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authorblendoit <blendoit@gmail.com>2019-11-01 18:12:34 -0700
committerblendoit <blendoit@gmail.com>2019-11-01 18:12:34 -0700
commit8b6f11119790c8c930734894a37d2a4aaa42462d (patch)
tree9d6b9013ad4522f9a5598f30b4d3a0fcd26810ac /aircraftstudio/creator/wing.py
parent5ab73817371c1b4fedbd98838d3cf28984d73004 (diff)
Start work on optimized multiprocessing random a/c gen. & eval.HEADmaster
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+"""
+The wing.py module contains class definitions for and various components
+we add to an airfoil (spars, stringers, and ribs).
+
+Classes:
+ Airfoil: instantiated with class method to provide coordinates to heirs.
+ Spar: inherits from Airfoil.
+ Stringer: also inherits from Airfoil.
+
+Functions:
+ plot_geom(airfoil): generates a 2D plot of the airfoil & any components.
+"""
+
+import logging
+import numpy as np
+from math import sin, cos, atan
+import bisect as bi
+import matplotlib.pyplot as plt
+
+from aircraftstudio.creator import base
+import resources.materials as mt
+
+
+class Airfoil(base.Component):
+ """This class represents a single NACA airfoil.
+
+ The coordinates are saved as two np.arrays
+ for the x- and z-coordinates. The coordinates start at
+ the leading edge, travel over the airfoil's upper edge,
+ then loop back to the leading edge via the lower edge.
+
+ This method was chosen for easier future exports
+ to 3D CAD packages like SolidWorks, which can import such
+ geometry as coordinates written in a CSV file.
+ """
+ def __init__(self,
+ parent,
+ name,
+ chord=68,
+ semi_span=150,
+ material=mt.aluminium):
+ super().__init__(parent, name)
+ parent.wing = self
+ if chord > 20:
+ self.chord = chord
+ else:
+ self.chord = 20
+ logging.debug('Chord too small, using minimum value of 20.')
+ parent
+ self.semi_span = semi_span
+ self.material = material
+ self.spars = []
+ self.stringers = []
+
+ def add_naca(self, naca_num=2412):
+ """Generate surface geometry for a NACA airfoil.
+
+ The nested functions perform the required steps to generate geometry,
+ and can be called to solve the geometry y-coordinate for any 'x' input.
+ Equation coefficients were retrieved from Wikipedia.org.
+
+ Parameters:
+ naca_num: 4-digit NACA wing
+
+ Return:
+ None
+ """
+ self.naca_num = naca_num
+ # Variables extracted from naca_num argument passed to the function
+ m = int(str(naca_num)[0]) / 100
+ p = int(str(naca_num)[1]) / 10
+ t = int(str(naca_num)[2:]) / 100
+ # x-coordinate of maximum camber
+ p_c = p * self.chord
+
+ def get_camber(x):
+ """
+ Returns camber z-coordinate from 1 'x' along the airfoil chord.
+ """
+ z_c = float()
+ if 0 <= x < p_c:
+ z_c = (m / (p**2)) * (2 * p * (x / self.chord) -
+ (x / self.chord)**2)
+ elif p_c <= x <= self.chord:
+ z_c = (m /
+ ((1 - p)**2)) * ((1 - 2 * p) + 2 * p *
+ (x / self.chord) - (x / self.chord)**2)
+ return (z_c * self.chord)
+
+ def get_thickness(x):
+ """Return thickness from 1 'x' along the airfoil chord."""
+ x = 0 if x < 0 else x
+ z_t = 5 * t * self.chord * (+0.2969 *
+ (x / self.chord)**0.5 - 0.1260 *
+ (x / self.chord)**1 - 0.3516 *
+ (x / self.chord)**2 + 0.2843 *
+ (x / self.chord)**3 - 0.1015 *
+ (x / self.chord)**4)
+ return z_t
+
+ def get_theta(x):
+ dz_c = float()
+ if 0 <= x < p_c:
+ dz_c = ((2 * m) / p**2) * (p - x / self.chord)
+ elif p_c <= x <= self.chord:
+ dz_c = (2 * m) / ((1 - p)**2) * (p - x / self.chord)
+
+ theta = atan(dz_c)
+ return theta
+
+ def get_coord_u(x):
+ x = x - get_thickness(x) * sin(get_theta(x))
+ z = get_camber(x) + get_thickness(x) * cos(get_theta(x))
+ return (x, z)
+
+ def get_coord_l(x):
+ x = x + get_thickness(x) * sin(get_theta(x))
+ z = get_camber(x) - get_thickness(x) * cos(get_theta(x))
+ return (x, z)
+
+ # Densify x-coordinates 10 times for first 1/4 chord length
+ x_chord_25_percent = round(self.chord / 4)
+ x_chord = [i / 10 for i in range(x_chord_25_percent * 10)]
+ x_chord.extend(i for i in range(x_chord_25_percent, self.chord + 1))
+ # Generate our airfoil skin geometry from previous sub-functions
+ self.x_c = np.array([])
+ self.z_c = np.array([])
+ # Upper surface and camber line
+ for x in x_chord:
+ self.x_c = np.append(self.x_c, x)
+ self.z_c = np.append(self.z_c, get_camber(x))
+ self.x = np.append(self.x, get_coord_u(x)[0])
+ self.z = np.append(self.z, get_coord_u(x)[1])
+ # Lower surface
+ for x in x_chord[::-1]:
+ self.x = np.append(self.x, get_coord_l(x)[0])
+ self.z = np.append(self.z, get_coord_l(x)[1])
+ return None
+
+
+class Spar(base.Component):
+ """Contains a single spar's data."""
+ def __init__(self, parent, name, loc_percent=0.30, material=mt.aluminium):
+ """Set spar location as percent of chord length."""
+ super().__init__(parent, name)
+ parent.spars.append(self)
+ self.material = material
+ self.cap_area = float()
+ # bi.bisect_left: returns index of first value in parent.x > loc
+ # This ensures that spar geom intersects with airfoil geom.
+ loc = loc_percent * parent.chord
+ # Spar upper coordinates
+ spar_u = bi.bisect_left(parent.x, loc) - 1
+ self.x = np.append(self.x, parent.x[spar_u])
+ self.z = np.append(self.z, parent.z[spar_u])
+ # Spar lower coordinates
+ spar_l = bi.bisect_left(parent.x[::-1], loc)
+ self.x = np.append(self.x, parent.x[-spar_l])
+ self.z = np.append(self.z, parent.z[-spar_l])
+ return None
+
+ def set_cap_area(self, cap_area):
+ self.cap_area = cap_area
+ return None
+
+ def set_mass(self, mass):
+ self.mass = mass
+ return None
+
+
+class Stringer(base.Component):
+ """Contains the coordinates of all stringers."""
+ def __init__(self,
+ parent,
+ name,
+ den_u_1=4,
+ den_u_2=4,
+ den_l_1=4,
+ den_l_2=4):
+ """Add equally distributed stringers to four airfoil locations
+ (upper nose, lower nose, upper surface, lower surface).
+
+ den_u_1: upper nose number of stringers
+ den_u_2: upper surface number of stringers
+ den_l_1: lower nose number of stringers
+ den_l_2: lower surface number of stringers
+ """
+ super().__init__(parent, name)
+ parent.stringers = self
+ self.x_start = []
+ self.x_end = []
+ self.z_start = []
+ self.z_end = []
+ self.diameter = float()
+ self.area = float()
+
+ # Find distance between leading edge and first upper stringer
+ # interval = self.parent.spars[0].x[0] / (den_u_1 + 1)
+ interval = 2
+ # initialise first self.stringer_x at first interval
+ x = interval
+ # Add upper stringers from leading edge until first spar.
+ for _ in range(0, den_u_1):
+ # Index of the first value of airfoil.x > x
+ i = bi.bisect_left(self.parent.x, x)
+ self.x = np.append(self.x, self.parent.x[i])
+ self.z = np.append(self.z, self.parent.z[i])
+ x += interval
+ # Add upper stringers from first spar until last spar
+ interval = (self.parent.spars[-1].x[0] -
+ self.parent.spars[0].x[0]) / (den_u_2 + 1)
+ x = interval + self.parent.spars[0].x[0]
+ for _ in range(0, den_u_2):
+ i = bi.bisect_left(self.parent.x, x)
+ self.x = np.append(self.x, self.parent.x[i])
+ self.z = np.append(self.z, self.parent.z[i])
+ x += interval
+
+ # Find distance between leading edge and first lower stringer
+ interval = self.parent.spars[0].x[1] / (den_l_1 + 1)
+ x = interval
+ # Add lower stringers from leading edge until first spar.
+ for _ in range(0, den_l_1):
+ i = bi.bisect_left(self.parent.x[::-1], x)
+ self.x = np.append(self.x, self.parent.x[-i])
+ self.z = np.append(self.z, self.parent.z[-i])
+ x += interval
+ # Add lower stringers from first spar until last spar
+ interval = (self.parent.spars[-1].x[1] -
+ self.parent.spars[0].x[1]) / (den_l_2 + 1)
+ x = interval + self.parent.spars[0].x[1]
+ for _ in range(0, den_l_2):
+ i = bi.bisect_left(self.parent.x[::-1], x)
+ self.x = np.append(self.x, self.parent.x[-i])
+ self.z = np.append(self.z, self.parent.z[-i])
+ x += interval
+ return None
+
+ def add_area(self, area):
+ self.area = area
+ return None
+
+ def add_mass(self, mass):
+ self.mass = len(self.x) * mass + len(self.x) * mass
+ return None
+
+ def add_webs(self, thickness):
+ """Add webs to stringers."""
+ for _ in range(len(self.x) // 2):
+ self.x_start.append(self.x[_])
+ self.x_end.append(self.x[_ + 1])
+ self.z_start.append(self.z[_])
+ self.z_end.append(self.z[_ + 1])
+ self.thickness = thickness
+ return None
+
+ def info_print(self, round=2):
+ super().info_print(round)
+ print('Stringer Area:\n', np.around(self.area, round))
+ return None
+
+
+def plot_geom(airfoil):
+ """This function plots the airfoil's + sub-components' geometry."""
+ fig, ax = plt.subplots()
+
+ # Plot chord
+ x = [0, airfoil.chord]
+ y = [0, 0]
+ ax.plot(x, y, linewidth='1')
+ # Plot quarter chord
+ ax.plot(airfoil.chord / 4,
+ 0,
+ '.',
+ color='g',
+ markersize=24,
+ label='Quarter-chord')
+ # Plot mean camber line
+ ax.plot(airfoil.x_c,
+ airfoil.z_c,
+ '-.',
+ color='r',
+ linewidth='2',
+ label='Mean camber line')
+ # Plot airfoil surfaces
+ ax.plot(airfoil.x, airfoil.z, color='b', linewidth='1')
+
+ try: # Plot spars
+ for spar in airfoil.spars:
+ x = (spar.x)
+ y = (spar.z)
+ ax.plot(x, y, '-', color='y', linewidth='4')
+ except AttributeError:
+ print('No spars to plot.')
+ try: # Plot stringers
+ for i in range(len(airfoil.stringers.x)):
+ x = airfoil.stringers.x[i]
+ y = airfoil.stringers.z[i]
+ ax.plot(x, y, '.', color='y', markersize=12)
+ except AttributeError:
+ print('No stringers to plot.')
+
+ ax.set(title='NACA ' + str(airfoil.naca_num) + ' airfoil',
+ xlabel='X axis',
+ ylabel='Z axis')
+
+ plt.grid(axis='both', linestyle=':', linewidth=1)
+ plt.gca().set_aspect('equal', adjustable='box')
+ plt.gca().legend(bbox_to_anchor=(1, 1),
+ bbox_transform=plt.gcf().transFigure)
+ plt.show()
+ return fig, ax
Copyright 2019--2024 Marius PETER