B.5.5 Interfaces

Via this concept you may specify material models for interface elements.

Interfaces				§9.3
no parameters

With further concepts you may specify material parameters for nonlinear elasticity, friction, bond-slip, cracking, or combined cracking-shearing-crushing.

B.5.5.1 Nonlinear Elasticity

For interface elements you may specify models for nonlinear elasticity.

Nonlinear elasticity
File stiffness diag normal dir	file	SIGDIS	tn un	§9.3.1.3
File stiffness diag tangnt dir	file	TAUDIS	tt ut	§9.3.1.3

B.5.5.2 Friction

For interface elements you may specify a Coulomb friction criterion with optional hardening and gapping [§9.3.4].

Frictional behavior		FRICTI		§9.3.4
Cohesion	c	FRCVAL	ch	§9.3.4
Tangent of friction angle	tan$\phi$	FRCVAL	tph	§9.3.4
Tangent of dilatancy angle	tan$\psi$	FRCVAL	tps	§9.3.4

No hardening
no parameters

Hardening diagram				§9.3.4
File cohesion hardening diag	file	HARDIA	ch up	§9.3.4
File friction hardening diag	file	FRCDIA	tph up	§9.3.4

No gap criterion
no parameters

Gap criterion				§9.3.4
no parameters

Brittle gapping		MODE2	0	§9.3.4
Tensile strength	ft	GAPVAL	ft	§9.3.4

Gapping+const shear retention		MODE2	1	§9.3.4
Tensile strength	ft	GAPVAL	ft	§9.3.4
Reduced stiffness		MO2VAL	mv2	§9.3.4

Gapping+aggregate interlock		MODE2	2	§9.3.4
Tensile strength	ft	GAPVAL	ft	§9.3.4
Compressive strength		MO2VAL	mv2	§9.3.4

B.5.5.3 Bond-slip

For interface elements you may apply a bond-slip model.

Bond-slip behavior				§9.3.3
no parameters

Doerr's model		BONDSL	1	§9.3.3
C	c	SLPVAL	c	§9.3.3
Shear slip at plateau	$\Delta$ut0	SLPVAL	ut0	§9.3.3

Noakowski's model		BONDSL	2	§9.3.3
A	a	SLPVAL	a	§9.3.3
B	b	SLPVAL	b	§9.3.3
Shear slip - curve truncation	$\Delta$ut0	SLPVAL	ut0	§9.3.3

Multi-linear model		BONDSL	3	§9.3.3
File bond-slip diagram	file	SLPVAL	tt ut	§9.3.3

B.5.5.4 Cracking

For interface elements you may apply a discrete cracking or a crack dilatancy model.

Discrete cracking.

For a discrete cracking model you must specify the tensile strength and the softening and unloading models.

Discrete Cracking				§9.3.2.1
Tensile strength	ft	DCRVAL	ft	§9.3.2.1

Brittle cracking		MODE1	0	§9.3.2.1
no parameters

Linear tension softening		MODE1	1	§9.3.2.1
Fracture energy	Gf	MO1VAL	gf	§9.3.2.1

Nonlinear tension softening		MODE1	2	§9.3.2.1
Fracture energy	Gf	MO1VAL	gf	§9.3.2.1

Multilinear tension softening		MODE1	3	§9.3.2.1
File tensile traction diagram	file	MO1VAL	tn un	§9.3.2.1

Secant mode I unloading		UNLO1	1	§9.3.2.1
no parameters

Elastic mode I unloading		UNLO1	2	§9.3.2.1
no parameters

Hysteresis mode I unload		UNLO1	3	§9.3.2.1
no parameters

Zero shear stiffn.aft crack		MODE2	0	§9.3.2.1
no parameters

Const shear stiffn.aft crack		MODE2	1	§9.3.2.1
Shear modulus crack dev.		MO2VAL	mv2	§9.3.2.1

Crack dilatancy.

For two-dimensional interface elements you may choose a model for crack dilatancy.

Crack dilatancy				§9.3.2.2
no parameters

Li's model		CRDILA	0	§9.3.2.2
Cube compressive strength	fcc	DILVAL	fcc	§9.3.2.2
Tensile strength	ft	DILVAL	ft	§9.3.2.2
Maximum aggregate size		DMAX	dmax	§9.3.2.2

Walraven's 2 phase model		CRDILA	1	§9.3.2.2
Cube compressive strength	fcc	DILVAL	fcc	§9.3.2.2
Tensile strength	ft	DILVAL	ft	§9.3.2.2
Maximum aggregate size		DMAX	dmax	§9.3.2.2

Bazant&Gambarova rough crack		CRDILA	2	§9.3.2.2
Cube compressive strength	fcc	DILVAL	fcc	§9.3.2.2
Tensile strength	ft	DILVAL	ft	§9.3.2.2
Maximum aggregate size		DMAX	dmax	§9.3.2.2

Walraven&Reinhardt interlck		CRDILA	3	§9.3.2.2
Cube compressive strength	fcc	DILVAL	fcc	§9.3.2.2
Tensile strength	ft	DILVAL	ft	§9.3.2.2
Maximum aggregate size		DMAX	dmax	§9.3.2.2

Gambarova&Karakoc rough crk		CRDILA	4	§9.3.2.2
Cube compressive strength	fcc	DILVAL	fcc	§9.3.2.2
Tensile strength	ft	DILVAL	ft	§9.3.2.2
Maximum aggregate size		DMAX	dmax	§9.3.2.2

Brittle cracking		MODE1	0	§9.3.2.2
no parameters

Linear tension softening		MODE1	1	§9.3.2.2
no parameters

B.5.5.5 Combined Cracking-Shearing-Crushing

For interface elements you may choose a model for combined cracking-shearing-crushing [§9.3.5].

Combined crack-shear-crush		COMBIF		§9.3.5
Tensile strength	ft	GAPVAL	ft	§9.3.5
Fracture energy	Gf	MO1VAL	gf1	§9.3.5
Cohesion	c	FRCVAL	ch	§9.3.5
Tangent of friction angle	tan$\phi$	FRCVAL	phi	§9.3.5
Tangent of dilatancy angle	tan$\psi$	FRCVAL	psi	§9.3.5
Residual friction coefficient	$\Phi_{{\mathrm{r}}}^{}$	FRCVAL	phir	§9.3.5
Confining normal stress psi=0	$\sigma_{{\mathrm{u}}}^{}$	FRCVAL	sigu	§9.3.5
Exponential degradation coeff.	$\delta$	FRCVAL	delta	§9.3.5
Cap crit. compres. strength	fc	CAPVAL	fc	§9.3.5
Shear traction control factor	Cs	CAPVAL	cs	§9.3.5
Compressive fracture energy	Gfc	MOCVAL	gfc	§9.3.5
Equiv. plastic relative disp.	$\kappa_{{\mathrm{p}}}^{}$	MOCVAL	kp	§9.3.5

Constant Mode II fract. energy
Fracture energy factor b	b	MO2VAL	gf2b	§9.3.5

Linear Mode II fracture energy
Fracture energy factor a	a	MO2VAL	gf2a	§9.3.5
Fracture energy factor b	b	MO2VAL	gf2b	§9.3.5