diff options
Diffstat (limited to 'evaluator')
| -rw-r--r-- | evaluator/evaluator.py | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/evaluator/evaluator.py b/evaluator/evaluator.py new file mode 100644 index 0000000..6c7f901 --- /dev/null +++ b/evaluator/evaluator.py @@ -0,0 +1,284 @@ +""" +The evaluator.py module contains a single Evaluator class, +which knows all the attributes of a specified Aircraft instance, +and contains functions to analyse the airfoil's geometrical +& structural properties. +""" + +import sys +import os.path +import numpy as np +from math import sqrt +import matplotlib.pyplot as plt + + +class Evaluator: + """Performs structural evaluations for the airfoil passed as argument.""" + def __init__(self, airfoil): + # Evaluator knows all geometrical info from evaluated airfoil + self.airfoil = airfoil + self.spar = airfoil.spar + self.stringer = airfoil.stringer + # Global dimensions + self.chord = airfoil.chord + self.semi_span = airfoil.semi_span + # Mass & spanwise distribution + self.mass_total = float(airfoil.mass + airfoil.spar.mass + + airfoil.stringer.mass) + self.mass_dist = [] + # Lift + self.lift_rectangular = [] + self.lift_elliptical = [] + self.lift_total = [] + # Drag + self.drag = [] + # centroid + self.centroid = [] + # Inertia terms: + self.I_ = {'x': 0, 'z': 0, 'xz': 0} + + def __str__(self): + return type(self).__name__ + + def info_print(self, round): + """Print all the component's evaluated data to the terminal.""" + name = ' EVALUATOR DATA FOR {} '.format(str(self).upper()) + num_of_dashes = len(name) + print(num_of_dashes * '-') + print(name) + for k, v in self.__dict__.items(): + if type(v) != list: + print('{}:\n'.format(k), v) + print(num_of_dashes * '-') + for k, v in self.__dict__.items(): + if type(v) == list: + print('{}:\n'.format(k), np.around(v, round)) + return None + + def info_save(self, save_path, number): + """Save all the object's coordinates (must be full path).""" + file_name = 'airfoil_{}_eval.txt'.format(number) + full_path = os.path.join(save_path, file_name) + try: + with open(full_path, 'w') as sys.stdout: + self.info_print(6) + # This line required to reset behavior of sys.stdout + sys.stdout = sys.__stdout__ + print('Successfully wrote to file {}'.format(full_path)) + except IOError: + print( + 'Unable to write {} to specified directory.\n'.format( + file_name), 'Was the full path passed to the function?') + return None + + # All these functions take integer arguments and return lists. + + def get_lift_rectangular(self, lift): + L_prime = [lift / (self.semi_span * 2) for x in range(self.semi_span)] + return L_prime + + def get_lift_elliptical(self, L_0): + L_prime = [ + L_0 / (self.semi_span * 2) * sqrt(1 - (y / self.semi_span)**2) + for y in range(self.semi_span) + ] + return L_prime + + def get_lift_total(self): + F_z = [(self.lift_rectangular[_] + self.lift_elliptical[_]) / 2 + for _ in range(len(self.lift_rectangular))] + return F_z + + def get_mass_distribution(self, total_mass): + F_z = [total_mass / self.semi_span for x in range(0, self.semi_span)] + return F_z + + def get_drag(self, drag): + # Transform semi-span integer into list + semi_span = [x for x in range(0, self.semi_span)] + + # Drag increases after 80% of the semi_span + cutoff = round(0.8 * self.semi_span) + + # Drag increases by 25% after 80% of the semi_span + F_x = [drag for x in semi_span[0:cutoff]] + F_x.extend([1.25 * drag for x in semi_span[cutoff:]]) + return F_x + + def get_centroid(self): + """Return the coordinates of the centroid.""" + stringer_area = self.stringer.area + cap_area = self.spar.cap_area + + caps_x = [value for spar in self.spar.x for value in spar] + caps_z = [value for spar in self.spar.z for value in spar] + stringers_x = self.stringer.x + stringers_z = self.stringer.z + + denominator = float( + len(caps_x) * cap_area + len(stringers_x) * stringer_area) + + centroid_x = float( + sum([x * cap_area for x in caps_x]) + + sum([x * stringer_area for x in stringers_x])) + centroid_x = centroid_x / denominator + + centroid_z = float( + sum([z * cap_area for z in caps_z]) + + sum([z * stringer_area for z in stringers_z])) + centroid_z = centroid_z / denominator + + return (centroid_x, centroid_z) + + def get_inertia_terms(self): + """Obtain all inertia terms.""" + stringer_area = self.stringer.area + cap_area = self.spar.cap_area + + # Adds upper and lower components' coordinates to list + x_stringers = self.stringer.x + z_stringers = self.stringer.z + x_spars = self.spar.x[:][0] + self.spar.x[:][1] + z_spars = self.spar.z[:][0] + self.spar.z[:][1] + stringer_count = range(len(x_stringers)) + spar_count = range(len(self.spar.x)) + + # I_x is the sum of the contributions of the spar caps and stringers + # TODO: replace list indices with dictionary value + I_x = sum([ + cap_area * (z_spars[i] - self.centroid[1])**2 for i in spar_count + ]) + I_x += sum([ + stringer_area * (z_stringers[i] - self.centroid[1])**2 + for i in stringer_count + ]) + + I_z = sum([ + cap_area * (x_spars[i] - self.centroid[0])**2 for i in spar_count + ]) + I_z += sum([ + stringer_area * (x_stringers[i] - self.centroid[0])**2 + for i in stringer_count + ]) + + I_xz = sum([ + cap_area * (x_spars[i] - self.centroid[0]) * + (z_spars[i] - self.centroid[1]) for i in spar_count + ]) + I_xz += sum([ + stringer_area * (x_stringers[i] - self.centroid[0]) * + (z_stringers[i] - self.centroid[1]) for i in stringer_count + ]) + return (I_x, I_z, I_xz) + + def get_dx(self, component): + return [x - self.centroid[0] for x in component.x_start] + + def get_dz(self, component): + return [x - self.centroid[1] for x in component.x_start] + + def get_dP(self, xDist, zDist, V_x, V_z, area): + I_x = self.I_['x'] + I_z = self.I_['z'] + I_xz = self.I_['xz'] + denom = float(I_x * I_z - I_xz**2) + z = float() + for _ in range(len(xDist)): + z += float(-area * xDist[_] * (I_x * V_x - I_xz * V_z) / denom - + area * zDist[_] * (I_z * V_z - I_xz * V_x) / denom) + return z + + def analysis(self, V_x, V_z): + """Perform all analysis calculations and store in class instance.""" + self.drag = self.get_drag(10) + self.lift_rectangular = self.get_lift_rectangular(13.7) + self.lift_elliptical = self.get_lift_elliptical(15) + self.lift_total = self.get_lift_total() + self.mass_dist = self.get_mass_distribution(self.mass_total) + self.centroid = self.get_centroid() + self.I_['x'] = self.get_inertia_terms()[0] + self.I_['z'] = self.get_inertia_terms()[1] + self.I_['xz'] = self.get_inertia_terms()[2] + spar_dx = self.get_dx(self.spar) + spar_dz = self.get_dz(self.spar) + self.spar.dP_x = self.get_dP(spar_dx, spar_dz, V_x, 0, + self.spar.cap_area) + self.spar.dP_z = self.get_dP(spar_dx, spar_dz, 0, V_z, + self.spar.cap_area) + return None + + +def plot_geom(evaluator): + """This function plots analysis results over the airfoil's geometry.""" + # Plot chord + x_chord = [0, evaluator.chord] + y_chord = [0, 0] + plt.plot(x_chord, y_chord, linewidth='1') + # Plot quarter chord + plt.plot(evaluator.chord / 4, + 0, + '.', + color='g', + markersize=24, + label='Quarter-chord') + # Plot airfoil surfaces + x = [0.98 * x for x in evaluator.airfoil.x] + y = [0.98 * z for z in evaluator.airfoil.z] + plt.fill(x, y, color='w', linewidth='1', fill=False) + x = [1.02 * x for x in evaluator.airfoil.x] + y = [1.02 * z for z in evaluator.airfoil.z] + plt.fill(x, y, color='b', linewidth='1', fill=False) + + # Plot spars + try: + for _ in range(len(evaluator.spar.x)): + x = (evaluator.spar.x[_]) + y = (evaluator.spar.z[_]) + plt.plot(x, y, '-', color='b') + except AttributeError: + print('No spars to plot.') + # Plot stringers + try: + for _ in range(0, len(evaluator.stringer.x)): + x = evaluator.stringer.x[_] + y = evaluator.stringer.z[_] + plt.plot(x, y, '.', color='y', markersize=12) + except AttributeError: + print('No stringers to plot.') + + # Plot centroid + x = evaluator.centroid[0] + y = evaluator.centroid[1] + plt.plot(x, y, '.', color='r', markersize=24, label='centroid') + + # Graph formatting + plt.xlabel('X axis') + plt.ylabel('Z axis') + + plot_bound = max(evaluator.airfoil.x) + plt.xlim(-0.10 * plot_bound, 1.10 * plot_bound) + plt.ylim(-(1.10 * plot_bound / 2), (1.10 * plot_bound / 2)) + plt.gca().set_aspect('equal', adjustable='box') + plt.gca().legend() + plt.grid(axis='both', linestyle=':', linewidth=1) + plt.show() + return None + + +def plot_lift(evaluator): + x = range(evaluator.semi_span) + y_1 = evaluator.lift_rectangular + y_2 = evaluator.lift_elliptical + y_3 = evaluator.lift_total + plt.plot(x, y_1, '.', color='b', markersize=4, label='Rectangular lift') + plt.plot(x, y_2, '.', color='g', markersize=4, label='Elliptical lift') + plt.plot(x, y_3, '.', color='r', markersize=4, label='Total lift') + + # Graph formatting + plt.xlabel('Semi-span location') + plt.ylabel('Lift') + + plt.gca().legend() + plt.grid(axis='both', linestyle=':', linewidth=1) + plt.show() + return None |