9.3.2 Plasticity

Von Mises plasticity and hardening models are available for embedded reinforcements. Temperature influence on the plasticity is also possible.

(syntax)

YIELD

species the Von Mises yield criterion.

YLDVAL

sy is the yield stress $\sigma_{\mathrm{y}}^{}$.

NOBOND

indicates that the reinforcement is not bonded to its mother elements. This option only applies for post-tensioned reinforcement [§9.3.3].

HARDEN

specifies the hardening hypothesis: WORK for work hardening or STRAIN for strain hardening.

HARDIA

specifies a hardening diagram: sy1 ...syn (n $\leq$ 25)are the yield stresses $\sigma_{\mathrm{y}}^{}$ and k1 to kn the corresponding equivalent plastic strains $\kappa$ [Fig.16.3b].

CORROS

specifies corrosion influence: t1 ...tn ( 2 $\leq$ n $\leq$ 500)are times t for which corrosion influence is specified. Values f1 ...fn are the reduction factors f ( 0 $\leq$ f $\leq$ 1)for the reinforcement cross-section at the corresponding times. DIANA applies linear interpolation between the specified time points. The corrosion option can only be used in physical nonlinear analysis with time steps.

USRYOU

specifies that the temperature influence on Young's modulus is determined via a user-supplied subroutine [§10.1.1]. DIANA passes the keyword usrkey to argument usrkey of this subroutine. For reinforcements, concentration and maturity data is not available in this routine.

SQVCRV

USRCRV specifies that the temperature influence on the plasticity criterion is determined via the user-supplied subroutine USRCRV [§10.3]. DIANA passes the parameters usrpar to argument usrpar of this subroutine. For reinforcements, concentration and maturity data is not available in this routine.

The example of Figure 16.4 holds for hardening plasticity of reinforcements.

9.3.2.1 Temperature Influence

In nonlinear analysis, the ambient temperature may influence the yield stress of embedded reinforcements. The temperature-time dependency must be specified via input table 'TEMPER' [§1.2].

(syntax)

TEMYLD

specifies temperature influence on the yield stress $\sigma_{\mathrm{y}}^{}$. Values te1 to ten (n $\leq$ 15)are temperatures T. Values sy1 to syn are the yield stresses for the corresponding temperatures.

(file.dat)

'MATERI'
 1   YOUNG  210000.
     TEMYOU 0. 210000.   150. 210000.    750. 0.
     TEMALP 0. 1.2E-5    900. 1.2E-5
     YIELD  VMISES
     YLDVAL 400.
     TEMYLD 0. 400.      300. 400.       750. 0.