178 lines
4.5 KiB
ReStructuredText
178 lines
4.5 KiB
ReStructuredText
Stability
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=========
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Classes for stability analysis and GZ curve calculations.
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StabilityCalculator
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-------------------
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.. py:class:: StabilityCalculator(vessel, water_density=1025.0)
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Calculator for stability analysis (GZ curves).
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:param vessel: The vessel to calculate stability for
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:param water_density: Water density in kg/m³
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.. py:method:: gz_curve(displacement_mass, cog, heels)
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Calculates the GZ curve for a given loading condition.
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:param displacement_mass: Base vessel displacement (excluding dynamic tanks) in kg
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:param cog: Base center of gravity (LCG, TCG, VCG) excluding dynamic tanks
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:param heels: List of heel angles in degrees
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:returns: StabilityCurve object with corrected GZ values
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.. py:method:: kn_curve(displacements, heels, lcg=0.0, tcg=0.0)
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Calculates KN curves (Righting Lever from Keel) for multiple displacements.
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Returns one curve per displacement (cross-curves of stability).
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:param displacements: List of target displacements in kg
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:param heels: List of heel angles in degrees
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:param lcg: Longitudinal Center of Gravity (m)
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:param tcg: Transverse Center of Gravity (m)
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:returns: List of StabilityCurve objects
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.. py:method:: complete_stability(displacement_mass, cog, heels)
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Calculates complete stability analysis combining hydrostatics, GZ curve, and wind data.
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:param displacement_mass: Target displacement in kg
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:param cog: Center of gravity (LCG, TCG, VCG) tuple
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:param heels: List of heel angles for GZ curve in degrees
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:returns: CompleteStabilityResult with hydrostatics, GZ curve, and wind data
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CompleteStabilityResult
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-----------------------
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.. py:class:: CompleteStabilityResult
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Complete stability calculation result combining hydrostatics, GZ curve, and wind data.
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.. py:attribute:: hydrostatics
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:type: HydrostaticState
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Hydrostatic state at equilibrium (draft, trim, GM0, etc.).
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.. py:attribute:: gz_curve
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:type: StabilityCurve
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GZ stability curve for the loading condition.
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.. py:attribute:: wind_data
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:type: WindHeelingData or None
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Wind heeling data (if silhouettes are defined).
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.. py:attribute:: displacement
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:type: float
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Displacement mass in kg.
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.. py:attribute:: cog
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:type: tuple[float, float, float]
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Center of gravity (LCG, TCG, VCG).
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.. py:attribute:: gm0
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:type: float or None
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Initial transverse metacentric height (GM0) with free surface correction.
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.. py:attribute:: gm0_dry
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:type: float or None
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Initial transverse metacentric height without free surface correction.
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.. py:attribute:: max_gz
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:type: float or None
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Maximum GZ value on the curve.
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.. py:attribute:: heel_at_max_gz
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:type: float or None
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Heel angle at maximum GZ.
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.. py:method:: has_wind_data()
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Returns True if wind heeling data is available.
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:rtype: bool
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StabilityCurve
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--------------
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.. py:class:: StabilityCurve
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A complete GZ stability curve.
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.. py:method:: heels()
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Returns the heel angles.
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:rtype: list[float]
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.. py:method:: values()
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Returns the GZ values.
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:rtype: list[float]
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.. py:method:: points()
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Returns the points as a list of tuples (heel, draft, trim, gz).
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:rtype: list[tuple[float, float, float, float]]
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.. py:method:: get_stability_points()
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Returns a list of StabilityPoint objects with detailed information.
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Each StabilityPoint has:
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- ``heel``: Heel angle in degrees
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- ``draft``: Draft at equilibrium (m)
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- ``trim``: Trim angle in degrees
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- ``gz``: GZ value (m) (alias value)
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- ``value``: GZ or KN value (m)
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- ``is_flooding``: True if any opening is submerged
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- ``flooded_openings``: List of flooded opening names
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:rtype: list[StabilityPoint]
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.. py:attribute:: displacement
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:type: float
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Displacement in kg.
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WindHeelingData
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---------------
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.. py:class:: WindHeelingData
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Wind heeling data from silhouette calculations.
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Used for wind heeling moment calculations per IMO 2008 IS Code (MSC.267).
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.. py:attribute:: emerged_area
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:type: float
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Total emerged lateral area above waterline (m²).
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.. py:attribute:: emerged_centroid
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:type: tuple[float, float]
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Centroid of emerged area (x, z) in meters.
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.. py:attribute:: wind_lever_arm
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:type: float
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Lever arm from waterline to centroid z coordinate (m).
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.. py:attribute:: waterline_z
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:type: float
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Waterline Z at which calculations were performed.
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