czarified / cslm Goto Github PK

Additional engines should be added, matching the layout of the 2019 Starship Update. CONM2 elements should be used, offset from the thrust plate.

Current engine element has too low of a mass value!

SL Raptor mass is currently approximated at 2050 kg, based on a TWR of 100.

Vac Raptors will weigh slightly more.

Mass elements should be MPC'd to the thrust structure with an RBE3 or CBUSH. RBE3's are easier, so they should do for starters.

As expected, and seen in the engine bay pics for Starship MkI, the surrounding skins are heavily reinforced in the longitudinal direction with stringers. Since the scale of CSLM is limited, this effect cannot be fully captured by splitting elements and using bars to represent all the stringers. Instead, it would be advantageous to develop an orthotropic PSHELL card based on the geometry and constituent stiffness's.

For reference materials see "Mechanics of Composites" by Jones, chapter 2.

It would also be advantageous to link the reference images or save copies locally to the project.

Fin and Tail geometry will need to be updated to match what is presented by Elon on the 9/28/19 Starship Update.

After OML geometry is modified to match. Internal structure should be created to match what can be seen from the prototype builds, as best as feasible. Spar(s) and ribs should be added, and mesh should equivalence with existing skin and thrust plate nodes.

Thrust plate needs to be reworked to be more accurate to reality. Multiple images of the prototype thrust plate can be found from NSF and r/spacex. Briefly, base plate needs a more organized and refined mesh.

The prototpye has a secondary plate, but it's unclear at this time what the point of this secondary plate is.

• http://openvsp.org/wiki/doku.php?id=workshop2019
  • «Git Version control of VSP models and libraries» - http://openvsp.org/wiki/lib/exe/fetch.php?media=workshop19:vsp-ws19_git_version_control.pdf

Skin thicknesses should be generally reduced, whereas bulkheads and domes should remain at 5mm. Suggested starting point is reducing all skin properties to 2.5mm (half of current value).

Results and rationale for specifics should be posted under this issue in the comments.

LC100 solves, but peak stresses are more than 100 GPA and deformations show the tank sections immediately crumpling under the pressure.

1. Import the exec deck into a new DB to verify inputs were created correctly.

2. Scale deformations to find problem areas if loads seem to be correct.

3. Verify element orientations, properties, and continuity.

Rework of all pressure cards to include hydrostatic pressures from the mass of the propellants.

Creation of LC110, "Launch Config, Full Propellant, 1G, No Crosswind, Liftoff!, SH Thrust"

Same propellant pressures and accelerations as LC100, but instead of SPC around the base, thrust from SH will be applied.

In order to change weight conditions, certain mass elements will need to exist and be attached to the airframe. These mass elements will be located at "golden grids" and RBE3'd to the local structure.

• Create new nodes along the centerline of the structure. At least 2 per tank.

• Optionally, create new nodes along the centerline in the payload bay, to represent payload/crew masses.

• Document these new nodes in this thread (screenshot, with nodes labeled).

• Attach these nodes to local structure with new RBE3's. Use a consistent numbering scheme (Starting at id 100?)

• Create 0d mass elements at each golden grid. Use a consistent numbering scheme.

• Include all mass elements, golden grids, and RBE3's in a new group.

• Record all id's in a table in this thread.

To get more realistic results and better match realistic load paths, structural rings should be added around the circumference of the pressure vessels.

Rings should be created at various stations, for starters, and possibly expanded to every station, in the future.

Rings constructed of CBEAM elements, initially with a T-section (presumably to join the OML skin rings together on the flange, with a free web for radial strength when under pressure).