Measured Variability Of Southern Yellow Pine  Manual for LSDYNA Wood Material Model 143
PDF files can be viewed with the Acrobat® Reader®
2. USER’S MANUAL
This section is intended to be a brief user’s manual for those users who want to run the model with a cursory, rather than indepth, understanding of the underlying theory and equations. This section includes a description of the LSDYNA wood model input, a brief parameter description, and methods of fitting the parameters to data. This section concludes with a brief description of the wood model theory and an example output file.
2.1 LSDYNA INPUT
*MAT_WOOD_{OPTION}
This is material type 143. This is a transversely isotropic material and is available for solid elements in LSDYNA. The user has the option of inputting his or her own material properties (<BLANK> option) or requesting default material properties for southern yellow pine (PINE) or Douglas fir (FIR).
Options include: 

PINE 

FIR 

<BLANK> 
such that the keyword cards appear: 

*MAT_WOOD_PINE 

*MAT_WOOD_FIR 

*MAT_WOOD 
Define the following card for all options:
Card Format
Card 1 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
MID 
RO 
NPLOT 
ITERS 
IRATE 
GHARD 
IFAIL 

Type 
I 
F 
I 
I 
I 
F 
I 

Define the following cards for the PINE and FIR options:
Card 2 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
MC 
TEMP 
Q_{T} 
Q_{C} 
UNITS 
IQUAL 


Type 
F 
F 
F 
F 
I 
I 


Define the following cards for the <BLANK> option (do not define for PINE or FIR):
Card 3 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
E_{L} 
E_{T} 
G_{LT} 
G_{TR} 
n_{LT} 



Type 
F 
F 
F 
F 
F 



Card 4 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
X_{T} 
X_{C} 
Y_{T} 
Y_{C} 
S_{} 
S_{^} 


Type 
F 
F 
F 
F 
F 
F 


Card 5 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
G_{f I^} 
G_{f II } 
B 
dmax_{} 
G_{f I^} 
G_{f II^} 
D 
dmax_{^} 
Type 
F 
F 
F 
F 
F 
F 
F 
F 
Card 6 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
h_{} 
h_{C} 
n_{} 
h_{^} 
h_{C^} 
n_{^} 


Type 
F 
F 
F 
F 
F 
F 


Card 7 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
N_{} 
c_{} 
N_{^} 
c_{^} 




Type 
F 
F 
F 
F 




Define for all options:
Card 8 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
AOPT 







Type 
I 







Card 9 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
XP 
YP 
ZP 
A1 
A2 
A3 


Type 
F 
F 
F 
F 
F 
F 


Card 10 
1 
2 
3 
4 
5 
6 
7 
8 
Variable 
D1 
D2 
D3 





Type 
F 
F 
F 





Variable 
Description 
MID 
Material identification (a unique number has to be chosen)

RO 
Mass density

NPLOT 
Plotting options:
EQ. 1: Maximum of parallel and perpendicular damage (default)
EQ. 2: Perpendicular damage

ITERS 
Number of plasticity algorithm iterations (default is one iteration; values greater than 1 are not recommended)

IRATE 
Rateeffect options:
EQ. 0: Rateeffect model turned off (default)
EQ. 1: Rateeffect model turned on

GHARD 
Perfect plasticity override (values greater than or equal to zero are allowed). Positive values model latetime hardening in compression (an increase in strength with increasing strain). A zero value models perfect plasticity (no increase in strength with increasing strain). The default is zero.

IFAIL 
Erosion perpendicular to the grain:
EQ. 0: No (default)
EQ. 1: Yes (not recommended except for debugging)

Define for PINE and FIR options:
Variable 
Description 




MC 
Percent moisture content (if left blank, moisture content defaults to saturated at 30 percent)

TEMP 
Temperature in °C (if left blank, temperature defaults to room temperature at 20 °C)

Q_{T} 
Quality factor options (these quality factors reduce the clear wood tension/shear and compression strengths as a function of grade):
EQ. 0: Grades 1, 1D, 2, 2D


Predefined strengthreduction factors are:

Pine: 
Q_{T} = 0.47 in tension/shear
Q_{C} = 0.63 in compression 
Fir: 
Q_{T} = 0.40 in tension/shear
Q_{C} = 0.70 in compression 
EQ. 1:DS65 or SEL STR


Predefined strengthreduction factors are:
Q_{T} = 0.80 in tension/shear
Q_{C} = 0.93 in compression 
EQ. 2:Clear wood


Q_{T} = 1.0 in tension/shear
Q_{C} = 1.0 in compression 
GT. 0: 
Userdefined quality factor in tension (values greater than 0 and less than or equal to 1 are expected; values greater than 1 are allowed, but may not be realistic. 
Q_{C} 
Userdefined quality factor in compression (This input value is used if Q_{T} > 0. Values greater than 0 and less than or equal to 1 are expected. Values greater than 1 are allowed, but may not be realistic. If left blank when Q_{T} > 0, a default value of Q_{C} = Q_{T} is used.)

UNITS 
Unit options:
EQ. 0: gigapascals (GPa), mm, milliseconds (ms), kilograms per cubic millimeter (kg/mm^{3}), kilonewtons (kN)
EQ. 1: MPa, ms, grams per cubic millimeter (g/mm^{3}), newtons (N)
EQ. 2: MPa, mm, s, megagrams per cubic millimeter (Mg/mm^{3}), N
EQ. 3: lbf/inch^{2}, inch, s, pound second squared per inch to the fourth power (lbs^{2}/inch^{4}), pounds force (lbf)

IQUAL 
Apply quality factors perpendicular to the grain:
EQ. 0: Yes (default)
EQ. 1: No

Remarks: Material property data are for clear wood (small samples without defects such as knots), whereas real structures are composed of graded wood. Clear wood is stronger than graded wood. Quality factors (strengthreduction factors) are applied to the clear wood strengths to account for reductions in strength as a function of grade. One quality factor (Q_{T}) is applied to the tensile and shear strengths. A second quality factor (Q_{C}) is applied to the compressive strengths. As an option, predefined quality factors are provided based on correlations between LSDYNA calculations and test data for pine and fir posts impacted by bogie vehicles. By default, quality factors are applied to the parallel strengths and to the perpendicular strengths. An option is available (IQUAL) to eliminate application perpendicular to the grain.
Define for <BLANK> option only:
Variable 
Description 
E_{L} 
Parallel normal modulus

E_{T} 
Perpendicular normal modulus

G_{LT} 
Parallel shear modulus (G_{LR} = G_{LT})

G_{TR} 
Perpendicular shear modulus

n_{LT} 
Parallel major Poisson’s ratio

X_{T} 
Parallel tensile strength

X_{C} 
Parallel compressive strength

Y_{T} 
Perpendicular tensile strength

Y_{C} 
Perpendicular compressive strength

S_{} 
Parallel shear strength

S_{^} 
Perpendicular shear strength

G_{f I } 
Parallel fracture energy in tension

G_{f II } 
Parallel fracture energy in shear

B 
Parallel softening parameter

dmax_{} 
Parallel maximum damage

G_{f I ^} 
Perpendicular fracture energy in tension

G_{f II ^} 
Perpendicular fracture energy in shear

D 
Perpendicular softening parameter

dmax_{^} 
Perpendicular maximum damage

h_{} 
Parallel fluidity parameter in tension/shear

h_{c} 
Parallel fluidity parameter in compression

n_{} 
Parallel power

h_{^} 
Perpendicular fluidity parameter in tension/shear

h_{c^} 
Perpendicular fluidity parameter in compression

n_{^} 
Perpendicular power

N_{} 
Parallel hardening initiation

c_{} 
Parallel hardening rate

N_{^} 
Perpendicular hardening initiation

c_{^} 
Perpendicular hardening rate

Define for all options:
AOPT material axes option (see MAT_OPTIONTROPIC_ELASTIC for a more complete description):

EQ. 0: Locally orthotropic with material axes determined by element


EQ. 1: Locally orthotropic with material axes determined by a point in space and the global location of the element center; this is the adirection


EQ. 2: Globally orthotropic with material axes determined by vectors defined below, as with *DEFINE_COORDINATE_VECTOR

XP, YP, ZP Coordinates of point p for AOPT = 1
A1, A2, A3 Coordinates of vector a for AOPT = 2
D1, D2, D3 Components of vector d for AOPT = 2
Remarks: One common option is AOPT = 2. The user defines vectors a and d. Typically, a is the paralleltothegrain direction and d is one of the perpendiculartothegrain directions. Then, a x d = c and c x a = b, where a, b, and c are the principal material axes.
Previous  Table of Contents  Next
