(*syntax*)

`TENCRV`specifies a predefined tension softening function [Fig.6.4]. [*curve*`LINEAR`] Beyond the tensile strength*f*_{t}the shape of these curves is like the tension softening curves for the multi-directional fixed crack models. See §20.1.1 for background theory. *Tensile parameters.*- If you specified the basic properties via the CEB-FIP Model Code 1990
[§6.2.1.1], CEB-FIP Model Code 2010 [§6.2.1.2],
Eurocode 2 EN 1992-1-1 [§6.2.1.3],
ACI 209R-92 [§6.2.1.4], AASHTO [§6.2.1.5],
JCI [§6.2.1.6],
JSCE [§6.2.1.7], KCI [§6.2.1.8], or
NEN 6720/A4 [§6.2.1.9] code regulations
then DIANA can determine all tensile
parameters without further input.
Else you must specify the tensile parameters,
depending on the softening function, as outlined in the following.

**Elastic** (*syntax*)

`ELASTI`-
for elastic behavior in tension, i.e., no cracking
[Fig.6.4a].

**Ideal and brittle** (*syntax*)

`CONSTA`-
for ideal behavior [Fig.6.4b].
`BRITTL`-
for brittle behavior
[Fig.6.4c].
`TENSTR`-
is the tensile strength*ft**f*_{t}. `RESTST`-
is the residual tensile strength, below which the tensile strength stress will not drop for large strains in case of brittle behavior.*sigres* `TEM`- influence by temperature:
to*a1*are tempreatures*an**T*. The temperature-time dependency must be specified via input table `'TEMPER'`[§1.2.1]. `CON`- influence by concentration:
to*a1*are concentrations*an**C*. The concentration-time dependency must be specified via input table `'CONCEN'`[§1.2.2]. `MAT`- influence by maturity:
to*a1*are maturity variables*an**M*. The maturity-time dependency must be specified via input table `'MATURI'`[§1.2.3]. `PRE`- influence by pressure:
to*a1*are pressures*an**P*. The pressure-time dependency must be specified via input table `'PRESSU'`[§1.2.4]. `TST`- influence on the tensile strength:
to*ft1*are the*ftn**f*_{t}values for the ambient values to*a1*.*an* `USRTST`-
tensile strength determined
via subroutine
`USRTST`[§13.3.5].

**Linear tension softening - based on ultimate strain** (*syntax*)

`LINEPS`-
for ultimate strain based linear softening [Fig.6.4d].
`TENSTR`-
is the tensile strength*ft**f*_{t}. `EPSULT`-
is the Mode-I ultimate tensile strain*eu*as depicted in Figure 6.4d. `RESTST`-
is the residual tensile strength, below which the tensile strength stress will not drop for large strains.*sigres* `TEM`- influence by temperature:
to*a1*are tempreatures*an**T*. The temperature-time dependency must be specified via input table `'TEMPER'`[§1.2.1]. `CON`- influence by concentration:
to*a1*are concentrations*an**C*. The concentration-time dependency must be specified via input table `'CONCEN'`[§1.2.2]. `MAT`- influence by maturity:
to*a1*are maturity variables*an**M*. The maturity-time dependency must be specified via input table `'MATURI'`[§1.2.3]. `PRE`- influence by pressure:
to*a1*are pressures*an**P*. The pressure-time dependency must be specified via input table `'PRESSU'`[§1.2.4]. `TST`- influence on the tensile strength:
to*ft1*are the*ftn**f*_{t}values for the ambient values to*a1*.*an* `EPU`- influence on the Mode-I ultimate tensile strain:
to*eu1*are the*eun*values for the ambient values to*a1*.*an* `USRTST`-
tensile strength determined
via subroutine
`USRTST`[§13.3.5]. `USREPU`-
Mode-I ultimate tensile strain determined
via subroutine
`USREPU`[§13.3.6].

**Tension softening curves - based on fracture energy** (*syntax*)

`LINEAR`-
for linear softening [Fig.6.4e].
`EXPONE`-
for exponential softening [Fig.6.4f].
`HORDYK`-
for softening according to
Hordijk et al. [Fig.6.4g].
`JSCESO`-
for softening according to Japan Society of Civil Engineers
(JSCE) [71]
[Fig.6.4i].
`TENSTR`-
is the tensile strength*ft**f*_{t}. `GF1`-
is the Mode-I fracture energy*gf1**G*_{f}^{I}. The linear, exponential, and Hordijk softening curves also require the crack bandwidth *h*. By default DIANA assumes a value of *h*related to the area or the volume of the element. You may overrule the default by specifying the crack bandwidth explicitly via the `CRACKB`input data item [§6.3].*Note that combinations of a small Mode-I fracture energy**G*_{f}^{I}and a large crack bandwidth *h*may lead to a decreased tensile strength *f*_{t}. For direct input of `GF1`and`TENSTR`this is checked and warnings will be issued. However, for input of*G*_{f}^{I}and *f*_{t}with ambient influence no warning is issued and the tensile strength *f*_{t}is lowered without notice. `RESTST`-
is the residual tensile strength, below which the tensile strength stress will not drop for large strains in case of linear softening, exponential softening, or softening according to Hordijk et al.*sigres* `TEM`- influence by temperature:
to*a1*are tempreatures*an**T*. The temperature-time dependency must be specified via input table `'TEMPER'`[§1.2.1]. `CON`- influence by concentration:
to*a1*are concentrations*an**C*. The concentration-time dependency must be specified via input table `'CONCEN'`[§1.2.2]. `MAT`- influence by maturity:
to*a1*are maturity variables*an**M*. The maturity-time dependency must be specified via input table `'MATURI'`[§1.2.3]. `PRE`- influence by pressure:
to*a1*are pressures*an**P*. The pressure-time dependency must be specified via input table `'PRESSU'`[§1.2.4]. `TST`- influence on the tensile strength:
to*ft1*are the*ftn**f*_{t}values for the ambient values to*a1*.*an* `GF1`-
influence on the Mode-I tensile fracture energy:
to*gf11*are the*gf1n**G*_{f}^{I}values for the ambient values to*a1*.*an* `USRTST`-
tensile strength determined
via subroutine
`USRTST`[§13.3.5]. `USRGF1`-
Mode-I tensile fracture energy determined
via subroutine
`USRGF1`[§13.3.7].

**Multi-linear** (*syntax*)

A multi-linear diagram fully describes the stress-strain relationship,
therefore input of the tensile strength
*f*_{t}

`MULTLN`-
for a multi-linear diagram [Fig.6.4h].
`TENPAR`-
are the points of the multi-linear diagram:
*n*pairs of values ( , ); ( 1 *n*100) ...*s0*are the tensile stresses*sn*, ...*e0*are the corresponding total strains*en*. In general the curve should start with a linear elastic slope from the origin to the tensile strength *f*_{t}as in Figure 6.4h.

**JSCE tension stiffening** (*syntax*)

`JSCETS`- for Japan Society of Civil Engineers (JSCE) tension stiffening [71]
[Fig.6.4j]:
= *f*_{t}(/)^{c}(6.3)

`TENSTR`-
is the tensile strength*ft**f*_{t}. `EPSTU`-
is the end of plateau strain*etu*. [ = 0.0002 ] `CPOWER`-
is the power*c**c*. [ *c*= 0.4]

**CEB-FIP Model Code 1990** (*syntax*)

`MC1990`- for tension softening according to Paragraph 2.1.4.4.2 of the European CEB-FIP Model Code 1990 [26] [Fig.6.4k]:
`TENSTR`is the tensile strength*ft**f*_{t}. `GF1`is the Mode-I fracture energy*gf1**G*_{f}^{I}. By default DIANA assumes a value of the crack bandwidth *h*related to the area or the volume of the element. You may overrule the default by specifying the crack bandwidth explicitly via the `CRACKB`input data item [§6.3].*Note that combinations of a small Mode-I fracture energy**G*_{f}^{I}and a large crack bandwidth *h*may lead to a decreased tensile strength *f*_{t}. This is checked and warnings will be issued. `DMAX`is the maximum aggregate size of concrete in mm. Possible maximum aggregate sizes are 8, 16, or 32 mm. [*dmax**dmax*= 16mm]

**CEB-FIP Model Code 2010** (*syntax*)

`MC2010`- for tension softening according to Paragraph 5.1.8.2 of the European CEB-FIP Model Code 2010 [27] [Fig.6.4l]:
`TENSTR`is the tensile strength*ft**f*_{t}. `GF1`is the Mode-I fracture energy*gf1**G*_{f}^{I}. By default DIANA assumes a value of the crack bandwidth *h*related to the area or the volume of the element. You may overrule the default by specifying the crack bandwidth explicitly via the `CRACKB`input data item [§6.3].*Note that combinations of a small Mode-I fracture energy**G*_{f}^{I}and a large crack bandwidth *h*may lead to a decreased tensile strength *f*_{t}. This is checked and warnings will be issued.

**CEB-FIP fiber reinforced concrete model** (*syntax*)

`FRCCON`- for the fiber reinforced concrete modelas defined by the CEB-FIB working groups [Fig.6.4m]. The model can be either specified as function of the total strain or as function of the crack opening.
`FRCEPS`is the tensile strength*ft**f*_{t}, and*fr1*represent the first reference point in the stress-strain curve ( ,*epsr1**f*_{R1}), and*fr3*represent the second reference point in the stress-strain curve ( ,*epsr3**f*_{R3}), and is the ultimate strain*epsu*[Fig.6.4m]. `FRCCMD`is the tensile strength*ft**f*_{t}, and*fr1*represent the first reference point in the stress-crack opening curve (*cmodr1**cmd*_{R1},*f*_{R1}), and*fr3*represent the second reference point in the stress-crack opening curve (*cmodr3**cmd*_{R3},*f*_{R3}), and is the ultimate crack opening*cmodu**cmd*_{u}. The crack strain is obtained by dividing the crack opening by the crack bandwidth *h*. By default DIANA assumes a value of *h*related to the area or the volume of the element. You may overrule the default by specifying the crack bandwidth explicitly via the `CRACKB`input data item [§6.3].

6.2.2.2 User-supplied Tension Softening

(*syntax*)

`USRCRV`-
specifies that the function of the tensile stress is determined via a
user-supplied subroutine [§13.3.1].
`USRPAR`-
is a series of parameters of the user-supplied curve which DIANA passes to the subroutine.*usrpar*

First ed.

Copyright (c) 2015 by TNO DIANA BV.