 KNQUASI-STATIC
0.1 N
3. MATERIAL MODELSCOLLECTING
EQUILIBRIUM MOISTURE CONTENT
Mendel University in BrnoFaculty of Forestry and Wood TechnologyDepartment of Wood Science and Technology
Martin BRABEC
4. VERIFICATION OF MATERIAL MODELS
0
0.5
1
1.5
2
2.5
3
3.5
0 2 4 6 8 10 12
FO
RC
E(F
), K
N
DEFLECTION (D), MM
Experiment
Numerical model
PARALLEL TO GRAIN
0
5
10
15
20
25
30
0 0.2 0.4 0.6
CO
MP
RE
SS
ION
TE
ST
(SC
AL
E1:
2)
0
5
10
15
20
25
30
0 0.3 0.6 0.9 1.2
PERPENDICULAR TO GRAININ RADIAL DIRECTION
0
5
10
15
20
25
30
0 0.3 0.6 0.9 1.2
PERPENDICULAR TO GRAININ TANGENTIAL DIRECTION
DISPLACEMENT (U), MM
F
F F
THREE-POINT BENDING TEST(SCALE 1:4)
F
CALIBRATION STEPS (S)
RE
LA
TIV
EE
RR
OR
(RE
), %
0
10
20
30
40
50
60
S1 S2 S3 S4 S5
Bending rel. error
All-tests mean rel. error
5. CALIBRATION OFMATERIAL MODELS
II. GOAL
TO BUILD UP THE COMPLETE NON-LINEAR VERIFIED AND CALIBRATEDMATERIAL MODELS AND PRESENT THEM ON INTERNATIONAL LEVEL
I. MOTIVATION
INCONSISTENCY CAUSED BY DIFFERENCES IN MEASUREMENT TECHNIQUES, GROWTH, AMBIENT, LOADING CONDITIONS, SPECIMENS' SIZE
PUBLICATIONS WITH COMPLETE SET OF MATERIAL CHARACTERISTICSDETERMINED BY INAPPROPRIATE TECHNIQUES
PUBLICATIONS WITH MATERIAL CHARACTERISTICS
PUBLICATIONS WITH COLLECTED MATERIAL CHARACTERISTICS
THE INCOMPLETE SETS OF MATERIAL CHARACTERISTICS FOR DIFFERENTMOISTURE AND TEMPERATURE CONDITIONS
UNSUITABILITY OF USED MEASUREMENT TECHNIQUES AND CALCULATIONPROCEDURES
THE MISSING EXPERIMENTAL VERIFICATION AND CALIBRATION OF MATERIALCHARACTERISTICS
NATURAL VARIABILITY OF WOOD
PUBLICATIONS WITH COMPLETE SET OF MATERIAL CHARACTERISTICSDETERMINED BY SOPHISTICATED TECHNIQUES
PUBLICATIONS WITH COMPLETE SET OF VERIFIED AND CALIBRATED MATERIALCHARACTERISTICS DETERMINED BY SOPHISTICATED TECHNIQUES
OPTIONS FOR SOURCE DATA ISSUES
NU
MB
ER
OF
PU
BL
ICA
TIO
NS
0
∞
III. WORK PROCEDURE
C11S11
C12S12
C13S13 0
C22S22
C23S23
C33S33
C44S44
C55S55
C66S66
0 0
0 0 0
0 0 0
0 0
0
NOTE: FOR 3-D SPECIAL ORTHOTROPIC BODY
WOOD DISINTEGRATION WOODEN STRUCTURES
STRUCTURAL ELEMENTS ALL WOODEN JOINTS
[C] Compliance material matrix
Stiffness material matrix[S]
0 % 6 % 12 % 18 % 24 %
[C]
[S]
[C]
[S]
[C]
[S]
[C]
[S]
[C]
[S]
