Reduce Bolt Core

The Reduce Bolt command is intended to prepare a volume identified as a bolt for analysis by simplifying its geometry, fitting to overlapping geometry, creating blocks and groups, etc. For the core option of the reduce command, a cylindrical geometry surrounding the bolt will be webcut from the surrounding geometry. The core geometry is often used to define a higher resolution hex mesh than the surrounding geometry to better capture potential failure conditions. The core option can also manage corresponding "insert" volumes surrounding the shaft of the bolt.

Figure 1. Example before and after of the Reduce Bolt Core command


 Reduce volume {<ids>} bolt core [insert volume {<ids>}]
[c1 <value>] [c2 <value>] [c3 <value>] [diameter <value>]
[adjust_hole] [simplify_hole] [remove_key] [merge] [webcut [{Head|Shank|BOTH}]]
[mesh] [mesh_size <value>] [increment_block_ids]
[bolt_block_id {<value>|Default}] [bolt_block_name {<string>|Default}]
[head_block_id {<value>|Default}] [head_block_name {<string>|Default}]
[shank_block_id {<value>|Default}] [shank_block_name {<string>|Default}]
[plug_block_id {<value>|Default}] [plug_block_name {<string>|Default}]
[insert_block_id {<value>|Default}] [insert_block_name {<string>|Default}]
[core_top_block_id {<value>|Default}] [core_top_block_name {<string>|Default}]
[core_bottom_block_id {<value>|Default}] [core_bottom_block_name {<string>|Default}]


The dimensions of the core geometry is defined relative to the bolt so that it surrounds the bolt volume. Two core volumes are normally generated when the cylindrical core geometry is subtracted from the top and bottom volumes as illustrated in figure 1. In addition to generating the core volumes, the bolt can be automatically webcut into three parts: head, shank and plug. If an insert volume is present, it can be automatically modified to remove overlap and merged to the shank and hole surfaces. In addition the diameter of the bolt shank can be altered, the hole fit to the shank diameter and the the allen key cavity optionally removed. The resulting volumes can in turn be hex meshed and assigned to blocks.

An example of the reduce bolt core operation is illustrated in figures 2 and 3. In this example, an "insert" volume is present that is overlapping the hole geometry. The resulting geometry from the operation is shown in figure 3.

Figure 2. Bolt and insert geometry prior to reduce bolt core operation showing nearby volumes.

Figure 3. Bolt, insert and core volumes after the reduce operation

The reduce bolt core operation also provides the option to assign the resulting volumes to blocks and mesh the volumes at a specified size. Figure 4 illustrates the resulting default blocks and mesh denerated from the example shown in figure 3.

Figure 4. Example blocks and mesh automatically generated from the Reduce Bolt Core command

The following outlines the options for the reduce bolt fit_volume command.

volume ids: Specify the ids of the volumes to be reduced. The Geometry Power Tool classification diagnosic can be used for identifying volumes as "bolts".

Optional Arguments

insert volume {<ids>}If an insert volume is present, specify its volume ID if it to be included in the operation. When multiple bolts and inserts are used, the command will automatically pair a corresponding insert for each bolt. If one or more insert volumes are specified, one insert volume must be supplied for each bolt. If an insert volume does not overlap the bounding box of its corresponding bolt, it will be ignored.

c1 <value>, c2 <value>, c3 <value>: Dimensions relative to the bolt defining the size of the core geometry as illustrated in Figure 1.

  1. c1 <value>: Distance from the top of the bolt head to the top of the core geometry.
  2. c2 <value>: Distance from the bottom of the bolt shaft to the bottom of the core geometry.
  3. c3 <value>: Radius of core relative to the center line of the bolt.

diameter <value>: Use the diameter option to alter the diameter of the bolt shaft. If no value is specified for diameter, the existing diameter of the bolt will be used.

adjust_hole: Modify the diameter of the hole to match the diameter of the shaft. This option should only be used if an insert volume is not present.

simplify_hole: Optionally remove any conical shaped surfaces from the bottom of the hole geometry.

remove_key: If an allen key cavity is present in the bolt head (see figure 1), this option will attempt to remove it. If not used, the allen key cavity will be preserved in the final geometry and resulting mesh.

merge: When the merge option is used the generated volumes will be automatically merged. If a contiguous mesh is desired, this option should be used.

webcut [{Head|Shank|BOTH}]: When using core option with webcut, the bolt can be cut into up to 3 different volumes as shown in figure 1. Using the optional Head or Shank options a single webcut can be executed separating just the head from the shank or just the shank from the plug respectively. If no arguments are used to the webcut option, or the both option is used, both webcuts will be performed resulting in three volumes. The resulting volumes will be merged together. The location of the webcut on the shank will be where the bolt exits the volume to which it is fastened.

mesh: Automatically attempt hex meshing of all resulting volumes.

mesh_size <value>: When the mesh option is used, this value will specify a target mesh size for the hex mesh. If a mesh size is not supplied, the mesh size specified on the volume will be used. If neither are present, a default size will be computed and used for meshing.

Block IDs and/or names can be specified for the resulting volumes. Blocks may be defined by either a block_name or block_id. If the block does not yet exist, a new one will be created. The Default option will automatically select an id or name. If the webcut option is used, the following blocks may be specified:

Otherwise a single block containing the simplified bolt can be specified:

If the insert volume is present, the following block may be specified: The top and bottom core volumes may also be assigned to blocks using the following options:

increment_block_ids: When assigning the volumes to blocks, the block ID can be automatically generated by incrementing from a specified block_id. For example, if head_block_id is defined as 100, and the increment_block_ids option is used, each new head volume generated will be assigned to a new unique block id starting with 100, followed by 101, 102, 103, etc.

preview: optional argument to display a preview of the reduce bolt core operation without execution of the reduction. This option will display the reduced bolt geometry in blue, the core geometry in red and with the surrounding volumes displayed in wireframe.