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/FAIL/PUCK - Puck Composite Failure Model

Description

Describes the Puck failure model.

Format

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

/FAIL/PUCK/mat_ID/unit_ID

p+12

p-12

p-22

symbol_tmax

Ifail_sh

Ifail_so

Optional line:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

fail_ID

 

 

 

 

 

hmtoggle_plus1Flag Definition

Field

Contents

SI Unit Example

mat_ID

Material identifier

(Integer, maximum 10 digits)

 

unit_ID

Optional unit identifier

(Integer, maximum 10 digits)

 

Longitudinal tensile strength

Default = 1030  (Real)

symbol_Pa

Transverse tensile strength

Default = 1030  (Real)

symbol_Pa

Shear strength

Default = 1030  (Real)

symbol_Pa

Longitudinal compressive strength

Default = 1030  (Real)

symbol_Pa

Transverse compressive strength

Default = 1030  (Real)

symbol_Pa

p+12

Failure envelope factor 12 (+)

Default = 0  (Real)

 

p-12

Failure envelope factor 12 (-)

Default = 0  (Real)

 

p-22

Failure envelope factor 22 (-)

Default = 0  (Real)

 

symbol_tmax

Dynamic time relaxation (Comment 5)

Default = 1030  (Real)

symbol_S_unit

Ifail_sh

Shell failure model flag

Default = 1  (Integer)

= 1: Shell is deleted, if damage is reached for one layer.

= 2: Shell is deleted, if damage is reached for all shell layers.

 

Ifail_so

Solid failure model flag

Default = 1  (Integer)

= 1: Solid is deleted, if damage is reached for one integration point of solid.

 

fail_ID

(Optional) Failure criteria identifier (Comment 4)

(Integer, maximum 10 digits)

 

hmtoggle_plus1Example (Composite)

Strength () are taken from following tests. m1 is fiber direction.

fail_puck_example

#RADIOSS STARTER

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

/UNIT/1

unit for mat and failure

#              MUNIT               LUNIT               TUNIT

                  g                  mm                  ms

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

#-  1. MATERIALS:

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

/MAT/COMPSH/1/1

composite example

#              RHO_I

               .0015

#                E11                 E22                NU12     Iform                           E33

              114000                9650                .025         0                             0

#                G12                 G23                 G31              EPS_f1              EPS_f2

                6000                6000                6000                   0                   0

#             EPS_t1              EPS_m1              EPS_t2              EPS_m2                dmax

                   0                   0                   0                   0                   0

#              Wpmax               Wpref      Ioff                         ratio

                   0                   0         4                             0

#                  b                   n                fmax

                   0                   0                   0

#            sig_1yt             sig_2yt             sig_1yc             sig_2yc               alpha

                1E30                1E30                1E30                1E30                   0

#           sig_12yc            sig_12yt                c_12          Eps_rate_0       ICC

                1E30                1E30                   0                   0         0

#          GAMMA_ini           GAMMA_max               d3max

                   0                   0                   0

#  Fsmooth                Fcut

         0                   0

/FAIL/PUCK/1/1

#           Sigma1_T            Sigma2_T            Sigma_12            Sigma1_C            Sigma2_C

                1720                55.2                 103                 765                 503

#               P+12                P-12                P-22             Tau_max  Ifail_sh  Ifail_so

                   0                   0                   0                .005         1         0

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

#enddata

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

hmtoggle_plus1Comments
1.This failure model is available for Shell and Solid.
2.The failure mode criteria is written as:
Fiber fraction failure:

Tensile fiber failure mode:

Compressive fiber failure mode:

Inter fiber failure:

Mode A  if :

fail_puck_modeA

Mode C  if :

fail_puck_modeC

Mode B

fail_puck_modeB

If the damage parameter is ef > 1.0, the stresses are decreased by using an exponential function to avoid numerical instabilities. A relaxation technique is used by decreasing the stress gradually:

With,

Where,

t is the time,

tr is the start time of relaxation when the damage criteria is assumed,

symbol_tmax is the time of dynamic relaxation,

is the stress components at the beginning of damage.

3.The damage value, D is 0 < D < 1. The status for fracture is:
Free, if 0 < D < 1
Failure, if D =1

with anim_shell_dam_puck. This damage value shows with /ANIM/BRICK/DAMA or /ANIM/SHELL/DAMA.

4.The fail_ID is used with /STATE/BRICK/FAIL and /INIBRI/FAIL. There is no default value. If the line is blank, no value will be output for failure model variables in the /INIBRI/FAIL (written in .sta file with /STATE/BRICK/FAIL option).
5.The value of symbol_tmax determines a period of time after failure criterion is reached when the stress in failed element is gradually reduced to zero, then the element is deleted. This is necessary to avoid instability coming from a sudden element deletion and failure "chain reaction" in the neighboring elements. With this value, elements will not be deleted, even if the failure criterion is reached. Normal value of symbol_tmax is 10 times higher than the actual times step should be set in the card directly.