/PROP/TYPE18 (INT

It can be used for deep beam cases (short beams). Beam section and position of integration points can be either used as predefined or prescribed directly.

Format

(1)	(2)	(3)	(5)
/PROP/TYPE18/`prop_ID`/`unit_ID` or /PROP/INT_BEAM/`prop_ID`/`unit_ID`
`prop_title`
`I`_sect	`I`_smstr
`d`_m		`d`_f
`NIP`	`I`_ref	`Y`₀	`Z`₀

If NIP > 0, add NIP cards defining the subsection parameters (each integration point per line)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
`Y`_i		`Z`_i		`Area`

If I_sect > 0, add following 2 lines

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
`NITR`		`L1`		`L2`
Blank Line

Add flag for rotational DOF for the beam nodes.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
$ω_{DOF}$

Definitions

Field	Contents	SI Unit Example
`prop_ID`	Property identifier (Integer, maximum 10 digits)
`unit_ID`	Unit Identifier (Integer, maximum 10 digits)
`prop_title`	Property title (Character, maximum 100 characters)
`I`_sect	Section type. 5 =0 (Default) Integrated beam. =1 Predefined rectangular section. =2 Predefined circular section. (Integer)
`I`_smstr	Small strain option flag. =0 (Default) Set to 4. =1 Small strain formulation from t = 0. =4 Full geometric nonlinearities. (Integer)
`d`_m	Beam membrane damping. Default = 0.00 (Real)
`d`_f	Beam flexural damping. Default = 0.01 (Real)
`NIP`	Number of integration points (subsections). Only for `I`_sect =0; otherwise, `NIP`=0. (Integer)
`I`_ref	Subsection center reference flag. Only for `I`_sect =0. =0 (Default) Subsection center is calculated as a barycenter of the integration points. =1 Subsection center is defined by using local coordinates (`Y`₀ and `Z`₀). (Integer)
`Y`₀	Local Y coordinate of the section center. Only for `I`_sect =0. (Real)	$[m]$
`Z`₀	Local Z coordinate of the section center. Only for `I`_sect =0. (Real)	$[m]$
`Y`_i	Local Y coordinate of the integration point. (Real)	$[m]$
`Z`_i	Local Z coordinate of the integration point. Only for `I`_sect =0. (Real)	$[m]$
`Area`	Area of the subsection. Only for `I`_sect =0. (Integer)	$[m^{2}]$
`NITR`	`NITR*NITR` is the number of integration points in predefined section for `I`_sect > 0. (Integer)
`L1`	First size of the predefined section for `I`_sect > 0. 5 (Real)
`L2`	Second size of the predefined section for `I`_sect > 0. 5 (Real)
$ω_{D O F}$	Rotation DOF code of nodes 1 and 2 (see detail input below). (6 Booleans)

Detail of Rotation DOF Input Fields for Nodes 1 and 2

(1)-1	(1)-2	(1)-3	(1)-4	(1)-5	(1)-6	(1)-7	(1)-8	(1)-9	(1)-10
			$ω_{X 1}$	$ω_{Y 1}$	$ω_{Z 1}$		$ω_{X 2}$	$ω_{Y 2}$	$ω_{Z 2}$

Definitions

Field	Contents	SI Unit Example
$ω_{X 1}$	= 1 Rotation DOF about X at node 1 is released. (Boolean)
$ω_{Y 1}$	= 1 Rotation DOF about Y at node 1 is released. (Boolean)
$ω_{Z 1}$	= 1 Rotation DOF about Z at node 1 is released. (Boolean)
$ω_{X 2}$	= 1 Rotation DOF about X at node 2 is released. (Boolean)
$ω_{Y 2}$	= 1 Rotation DOF about Y at node 2 is released. (Boolean)
$ω_{Z 2}$	= 1 Rotation DOF about Z at node 2 is released. (Boolean)

Example

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/2
unit for prop
                  Mg                  mm                   s
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/TYPE18/4/2
Integrated beam - bXh=10X10 with 4 integration points (subsections)
#    Isect   Ismstmr
         0         0
#                 dm                  df
                   0                   0
#      NIP      Iref                  Y0                  Z0
         4         1                   0                   0
#                  Y                   Z                Area
                 2.5                 2.5                  25
                 2.5                -2.5                  25
                -2.5                 2.5                  25
                -2.5                -2.5                  25
# OmegaDOF                                                                        
   000 000
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Example

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/2
unit for prop
                  Mg                  mm                   s
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/TYPE18/4/2
Integrated beam  - 4 integration points in predefined section bXh=10X10
#    Isect   Ismstmr
         1         0
#                 dm                  df
                   0                   0
#      NIP      Iref                  Y0                  Z0
         0         1                   0                   0
#     NITR                            L1                  L2
         2                            10                  10

# OmegaDOF                                                                        
   000 000
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

Small strain formulation is activated from time t=0, if I_smstr =1. It may be used for a faster preliminary analysis because $Δ t$ is constant, but the accuracy of results is not ensured.
If I_smstr =1, the strains and stresses which are given in material laws are engineering strains and stresses. Time history output returns true strains and stresses.

Figure 1.
The cross-section of the element is defined using up to 100 integration points (Figure 2). The element properties of the cross-section, i.e. area moments of inertia and area, are computed by Radioss as:(1)
$A = \sum A_{i} = \sum (d y_{i} d z_{i})$
(2)
$I_{Z} = \sum A_{i} (y_{i}^{2} + \frac{1}{12} d y_{i}^{2})$
(3)
$I_{Y} = \sum A_{i} (z_{i}^{2} + \frac{1}{12} d z_{i}^{2})$
It can be used for deep beam cases (short beams). The use of several integration points in the section allows to get an elasto-plastic model in which von Mises criteria is written on each integration point and the section can be partially plastified contrary to the classical beam element (TYPE3). Compatible with material LAW1, LAW2, and LAW36. However, as the element has only one integration point in its length, it is not recommended to use a single beam element per line of frame structure in order to take into account the plasticity progress in length, as well as in depth.

Figure 2. Cross-section Definitions in the Integrated Beam
Predefined cross-sections are available (circular or rectangular). Number of integration point in the section is stated by NITR. Integration points are distributed uniformly across the section according to the section type and NITR.
For rectangular section: L1 is the rectangular size in Y-direction of the local beam coordinates system and L2 is the rectangular size in Z-direction.

For circular section: L1 is the radius.

Figure 3.

/PROP/TYPE18 (INT_BEAM)

Format

Definitions

Detail of Rotation DOF Input Fields for Nodes 1 and 2

Definitions

Example

Example

Comments