# RCAIDE/Library/Plots/Mass_Properties/plot_load_diagram.py
#
#
# Created: Aug 2025, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
from RCAIDE.Framework.Core import Units
from RCAIDE.Library.Plots.Common import set_axes, plot_style
import matplotlib.pyplot as plt
from scipy.spatial import ConvexHull
from shapely.geometry import Polygon
import matplotlib.cm as cm
from scipy.interpolate import griddata
import matplotlib.tri as tri
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# PLOTS
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def plot_load_diagram(results,
save_figure = False,
show_legend = True,
save_filename = "Aircraft_Loading_Trim_Dragram",
file_type = ".png",
static_margin_lower_limit = -0.1,
static_margin_upper_limit = 1.0,
static_margin_resolution = 12,
x_axis_lower_limit = None,
x_axis_upper_limit = None,
y_axis_lower_limit = None,
y_axis_upper_limit = None,
show_component_vectors = False,
width = 11,
height = 7):
"""
Creates a comprehensive aircraft loading diagram showing mass and center of gravity relationships.
Parameters
----------
results : RCAIDE.Framework.Core.Data
Results from load and trim diagram analysis containing:
- loading_mass : numpy.ndarray
Aircraft mass for loading diagram [kg]
- loading_LEMAC_location : numpy.ndarray
LEMAC location as percentage of reference chord [%]
- trim_results.LEMAC_location : numpy.ndarray
LEMAC location for trim diagram [%]
- trim_results.mass : numpy.ndarray
Aircraft mass for trim diagram [kg]
- trim_results.static_margin : numpy.ndarray
Static margin values [unitless]
- MTOW : float
Maximum takeoff weight [kg]
- MLW : float
Maximum landing weight [kg]
Returns
-------
None
Creates and displays a matplotlib figure with the loading diagram
Notes
-----
This function generates a comprehensive aircraft loading diagram that visualizes
the relationship between aircraft mass, loading, and center of gravity position. The diagram
includes fuel loading curves, payload loading curves, weight limits, and stability
contours to provide a complete view of the aircraft's loading envelope.
**Major Assumptions**
* Convex hull calculation is valid for the data points
**Definitions**
'Loading Diagram'
Plot showing aircraft mass versus center of gravity position for different loading conditions.
'Convex Hull'
Smallest convex polygon that contains all the data points.
'Static Margin'
Distance between center of gravity and neutral point as percentage of reference chord.
'LEMAC'
Leading Edge Mean Aerodynamic Chord reference point for center of gravity calculations.
See Also
--------
matplotlib.pyplot
scipy.spatial.ConvexHull
shapely.geometry.Polygon
"""
# get plotting style
ps = plot_style()
parameters = {'axes.labelsize': ps.axis_font_size,
'xtick.labelsize': ps.axis_font_size,
'ytick.labelsize': ps.axis_font_size,
'axes.titlesize': ps.title_font_size}
plt.rcParams.update(parameters)
fig = plt.figure(save_filename)
fig.set_size_inches(width,height)
axis = fig.add_subplot(1,1,1)
# ------------------------------------------------------------------------
# Stability Contours
# ------------------------------------------------------------------------
CG_LEMAC = results.trim_results.CG_percent_of_LEMAC_location*100
SM = results.trim_results.static_margin*100
SM_levels = np.linspace(static_margin_lower_limit*100, static_margin_upper_limit*100, static_margin_resolution)
# extend contour grid vertically so it covers the full hull range
mass_grid = results.trim_results.mass
mass_min = mass_grid.min()
mass_max = mass_grid.max()
pad_lo = mass_min - 0.1 * (mass_max - mass_min)
pad_hi = mass_max + 0.1 * (mass_max - mass_min)
CG_LEMAC = np.vstack([CG_LEMAC[0:1, :], CG_LEMAC, CG_LEMAC[-1:, :]])
SM = np.vstack([SM[0:1, :], SM, SM[-1:, :]])
mass_grid = np.vstack([np.full_like(mass_grid[0:1, :], pad_lo), mass_grid, np.full_like(mass_grid[-1:, :], pad_hi)])
CS = axis.contourf(CG_LEMAC, mass_grid, SM, levels = SM_levels, cmap='coolwarm_r', extend='both', alpha = 0.5)
CS2 = axis.contour(CG_LEMAC, mass_grid, SM, levels = SM_levels, colors='black', extend='both')
cbar = fig.colorbar(CS, ax=axis)
axis.clabel(CS2, fontsize=10)
cbar.ax.set_ylabel('Static Margin', rotation = 90)
# ------------------------------------------------------------------------
# load diamonds
# ------------------------------------------------------------------------
# cumulative load vector diamond
points = np.hstack(( 100*np.atleast_2d(results.loading_results.CG_percent_of_LEMAC_location.flatten()).T, np.atleast_2d(results.loading_results.mass.flatten()).T ))
hull = ConvexHull(points)
hull_points = points[hull.vertices]
polygon = Polygon(hull_points)
x_hull, y_hull = polygon.exterior.xy
# fuel vector diamond
points = np.hstack(( 100*np.atleast_2d(results.loading_results.CG_percent_of_LEMAC_location[:,0,0,:].flatten()).T, np.atleast_2d(results.loading_results.mass[:,0,0,:].flatten()).T ))
hull = ConvexHull(points)
hull_points = points[hull.vertices]
polygon = Polygon(hull_points)
x_hull_f, y_hull_f = polygon.exterior.xy
# passenger vector diamond
points = np.hstack(( 100*np.atleast_2d(results.loading_results.CG_percent_of_LEMAC_location[:,:,0,0].flatten()).T, np.atleast_2d(results.loading_results.mass[:,:,0,0].flatten()).T ))
hull = ConvexHull(points)
hull_points = points[hull.vertices]
polygon = Polygon(hull_points)
x_hull_p, y_hull_p = polygon.exterior.xy
# cargo vector diamond
points = np.hstack(( 100*np.atleast_2d(results.loading_results.CG_percent_of_LEMAC_location[:,0,:,0].flatten()).T, np.atleast_2d(results.loading_results.mass[:,0,:,0].flatten()).T ))
hull = ConvexHull(points)
hull_points = points[hull.vertices]
polygon = Polygon(hull_points)
x_hull_c, y_hull_c = polygon.exterior.xy
# ------------------------------------------------------------------------
# PLot Bounds
# ------------------------------------------------------------------------
x_bound = max(x_hull) - min(x_hull)
if x_axis_lower_limit == None:
x_axis_lower_limit = min(x_hull) - x_bound / 2
if x_axis_upper_limit == None:
x_axis_upper_limit = max(x_hull) + x_bound / 2
if y_axis_lower_limit == None:
y_axis_lower_limit = min(y_hull)
if y_axis_upper_limit == None:
y_axis_upper_limit = max(y_hull)
# ------------------------------------------------------------------------
# Maximum Takeoff Weight line
# ------------------------------------------------------------------------
x_pts_MTOW = np.linspace(x_axis_lower_limit, x_axis_upper_limit)
y_pts_MTOW = np.ones_like(x_pts_MTOW) * results.MTOW
axis.plot(x_pts_MTOW, y_pts_MTOW, 'g-', label = 'MTOW')
# ------------------------------------------------------------------------
# Maximum Landing Weight line
# ------------------------------------------------------------------------
x_pts_MLW = np.linspace(x_axis_lower_limit, x_axis_upper_limit)
y_pts_MLW = np.ones_like(x_pts_MLW) * results.MLW
axis.plot(x_pts_MLW, y_pts_MLW, 'g-x', label = 'MLW')
# ------------------------------------------------------------------------
# Loading -Trim Bounds
# ------------------------------------------------------------------------
axis.fill(x_hull, y_hull, color='grey', alpha=0.3, edgecolor='black', linewidth=2)
axis.plot(x_hull, y_hull, 'k-')
if show_component_vectors:
axis.fill(x_hull_f, y_hull_f, color = 'goldenrod' , alpha=0.3 , edgecolor='goldenrod', linewidth=1)
axis.plot(x_hull_f, y_hull_f, color = 'goldenrod' , linestyle = '-',label = "Fuel Loading")
axis.fill(x_hull_p, y_hull_p, color = 'darkred' , alpha=0.3 , edgecolor='darkred', linewidth=1)
axis.plot(x_hull_p, y_hull_p, color = 'darkred' , linestyle = '-',label = "Pax. Loading")
axis.fill(x_hull_c, y_hull_c, color = 'darksalmon' , alpha=0.3 , edgecolor='darksalmon', linewidth=1)
axis.plot(x_hull_c, y_hull_c, color = 'darksalmon' , linestyle = '-',label = "Cargo Loading")
# ------------------------------------------------------------------------
# Axis Items
# ------------------------------------------------------------------------
axis.set_xlim(x_axis_lower_limit, x_axis_upper_limit)
axis.set_ylim(y_axis_lower_limit, y_axis_upper_limit)
axis.legend(loc='upper right')
axis.set_xlabel(r'$X_{CG}$/LEMAC (%)')
axis.set_ylabel('Mass (kg)')
plt.grid(False)
fig.tight_layout()
if save_figure:
plt.savefig(save_filename + file_type)
return
