Input File Format

B3P uses YAML files to define wind turbine blade models, including geometry, materials, laminates, and loads. This guide describes the structure and key sections of a B3P input file.

File Structure

A B3P input file is a YAML document with the following top-level sections:

• general: General settings (e.g., working directory, prefix).
• aero: Aerodynamic properties and airfoil data.
• mesh: Blade geometry and meshing parameters.
• materials: Material properties or path to material database.
• laminates: Composite laminate definitions.
• loads: Load cases for structural analysis.

Example Input File

Below is a simplified example of a B3P input file:

general:
  prefix: my_blade
  workdir: ./output_portable

aero:
  airfoils:
    0.18: path/to/airfoil_18.dat
    0.21: path/to/airfoil_21.dat
  bem:
    rated_power: 10e6  # 10 MW
    B: 3  # Number of blades
    rho: 1.225  # Air density
    max_tipspeed: 95.0
    uinf: [3, 5, 7, 9, 10, 11, 12, 13, 16, 20]

mesh:
  radii: [0.1, 5, 10, 20, 50, 100]
  n_web_points: 10
  n_chordwise_points: 120
  webs:
    web1:
      origin: [0, 0.1, 0]
      z_start: 0.1
      z_follow_blade: 50
      z_end: 100
      orientation: [0, 1, 0]
  bondline:
    material: adhesive
    width: [[0, 0], [0.5, 0.5], [1, 0.1]]

materials: path/to/materials.yml

laminates:
  slabs:
    shell:
      material: carbon_ud
      ply_thickness: 0.001
      slab: [[0, 0.01], [0.5, 0.02], [1, 0.015]]
      cover:
        chord: [0.1, 0.9, 0]
  datums:
    chord:
      xy: [[0, 0], [0.5, 0.5], [1, 1]]
      scalex: 1.0
      scaley: 1.0

loads:
  forward_flap:
    z: [0, 50, 100]
    mx: [0, 1e6, 2e6]
    my: [0, 0, 0]
    apply:
      radius: [0, 100]

Section Details

general

• prefix: Prefix for output files (e.g., my_blade).
• workdir: Working directory for output (e.g., ./output_portable).

aero

• airfoils: Dictionary mapping thickness ratios to airfoil data files (XFOIL format).
• bem: Blade element momentum (BEM) parameters for CCBlade:
• rated_power: Turbine power rating (W).
• B: Number of blades.
• rho: Air density (kg/m³).
• max_tipspeed: Maximum tip speed (m/s).
• uinf: Array of wind speeds (m/s).

mesh

• radii: List of radial positions for meshing (m).
• n_web_points: Number of points for web meshing.
• n_chordwise_points: Number of chordwise points for shell meshing.
• webs: Dictionary of web definitions:
• origin: Web origin point [x, y, z].
• z_start: Start of web along blade span (m).
• z_follow_blade: Point where web follows blade geometry (m).
• z_end: End of web (m).
• orientation: Normal vector of web plane [x, y, z].
• bondline: Bondline configuration:
• material: Material name for bondline.
• width: List of [radius, width] pairs for bondline width variation.
• coordinates (optional): Additional datum points for meshing.

materials

• Path to a YAML file defining material properties or a dictionary of materials.
• Example material file (materials.yml):

  carbon_ud:
    name: Carbon UD
    e11: 135e9
    e22: 10e9
    e33: 10e9
    g12: 5e9
    g13: 5e9
    g23: 4e9
    nu12: 0.3
    nu13: 0.3
    nu23: 0.4
    rho: 1600
  adhesive:
    name: Adhesive
    E: 3e9
    nu: 0.35
    rho: 1200
  

laminates

• slabs: Dictionary of laminate slabs:
• material: Material name (must match materials).
• ply_thickness: Thickness of each ply (m).
• slab: List of [radius, thickness] pairs for thickness distribution.
• cover: Chordwise coverage [start, end, increment].
• draping: Either plies (individual plies) or blocks (core blocks).
• datums: Coordinate systems for coverage calculations.

loads

• Dictionary of load cases (e.g., forward_flap):
• z: Radial positions for load application (m).
• mx, my: Moments about x and y axes (N·m).
• apply: Conditions for load application (e.g., radius: [min, max]).

Notes

• File paths (e.g., airfoils, materials) are relative to the YAML file unless absolute.
• Use b3p yml_portable blade.yml to create a portable version with embedded linked files.
• Validate YAML syntax using a linter or the B3P CLI.

For a complete example, see Blade Test Example.