Anisopter

The affordable solution for the rapid sizing of anisogrid structures.

Please, request a FREE TRIAL code at info@anisopter.com to quickly optimize your favorite cylindrical shell.

TRY DEMO v1.60

Credit: Unknown (from Tokkoro)

Why Anisogrid?

Anisogrid structures are the game-changing technology to save weight, reduce costs, and improve performance in modern spacecrafts and launchers.
Although transition to anisogrid is driven by the 14,000 €/kg of sending payloads to Space, Earth markets will also obtain important savings.




Anisopter

ANISOPTER on Earth

provides important benefits for companies developing high-performance structures where weight and cost efficiency is critical, like towers for electricity transport or wind power generation.


Credit: Stephane_Corvaja (Arianespace) - Vega-VV06 LISA-Pathfinder

Current state of development

ANISOPTER service is being implemented by ezeQ Apps and validated with our collaborator entities.



Credit: ESA-Stephane Corvaja, 2015 (source)

Quick Start

Contact us at info@anisopter.com to get a FREE TRIAL code.

Please, scroll down to either test a predefined example or optimize your favorite shell.

Basic workflow:

  • 1. Optimize your shell.
  • 2. Customize optimal dimensions for manufacture.
  • 3. Online FEA asessment of the model.
  • 4. Visualize the FEA model and download it.
  • 5. Generate and download Latticestruct nodes.

Warning, Anisopter is yet an experimental tool (code and web interface are being developed). Please, check results thoroughly before practical application!


Credit: NASA HQ PHOTO, 2016 (source)

Anisogrid cylindrical shell optimization or contact us at info@anisopter.com to get a free trial code.

Please, select some example to display its technical info.


Anisogrid ribs type
  • Select at least one rib model to perform the optimization.
  • More than one model can be selected to compare with.
  • Including other non-anisogrid design concepts, like tubes or isogrids, is also possible!
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Material
  • Once you select the desired material on the drop-down list, all required material properties will be automaticaly loaded.
  • Alternatively, introduce your favorite properties, they will be stored in "Custom material" for further use.
  • If different materials should be considered for Helical and Hoop ribs, please, fill Hoop ribs accordingly.
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Strength [MPa] Stiffness [GPa] Density [kg/m3]
Helical Hoop Helical Hoop Helical Hoop

Geometry
  • Length of the cylinder [m].
  • Diameters [m] of the cylinder at Base (or tapered tube at Top). Leave this field empty to optimize diameter.
  • Shell thicknesses [mm]. Wall thicknesses of the shell at Base and Top (tapered).
  • Ribs width/thickness [mm]. Rectangular/circular ribs width or tubular ribs wall-thickness. Use a negative value (<0) in helical ribs to constrain their width/thickness to shell's (e.g. use -1 for same width/thickness as shell, -0.5 for half, and so on...). Use a negative value (<0) in hoop ribs to constrain their width/thickness to helical's (e.g. use -1 for same width/thickness as helical ribs, -0.5 for half, and so on...).
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LengthDiameters [m]Shell/Ribs thicknesses [mm]
[m]
Base
Top
Base
Top
Helical
Hoop

Loads
  • Axial compressive force [N]. Applied on top. Compressive forces are positive.
  • Transverse force (top) [N]. Applied on top.
  • Bending moment [N·m] applied on top. E.g. the bending moment caused by a transverse force or the torque of a wind power generator (both applied on top).
  • Gravity. Set a non-zero gravity acceleration to consider self-weight (along x-axis), e.g. type 9.8 on Earth. Leave this field empty or type 0 to neglect self-weight. Significant in towers.
  • Mass on top [kg]. Mass attached to the top end of the shell. In resonance frequency calculations, only considered for Clamped-Free shell boundary conditions (Cantilever beam). If empty, only self-mass will be considered in all frequency calculations. If gravity is set, the weight of this mass will be added to current axial compressive force.
  • Lateral wind. ONLY for anisogrids with circular cross-section ribs! You can select Eurocode (EN 1991-1-4:2005) or Hoerner's aerodynamics book 1965 (it is based on pure aerodinamic considerations). Eurocode model is safer.
  • Wind category from Table 4.1 in Eurocode EN 1991-1-4:2005: 0= Sea or coastal area exposed to the open sea, 1= Lakes or flat and horizontal area with negligible vegetation and without obstacles, 2= Area with low vegetation such as grass and isolated obstacles (e.g. trees or buildings) with separations of at least 20 obstacle heights(default), 3= Area with regular cover of vegetation or buildings or with isolated obstacles with separations of maximum 20 obstacle heights (such as villages, suburban terrain, permanent forest), 4= Area in which at least 15 % of the surface is covered with buildings and their average height exceeds 15 m.
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Factor of Safety
Axial compressive force [N]
Bending moment [N·m]
Transverse force
at Top [N]
or Equivalent
moment [N·m]

Gravity [m/s2]
Mass on top [kg]

Constraints
  • Shell boundary. Boundary conditions for Euler-buckling of the whole shell.
  • Ribs boundary. Boundary conditions for Euler-buckling of the ribs (local ribs buckling). In Variable boundary conditions, the ribs end-fixity constants depend on neighboring members thickness (ONLY available yet for Rectangular ribs).
  • Axial stiffness. Expresed as minimum axial stiffness [N/m] or as maximum axial displacement [m] allowed.
  • Axial min. frequency [Hz]. Minimum frequecy allowed in the axial direction.
  • Lateral min. frequency [Hz]. Minimum frequecy allowed in the lateral direction.
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Shell boundary
Helical Ribs boundary
Hoop ribs boundary
Lateral max. shift [m]
Axial min. frequency [Hz]
Lateral min. frequency [Hz]

Wind
  • Lateral wind. ONLY for anisogrids with circular cross-section ribs! You can select Eurocode (EN 1991-1-4:2005) or Hoerner's aerodynamics book 1965 (it is based on pure aerodinamic considerations). Eurocode model is safer.
  • Wind category from Table 4.1 in Eurocode EN 1991-1-4:2005: 0= Sea or coastal area exposed to the open sea, 1= Lakes or flat and horizontal area with negligible vegetation and without obstacles, 2= Area with low vegetation such as grass and isolated obstacles (e.g. trees or buildings) with separations of at least 20 obstacle heights(default), 3= Area with regular cover of vegetation or buildings or with isolated obstacles with separations of maximum 20 obstacle heights (such as villages, suburban terrain, permanent forest), 4= Area in which at least 15 % of the surface is covered with buildings and their average height exceeds 15 m.
  • Roughness glass 0.0015, polished metal 0.002, fine paint 0.006, spray paint 0.02 bright steel 0.05, cast iron 0.2, galvanised steel 0.2, smooth concrete 0.2, planed wood 0.5, rough concrete 1.0, rough sawn wood 2.0, rust 2.0, brickwork 3.0.
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Lateral wind Solid
Base velocity [m/s]
Category
Roughness [mm]
Wind safety factor

Advanced options
φ [º]  # Helical ribs  # Hoop ribs
Min
Max
  Min
Max
Step
  Min
Max
Step
Screen diameters [m]
Min
Max
Step

Adjust final geometry
  • Adjust final cylinder dimensions to fulfill manufacturing (or other) constraints.
  • Note that forces, boundary conditions, and other constraints will be taken from optimization form.
  • In Non-Linear buckling analysis, forces are scaled by 5 (for tubular shells) and 3 (for anisogrids) to ensure buckling. The obtained buckling factor must be re-scaled accordingly.
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Shell type Diameter [m]
LengthDiameters [mm]Ribs/FEs [#]
[m]
Base
Top
Helical
Hoop
Diameters/Thicknesses [mm]
Helical,
Hoop, or
End ribs
Wall Thicknesses [mm]
of Shell of Ribs
Base
Top
Helical,
Hoop, or
End ribs

Finite Element Analysis
  • Perform a fast Finite Element Analysis to validate the optimized geometry.
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Nodes/beam Modes Element Boundary conditions
[#]
[#]
type
Bottom
Top
Straight beams    Exact wind
Perturb [mm] by mode or random
ANSYS   Element Type

Node parameters
  • Customize the node to fabricate your anisogrid.
  • Introduce the 6 relative position vectors of the 6 neighboring nodes (wrt. node center at the origin 0,0,0) required to generate any custom node, e.g. for a conical shell. Such vectors must conform the following format example, including sign-convention, order, and units [m]:
        -1.744484, 0.784209, 3.27906
        1.744484, 0.784209, 3.27906
        -2.095155, -0.062386, -3.593557
        2.095155, -0.062386, -3.593557
        -3.532539, 1.463226, 0
        3.532539, 1.463226, 0
  • (Click this box again to collapse)
 Res.

Custom node
  Parts solid top, bot., core half
  Bars all , top , hoop , bot.
  Fastener Hoop-arms z-off
  Dovetail Hoop
  Flip holes Heli.
Hub and Arms [mm]
Helical Height
Helical diam./thick.
Hoop diam./thick.
Hoop Height
Extra Core Dist.
Extra Axial Thick.
Extra External Thick.
Extra Internal Thick.
Dovetail Diam.
Fastener [mm]
External thickness
External width
External height
Internal thickness
Internal width
Internal height
Holes diameter
Hole distance in arms
in fastener
Tolerances [mm]
Helical ribs (1)
Hoop ribs (1)
Retention element (2)
Between halves (3)
Fastener (4)
Rotation

European Union
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 868615