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177 lines
4.5 KiB
Python
177 lines
4.5 KiB
Python
from tutor_init import *
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import itertools
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# import sys
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log = logging.getLogger(__name__)
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log.setLevel(logging.DEBUG)
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MARKERS = ('o', 'x', '+', '.', '<', '>', '^', 'v')
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def plot_varying_symbols(x, y, color='red', size=5):
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"""
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Create a plot with varying symbols
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Parameters
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----------
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x : numpy array with x data of the points
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y : numpy array with y data of the points
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color : color of the symbols
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Returns
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-------
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"""
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markers = itertools.cycle(MARKERS)
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for q, p in zip(x, y):
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plt.plot(q, p, marker=markers.next(), linestyle='', color=color,
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markersize=size)
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def damage_vs_S(S, beta, K):
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"""
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Calculate the damage 1/N for a given stress S
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Parameters
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----------
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S : Stress [Pa]
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beta : coefficient, typically 3
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K : constant
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Returns
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-------
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"""
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return K * np.power(S, beta)
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# Section 4.3.1 Crossing intensity
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# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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import wafo.data as wd
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import wafo.objects as wo
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import wafo.misc as wm
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xx_sea = wd.sea()
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Tlength = xx_sea[-1, 0] - xx_sea[0, 0]
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beta = 3
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K1 = 6.5e-31
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Np = 200
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Tp = Tlength / Np
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A = 100e6
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log.info("setting sin wave with Tp={} and T={}".format(Tp, Tlength))
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Nc = 1.0 / damage_vs_S(A, beta, K1)
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damage = float(Np) / float(Nc)
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log.info("budget at S={} N={}: damage = {} ".format(A, Nc, damage))
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#xx_sea[:, 1] = A * np.cos(2 * np.pi * xx_sea[:, 0]/Tp)
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xx_sea[:, 1] *= 500e6
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log.info("loaded sea time series {}".format(xx_sea.shape))
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ts = wo.mat2timeseries(xx_sea)
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tp = ts.turning_points()
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mM = tp.cycle_pairs(kind='min2max')
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Mm = tp.cycle_pairs(kind='max2min')
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lc = mM.level_crossings(intensity=True)
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T_sea = ts.args[-1] - ts.args[0]
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# for i in dir(mM):
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# print(i)
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ts1 = wo.mat2timeseries(xx_sea[:, :])
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tp1 = ts1.turning_points()
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sig_tp = ts.turning_points(h=0, wavetype='astm')
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try:
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sig_cp = sig_tp.cycle_astm()
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log.info("Successfully used cycle_astm")
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except AttributeError:
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log.warning("Could use cycle_astm")
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sig_cp = None
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tp1 = ts1.turning_points()
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tp2 = ts1.turning_points(wavetype='Mw')
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mM1 = tp1.cycle_pairs(kind='min2max')
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Mm1 = tp1.cycle_pairs(kind='max2min')
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tp_rfc = tp1.rainflow_filter(h=100e6)
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mM_rfc = tp_rfc.cycle_pairs()
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try:
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mM_rfc_a = tp1.cycle_astm()
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except AttributeError:
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mM_rfc_a = None
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tc1 = ts1.trough_crest()
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min_to_max = True
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rfc_plot = True
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if min_to_max:
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m1, M1 = mM1.get_minima_and_maxima()
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i_min_start = 0
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else:
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m1, M1 = Mm1.get_minima_and_maxima()
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i_min_start = 2
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m_rfc, M_rfc = mM_rfc.get_minima_and_maxima()
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# m_rfc_a, M_rfc_a = mM_rfc_a.get_minima_and_maxima()
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ts1.plot('b-')
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if rfc_plot:
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plot_varying_symbols(tp_rfc.args[0::2], m_rfc, color='red', size=10)
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plot_varying_symbols(tp_rfc.args[1::2], M_rfc, color='green', size=10)
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else:
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plot_varying_symbols(tp.args[i_min_start::2], m1, color='red', size=10)
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plot_varying_symbols(tp.args[1::2], M1, color='green', size=10)
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set_windows_title("Sea time series", log)
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plt.figure()
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plt.subplot(122),
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mM.plot()
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plt.title('min-max cycle pairs')
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plt.subplot(121),
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mM_rfc.plot()
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title = 'Rainflow filtered cycles'
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plt.title(title)
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set_windows_title(title)
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# Min-max and rainflow cycle distributions
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#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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# import wafo.misc as wm
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ampmM_sea = mM.amplitudes()
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ampRFC_sea = mM_rfc.amplitudes()
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plt.figure()
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title = "s_n_curve"
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set_windows_title(title)
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S = np.linspace(1e6, 1000e6)
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plt.loglog(S, damage_vs_S(S, beta, K1))
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plt.figure()
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plt.subplot(121)
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stress_range = (1, 1e9)
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n_bins = 100
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wm.plot_histgrm(ampmM_sea, bins=n_bins, range=stress_range)
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plt.xlim(stress_range)
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ylim = plt.gca().get_ylim()
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plt.title('min-max amplitude distribution')
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plt.subplot(122)
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if sig_cp is not None:
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wm.plot_histgrm(sig_cp[:, 0], bins=n_bins, range=stress_range)
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plt.gca().set_ylim(ylim)
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title = 'Rainflow amplitude distribution'
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plt.title(title)
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plt.semilogy
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set_windows_title(title)
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hist, bin_edges = np.histogram(
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sig_cp[
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:, 0], bins=n_bins, range=stress_range)
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plt.figure()
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title = "my_bins"
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plt.title(title)
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plt.title(title)
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set_windows_title(title)
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plt.semilogy
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plt.bar(bin_edges[:-1], hist, width=stress_range[1] / n_bins)
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print("damage min/max : {}".format(mM_rfc.damage([beta], K1)))
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damage_rfc = K1 * np.sum(sig_cp[:, 0] ** beta)
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print("damage rfc : {}".format(damage_rfc))
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plt.show('hold')
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