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Multiple material sections may be defined with an input file. Each material section is identified by its own name. A particular name must not be referenced by a *solid/*beam/*shell section (10.5, 10.6, 10.7). In that case the respective material will be ignored. This is for an easy switching between different materials within an input data set.
The section keyword *MATERIAL must have an option
NAME=<name> 
specifies a unique name 
*MATERIAL has own subkeywords. A first subkeyword *DENSITY indicates the specific mass of the respective material. It has one data line specifying the value. Specific mass should not be confused with the specific weight, both differ by earth acceleration. The chosen mass unit has to be consistent with the units for length, force and time. If the keyword *DENSITY is not given a zero mass is assumed and dynamic calculations, if activated, are performed as quasistatic.
Each section keyword *MATERIAL must have exactly one material type keyword which has to be placed after the *DENSITY keyword, if there is one specified. The following material types are currently available:
material type 
material 
sym. tang. 
Book ( https:://www.concretefem.com) 

keyword 
dimensions 
stiffness 
Sections 

*ELASTIC 
linear elasticity 
1D, 2D, 3D 
+ 
2.4, 6.3.1 
+ phase field approach with option PHASE_FIELD 
1D 
na 
7.5.2 

+ viscoelasticity with option VISCO 
1D 
na 
3.2 

*ELASTICLT 
linear elasticity with limited tensile strength 
1D, 2D 
 
8.2 
and smeared crack 

+ strong discontinuity approach with option SDA 
2D (,3D) 
 
7.7 

replacing smeared crack 

*MISES 
Mises elastoplasticity 
1D, 2D, 3D 
 
2.4, 6.5.1 
*ISODAMAGE 
isotropic damage 
1D, 2D, 3D 
 
6.6 
*MICRODAMAGE 
microplane damage 
1D, 2D, 3D 
 
6.8 
*RCBEAM 
plane reinforced concrete cross section 

+ 
4.1.3 
*RESHEET 
plate with reinforcement sheet 
1D 
+ 
8.3 
*NLSLAB 
nonlinear model for Kirchhoff slabs 

na 
9.8 
*RCSHELL 
continuum based shell with reinforcement sheets 
3D / 1D 
 
10.7.1 
*SPRING 
nonlinear spring 

na 
3.6 
*BOND 
nonlinear bond 

+ 
8.5 
The following combinations between element types and material types are currently implemented (* is wild card):
B21* 
B23* 
T* 
S1D2 
CP* 
SB3 
SH* 
C3D* 

*ELASTIC 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
PHASE_FIELD 
 
 
+ 
 
 
 
 
 
VISCO 
 
 
+ 
 
 
 
 
 
*ELASTICLT 
 
 
+ 
 
+ 
 
+ 
 
SDA 
 
 
 
 
+ 
 
 
(+) 
*MISES 
 
+ 
+ 
 
+ 
 
+ 
+ 
*ISODAMAGE 
 
 
+ 
 
+ 
 
+ 
+ 
*MICRODAMAGE 
 
 
+ 
 
+ 
 
+ 
+ 
*RCBEAM 
+ 
+ 
 
 
 
 
 
 
*RESHEET 
 
 
 
 
+ 
 
 
 
*NLSLAB 
 
 
 
 
 
+ 
 
 
*RCSHELL 
 
 
 
 
 
 
+ 
 
*SPRING 
 
 
 
+ 
 
 
 
 
*BOND 
 
 
 
 
+ 
 
 
 
The material types are used with examples (see Section 5) as listed in the following:
3.1 
3.2 
3.4 
4.1 
4.2 
4.3 
4.4 
4.5 
4.6 
4.8 
4.9 
5.2 
X.X 
5.3 
6.2 
6.3 
6.4 
7.1 
7.2 
7.5 
7.6 
8.1 
8.2 
8.3 
8.4 
9.1 
9.2 
9.3 
9.4 
9.5 
10.1 
10.2 

*ELASTIC 
 
 
 
 
 
 
 
 
 
 
 
+ 
 
 
 
 
 
 
 
 
 
+ 
 
+ 
 
+ 
+ 
+ 
 
 
+ 
 
PHASE_FIELD 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
VISCO 
 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
*ELASTICLT 
 
 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
 
 
 
 
 
 
 
 
+ 
SDA 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
 
 
 
 
 
 
 
 
 
 
 
*MISES 
 
 
+ 
 
 
 
 
 
 
 
 
 
+ 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
*ISODAMAGE 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
+ 
 
+ 
+ 
 
 
 
 
 
+ 
 
 
 
 
 
 
+ 
*MICRODAMAGE 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
*RCBEAM 
 
 
 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
*RESHEET 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
*NLSLAB 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
+ 
 
 
*SPRING 
 
 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
*BOND 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
+ 
+ 
 
 
 
 
 
 
 
Each material type keyword has its specific data lines which are described in the following.
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The data line describes the following properties
, 
, 

with

Young’s modulus 

Poisson’s ratio 

thermal expansion coefficient 
A given date line sequence is mandatory. Values have to be separated by commas. Trailing extra values or comment like strings ( "some comment") are ignored. The same remarks hold for all data lines of the following material type keywords.
Element output provides standard data, see Section 12.3.
*ELASTIC may have an option VISCO which allows for viscoelasticity of the KelvinVoigttype, see Book 3.2. This is currently implemented for elements of type T* only. This option requires two more items in the data line which now takes the form
, 
, 
, 
, 

with

Young’s modulus 

Poisson’s ratio 

thermal expansion coefficient 

creep coefficient 

creep time 
Element output provides standard data, see Section 12.3.
*ELASTIC may have a further option PHASE_FIELD which activates the phasefield approach for resolution of strain localizations, see Book 7.5.2. This is currently implemented for elements of type T* only. This option requires three more data in the data line which now takes the form
, 
, 
, 
, 
, 

with

Young’s modulus 

Poisson’s ratio 

thermal expansion coefficient 

fracture toughness 

characteristic length 

stress viscosity – might be necessary for convergence, see Book A.1 (currently trial and error, default should be 0!) 
Element output provides standard data, see Section 12.3, and additionally the value of damage variable as last item of integration point data lines.
The options VISCO and PHASEFIELD cannot be combined.
The data line describes the following properties
, 
, 
, 
, 
, 
, 

with

Young’s modulus 

Poisson’s ratio 

uniaxial tensile strength 

crack energy 

width of weak section – currently effective only for 1D material approach 
generally corresponds to crack band width (material property!) but must not 


residual crack traction related to uniaxial tensile strength in case of macro crack 

crack traction viscosity – might be necessary for convergence, see Book A.1 (currently trial and error, default should be 0!) 
*ELASTICLT has distinct states which are reported to the execution report, see Section 12.2, when a state change occurs
0 
uncracked 
1 
cracked loading branch 
2 
cracked unloading branch 
3 
crack closure 
4 
fully cracked with zero crack traction 
Element output provides standard data, see Section 12.3.
*ELASTICLT may have an option SDA which activates the strong discontinuity approach (SDA) to describe crack formation by allowing for displacement discontinuities instead of smeared cracks, see Book 7.7. This is appropriate for continuum elements of type C* only. This is currently implemented as fixed crack for element types CP* and under construction for C3D*. This option requires a modified data line
, 
, 
, 
, 
, 
, 
, 

with

Young’s modulus 

Poisson’s ratio 

uniaxial tensile strength 

crack energy 

shear retention factor 
as far as can be seen results are quite sensitive with respect to this factor, i.e. small values seem to be appropriate 


minimum deviation (angle degree unit) for secondary fixed cracking according to Rankine criterion 
prevents dual cracking 


stress viscosity – might be necessary for convergence, see Book A.1 (currently trial and error, default should be 0!) 

crack traction viscosity for discrete cracks – might be necessary for convergence, see Book A.1 (currently trial and error, default should be 0!) 
Regarding ordinary integration points the element output provides standard data, see Section 12.3. Regarding integration points along discontinuity lines, additional data lines are provided, see also Section 12.3.
The data line describes the following properties
, 
, 
, 
, 
, 
, 

with

Young’s modulus 

Poisson’s ratio, not used for 1D 

yield stress in case of uniaxial stress 

failure stress in case of uni axial stress 

strain corresponding to 

thermal expansion coefficient 

parameter to smooth transition in yield point – for 1D stressstrain only 
generally sharp transition, try in case of convergence problems 
Element output provides standard data, see Section 12.3, and additionally
for B* elements types 
longitudinal stresses at lower and upper edge as last two items of integration point data lines 
for other element types 
the value of the current yield stress as last item of integration point data lines 
The data line describes the following properties
, 
, 
, 
, 
, 
, 

, 
, 
or , 
, 

with

initial Young’s modulus 

Poisson’s ratio 

uniaxial compressive strength 

uniaxial tensile strength 

type of triaxial strength surface 
choose – other values reserved for further extensions 


biaxal compressive strength related to uniaxial compressive strength 

circumferential stress related to longitudinal stress (compression) of confined cylinder specimen 

longitudinal strength related to uniaxial compressive strength of confined cylinder specimen under the condition 

regularization type 
: no regularization 

: gradient damage 

: crack band 


characteristic length for 

cack energy for – be careful with units! 
value is ignored for 


stress viscosity – might be necessary for convergence (currently trial and error, default should be 0!) 

crack traction viscosity for smeared cracks / SDA – might be necessary for convergence (currently trial and error, default should be 0!) 
Some care has to be taken in choosing the relations of , , and the value of . There might be unfeasible choices.
As an example with units [MN,m]
36300.,0.2, 40.,3.5, 1,1.2,0.2,2.0, 2,150.e6, 0., 0.
should make sense, e.g., for C40 according to MC2010.
Element output provides standard data, see Section 12.3, and additionally the value of isotropic damage as last item of integration point data lines.
The data line describes the following properties
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 

with

initial Young’s modulus 


Poisson’s ratio 


type of triaxial strength surface 

choose – other values reserved for further extensions 


uniaxial tensile strength 


a measure of uniaxial compressive strength related to uniaxial tensile strength 

this does not exactly reproduce the ratio, some inverse trial and error has to be applied to calibrate for a target 


currently not used, set – reserved for further extensions 


currently not used, set – reserved for further extensions 


regularization type 

: no regularization 

: crack band 


cack energy for – be careful with units! 

value is ignored for 


stress viscosity – might be necessary for convergence (currently trial and error, start with 0.0!) 


crack traction viscosity for smeared cracks / SDA – might be necessary for convergence (currently trial and error, start with 0.0!) 
As an example with units [MN,m]
363000., 0.20, 2, 3.0, 13.0, 0., 0., 0, 150.e06, 0., 0.
should make sense, e.g., for C40 according to MC2010.
Element output provides standard data, see Section 12.3, and additionally an averaged damage value over all microplanes of an integration point.
This must be combined with geometric reinforcement data defined in a *BEAM SECTION, see Section 10.6. The first data line describes the following concrete properties
, 
, 
, 
, 
, 





with

Young’s modulus 

compressive strength 

strain corresponding to compressive strength 

ultimate strain in case of uniaxial stress 

nominal tensile strength – for tension stiffening 
value comes only into play if tension stiffening is activated in *BEAM SECTION, see Section 10.6 


number of layers for integration of nonlinear stressstrain relation 
uses a linear relation without tension 

is mandatory to compute creep of concrete 

is generally used for nonlinear uniaxial concrete behavior 


thermal expansion coefficient 

creep coefficient 

creep time 

tensile strength – to consider concrete tensile strength in momentcurvature relations 
value is generally set to 0 according to common standards 
Tensile strength values and are used in different contexts and may be chosen independent from each other.
The second data line describes the reinforcing steel properties and is the same as for the *MISES data line.
Element output provides standard data for beam elements, see Section 12.3, and additionally edge strains [‰]: concrete edge strain at the compressed edge and strain of reinforcement with the largest lever arm at the tension edge.
This material type provides a reinforcement like plane sheet with uniaxial Mises elastoplasticity. The data line describes the following properties
, 
, 
, 
, 
, 

with

Young’s modulus 

orientation of reinforcement with respect to global direction in degrees 

yield strength in case of uniaxial stress 

failure strength in case of uniaxial stress 

strain corresponding to 

thermal expansion coefficient 
which to a large degree corresponds to the *MISES data line but be aware of the second item .
Only one data line is allowed corresponding to one reinforcement sheet. Further reinforcement sheets have to be defined with further *RESHEET material sections.
Element output provides standard data for 2D continuum elements, see Section 12.3.
This material type provides a bilinear momentcurvature relation for usage with Kirchhoffslabs. This includes elastoplastic behavior with unloading, i.e. elastic behavior of plastic cross sections prior to unloading. As slabs are statically indeterminate internally an elastoplastic behavior should not be expected in a straightforward way. The data line describes the following properties
, 
, 
, 
, 
, 
, 
, 
, 

with

initial bending stiffness in global direction 

initial bending stiffness in global direction 

final / yieldmoment of initial branch in global direction 

final / yield moment of initial branch in global direction 

hardening bending stiffness in global direction 

hardening bending stiffness in global direction 

final / ultimatemoment of hardening branch in global direction 

final / ultimate moment of hardening branch in global direction 

factor for twisting stiffness 
This is applied with absolute values for both positive moments (lower side tension) and negative moments (upper side tension) in the same way. Different definitions for positive and negative moments can be given with an expanded data line
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 
, 

whereby the upper index indicates positive parameters and negative parameters. See also the Book Sections 9.8.2, 9.8.3 for a further specification of these values.
Element output provides standard data for slabs, see Section 12.3.
This material type is appropriate for the continuum based shell with element type SH4 and must be combined with geometric reinforcement data defined in a *SHELL SECTION, see Section 10.7. The first seven items of the following data line correspond to the *MISES data line to be applied to uniaxial reinforcement behavior. The last item refers to a biaxial material law.
, 
, 
, 
, 
, 
, 
, 

with

Young’s modulus 

Poisson’s ratio, not used for 1D 

yield stress in case of uniaxial stress 

failure stress in case of uni axial stress 

strain corresponding to 

thermal expansion coefficient 

parameter to smooth transition in yield point – for 1D stressstrain only 
generally sharp transition, try in case of convergence problems 


name of a material of type *ELASTICLT or *ISODAMAGE or *MICRODAMAGE 
the respective material has to be explicitly defined with a material type specification 
Element output provides standard data for shells, see Section 12.3.
This material type provides a force depending on a relative displacement . This is basically described by cubic splines. It behaves in the same way in the negative and positive range. The data line describes the following properties
, 
, 
, 
, 
, 
, 

with

currently not used 

prescribed relative displacement 

force prescribed with 
for 


prescribed relative displacement, 

force prescribed with 
for 


end of starting range of relative displacement with linear stiffness up to 
may be set to starting with a cubic spline with initial slope 


initial constant stiffness for 
In case of decreasing the same force path is followed in reverse direction as for increasing .
Element output provides standard data for springs, see Section 12.3.
*BOND is an extension of *SPRING. It has the same behavior in case of loading, i.e. increasing . But regarding unloading with decreasing this type *BOND follows a ‘damage’characteristic, i.e. a linear path from largest in the current loading path to . The relation moves on this linear path as long as including a sign reversal where necessary. The loading path is continued like *SPRING in case . This increases directly connected to , i.e. is a state variable.
First data line describes the following properties
, 

with

currently not used 

linear stiffness related to lateral relative displacements of connected parts 
connected parts are generally a bulk material (e.g. concrete) and an embedded reinforcement 

in order to prevent a mutual penetration this should be a relatively high value with respect to the implied penalty method 

to check the relative lateral displacements see following output description 
The second data line is same as for *SPRING.
Element output provides standard data for bond elements, see Section 12.3.
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