/MAT/LAW10

Block Format Keyword

/MAT/LAW10 - Rock-Concrete Material

Description

This law, based on Drücker-Prager yield criteria, is used to model materials with internal friction such as rock-concrete. The plastic behavior of these materials is dependent on the pressure in the material (Comment 1). This law is similar to LAW21 (/MAT/DPRAG); the only difference being that in this law, the pressure is defined as a cubic function of volumetric strain, and hence requires the input of certain coefficients (Comment 2). This law is compatible only with solid elements.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW10/mat_ID/unit_ID or /MAT/DPRAG1/mat_ID/unit_ID
mat_title

E
A0		A1		A2		Amax
C0		C1		C2		C3
min		Pext
B

Field	Contents	SI Unit Example
mat_ID	Material identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
mat_title	Material title (Character, maximum 100 characters)
	Initial density (Real)
E	Young’s modulus (Real)
	Poisson’s ratio (Real)
A0	Yield criteria coefficient (Real)
A1	Yield criteria coefficient (Real)
A2	Yield criteria coefficient (Real)
Amax	Yield criteria limit (von Mises limit) (Real)
C0	EOS coefficient (Real)
C1	EOS coefficient (Comment 4) (Real)
C2	EOS coefficient (Real)
C3	EOS coefficient (Real)
	Minimum pressure ( < 0 ) Default = -1030 (Real)
Pext	External pressure (Comment 3) (Real)
B	Unloading bulk modulus (Comment 4) Default = C1 (Real)
	Maximum compression (Comment 5) (Real)

#RADIOSS STARTER

/UNIT/1

unit for mat

g cm mus

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#- 2. MATERIALS:

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/MAT/LAW10/1/1

Concrete

# RHO_I

2.4

# E NU

.576 .25

# A0 A1 A2 Amax

9.72E-10 4.32E-5 .48 .013

# C0 C1 C2 C3

0 .256 .256 1

# P_min P_ext

-1E-20 0

# B Mu_max

.115 .44

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#ENDDATA

/END

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

1.	Pressure in the material is calculated from the following equation. Coefficient C0, C1, C2, and C3 should be provided as an input.

Loading:

Unloading:

If < , then unloading bulk modulus B is used for the unloading/reloading path.

For each over , the unloading path is the same as the loading path.

mat_law10A

2.	Drücker-Prager yield criteria is given by:

mat_law10B

A1 = A2 = 0 means that yield criteria is von Mises ().

Polynomial expression should have at least one root and should be increasing.

External pressure is needed in case of relative pressure formulation. In this specific case yield criteria and energy integration require total pressure value. RADIOSS outputs a pressure which is relative to Pext. You can conclude the total pressure value from P = Pext +

where,

is EOS calculation. Total pressure limit is concluded from Plim = Pext +

lim.

If Pext = 0, then output result is a total pressure: P = and Plim = lim.

4.	Tensile bulk modulus, C1, must be positive.

5.	If B = 0 and = 0, the unloading path and the loading path are the same.

If B = 0 or ≠ 0, the default value for B is .

If or = 0, the default value for is .

loading_unloading

If B is defined, then it must be greater than any slope in [0; ].

/MAT/LAW10 (DPRAG1)

/MAT/LAW10 (DPRAG1)

/MAT/LAW10 (DPRAG1)

Format