Lifting beam#

A lifting beam node is a custom node that models a complete lifting beam including trunnions and sling protectors.

image-20221105161718546

The properties of the lifting beam are read from a .liftingbeam.csv file. For each lifting beam a re-usable .csv file can be created.

Once available, the user only needs to select the appropriate .csv file and optionally define where the trunnions and/or sling protectors are.

Adding new lifting beam types to DAVE#

New lifting beam types can be added to DAVE by placing a .liftingbeam.csv file in one of the DAVE resource paths.

For a formal description of the DAVE .csv file format see the appendix of the Base_Extensions manual. A .csv file can be created with any text-editor. Excel can also export .csv files but when doing so make sure (and check) that it exports the file using a , as separator and not a ;. It is probably easiest to copy an existing file and edit that.

For lifting beams this file contains the following sections:

  • Properties of the trunnions

    • diameter

    • width

    • mass

    • visual (note 1)

      trunnion_dia, 500 # [mm]
trunnion_mass, 1.63 # [metric tonnes]
trunnion_width, 1800 # [mm]
trunnion_visual, res: EQ 180 trunnion.obj     # note, needs to be scaled and rotated to [m], origin at geometric center and beam in x-direction

    • Optionally a cog position can be defined for the trunnions that the user can move.

      # Optional settings
nonfixed_trunnion_cog, 1.1,2.2,3.3

    • Optionally an additional liftpoint can be defined to be added to non-fixed trunnions

      # Optional setting for additional liftpoint on trunnion
trunnion_additional_liftpoint_name, AdditionalLiftpoint, # can be anything
trunnion_additional_liftpoint_position, 1, -.1, 2   # position relative to trunnion origin
trunnion_additional_liftpoint_diameter, 300 # [mm]
trunnion_additional_liftpoint_direction, 0,1,0.5 # direction of axis of liftpoint

  • Properties of grommet protectors (If any)

    • Width (can be zero)

    • mass[mT] - the weight is modelled to be at the center of the two circles

    • radius

    • Elevation

    • Visual

      # -- grommet protector properties
gp_width, 1.4 # [m]
gp_mass, 0    # [mT]
gp_radius, 300 # [mm]
gp_elevation, 1.4 #  [m]
gp_visual, res: grommet_protector_eq180.obj # note, needs to be scaled and rotated to [m], see docs for info about origin and orientation

  • A table of slots in which a trunnion can be placed

    • Name

    • Location in x and z direction

      *Slots  # data-table defining positions of the slots
# Name     , x [mm] , z [mm]
Lower 1    , 5250   , -500
Lower 2    , 3650   , -500
Lower 3    , 2050   , -500
Lower 4    , -2050  , -500
Lower 5    , -3650  , -500
Lower 6    , -5250  , -500
Upper 1    , 4450   , 500
Upper 2    , 2850   , 500
Upper 3    , -2850  , 500
Upper 4    , -4450  , 500

  • Optional: A table of locations where a fixed trunnion is present. This places a standard (as define above) trunnion at that location

    • Name

    • Location in x and y direction

      *Trunnions # data-table defining positions of the trunnions
# Name          , x [mm] , z [mm]
Trunnion1      ,  0      , -1000
Side Trunnion A,  5500       , 0
Side Trunnion B, -5500       , 0

  • Optional: A table of locations where a fixed grommet protector is present. This places a standard (as define above) grommet protectors at that location

    • Name

    • Location in x

      *GrommetProtectors # data-table defining positions of the trunnions
# Name          , x [mm]
Protector1      ,  0      
Protector2      ,  5500      
Protector3      , -5500

  • Optional: Liftpoints: A table of additional lifpoints.

    • Name

    • Location (x,y,z)

    • Diameter

    • Direction

      *Liftpoints
# Name,         , x [mm]  , y [mm]  , z [mm] , diameter [mm], ux , uy , uz,
End A           , -6200   , 0       , -150      , 600        , -1 , 0  , 0
End B           ,  6200   , 0       , -150      , 600        ,  1 , 0  , 0

    note 1:needs to be scaled to [m] and rotated such that the origin is at geometric center and lifting-beam is in in x-direction

  • Optional: Frames: A table of additional frames - For example useful to use as connection points between beams.

    *Frames
# Name    , x , y , z , rx, ry, rz
Some_name , 1 , 2 , 3 , 70, 0 , 0

  • Visuals: Visuals used for the main steel of the lifting-beam

    • Resource and scale, rotation and offset properties

      *Visuals
# Name , resource               , off-x, off-y, off-z, rot-x, rot-y, rot-z, scale-x, scale-y, scale-z,,,
Visual1, res: cylinder 1x1x1.obj,-6,0,0               ,0,90,0               ,12,1.2,1.2,

  • Weights: Weights and weight distribution used for the main steel of the lifting-beam

    • Weight, CoG and footprint

      *Weights
#                                                                                                                                                    Note: interia is not used for statics
# 'Name',       'mass [mT]', 'Cog-x', 'Cog-y', 'Cog-z', 'footprint: elevation', 'footprint: aft', 'footprint: front', 'footprint: sb', 'footprint: ps', 'inertia: rxx', 'inertia: ryy', 'inertia: rzz'
EQ_main_steel,   17,           0       ,  0     ,  0     ,  0                    , -6              ,  6                ,   0           , 0              , 1             , 1             , 1

Visuals#

The visuals need to be saved in .obj format and need to be placed in any resource folder. Using a subfolder for every beam is a good idea.

The visuals for trunnions and grommet protectors can not be scaled, moved or rotated by DAVE. They therefore need to be supplied in the correct scale and orientation. For all DAVE visuals the unit is [m]

Axis system for Grommet-protectors#

For grommet protectors the Y-axis is perpendicular to the lifting beam and the Z-axis points upwards.

image-20221107093330403

Elevation such that the centerline of the circles is at z=0. In X and and Y direction the origin

image-20221117150745710

Axis system for Trunnions#

For trunnions the Y-axis is perpendicular to the lifting beam and the Z-axis points upwards.

In X and Z direction the origin is located at the center of the trunnion circles. In Y-direction the origin is located at the center.

image-20221117150154829

Example file#

# This is an example of a lifting beam
#
# The origin of the liftingbeam is its geometrical center
#
# General settings
trunnion_dia, 500 # [mm]
trunnion_mass, 1.63 # [metric tonnes]
trunnion_width, 1800 # [mm]
trunnion_visual, res: EQ 180 trunnion.obj     # note, needs to be scaled and rotated to [m], origin at geometric center and beam in x-direction

# Optional settings
nonfixed_trunnion_cog, 1.1,2.2,3.3

# Optional setting for additional liftpoint on trunnion
trunnion_additional_liftpoint_name, AdditionalLiftpoint, # can be anything
trunnion_additional_liftpoint_position, 1, -.1, 2   # position relative to trunnion origin
trunnion_additional_liftpoint_diameter, 300 # [mm]
trunnion_additional_liftpoint_direction, 0,1,0.5 # direction of axis of liftpoint
#
*Slots  # data-table defining positions of the slots
# Name     , x [mm] , z [mm]
Lower 1    , 5250   , -500
Lower 2    , -5250   , -500
Upper 1    , 5250   , 500
Upper 2    , -5250   , 500
#
#
*Trunnions # data-table defining positions of the trunnions
# Name          , x [mm] , z [mm]
Trunnion1      ,  0      , -1000
Side Trunnion A,  5500       , 0
Side Trunnion B, -5500       , 0
#
*Liftpoints
# Name,         , x [mm]  , y [mm]  , z [mm] , diameter [mm], ux , uy , uz,
End A           , -6200   , 0       , -150      , 600        , -1 , 0  , 0
End B           ,  6200   , 0       , -150      , 600        ,  1 , 0  , 0
#
*Visuals
# Name , resource               , off-x, off-y, off-z, rot-x, rot-y, rot-z, scale-x, scale-y, scale-z,,,
Visual1, res: cylinder 1x1x1.obj,-6,0,0               ,0,90,0               ,1.2,1.2,12,
*Weights
#                                                                                                                                                    Note: interia is not used for statics
# 'Name',       'mass [mT]', 'Cog-x', 'Cog-y', 'Cog-z', 'footprint: elevation', 'footprint: aft', 'footprint: front', 'footprint: sb', 'footprint: ps', 'inertia: rxx', 'inertia: ryy', 'inertia: rzz'
EQ_main_steel,   17,           0       ,  0     ,  0     ,  0                    , -6              ,  6                ,   0           , 0              , 1             , 1             , 1
#