modified: .gitignore

modified:   README.md
	new file:   requirement.txt
	new file:   scripts_2/README.md
	new file:   scripts_2/__init__.py
	new file:   scripts_2/__pycache__/__init__.cpython-310.pyc
	new file:   scripts_2/__pycache__/signal_utils.cpython-310.pyc
	new file:   scripts_2/__pycache__/task3_identify.cpython-310.pyc
	new file:   scripts_2/signal_utils.py
	new file:   scripts_2/task3_identify.py
	new file:   scripts_3/README.md
	new file:   scripts_3/__init__.py
	new file:   scripts_3/__pycache__/__init__.cpython-310.pyc
	new file:   scripts_3/__pycache__/task4_predict_freq.cpython-310.pyc
	new file:   scripts_3/task4_predict_freq.py
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from __future__ import annotations
import argparse
from pathlib import Path
import sys
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import numpy as np
if __package__ is None or __package__ == "":
sys.path.append(str(Path(__file__).resolve().parents[1]))
from scripts_2.signal_utils import (
TOP_RESPONSE_AXIS,
TOP_RESPONSE_SENSOR,
bandpass_filter,
detect_decay_peaks,
dominant_frequency_in_band,
ensure_parent_dir,
estimate_sampling_rate,
read_sensor_signal,
select_decay_peak_window,
)
def parse_args() -> argparse.Namespace:
project_root = Path(__file__).resolve().parents[1]
parser = argparse.ArgumentParser(description="Identify the first natural frequency and damping ratio from free-decay data.")
parser.add_argument(
"--file",
type=str,
default=str(project_root / "downloads" / "Non_TMD" / "free_vib" / "free_decay.csv"),
help="Path to a free-vibration CSV inside the dedicated free_vib folder.",
)
parser.add_argument(
"--output-dir",
type=str,
default=str(project_root / "evaluation_outputs" / "task3_identify"),
help="Directory for plots and optional exported diagnostics.",
)
parser.add_argument(
"--bandwidth",
type=float,
default=0.3,
help="Half-bandwidth (Hz) of the Butterworth band-pass filter around the identified natural frequency.",
)
parser.add_argument(
"--show",
action="store_true",
help="Display the generated figure in addition to saving it.",
)
return parser.parse_args()
def validate_free_vibration_source(file_path: Path) -> None:
if "free_vib" not in {part.lower() for part in file_path.parts}:
raise ValueError(
f"{file_path.name} is not inside a dedicated free_vib folder. Forced-vibration tails are forbidden for task 3."
)
def build_envelope_curve(
time_values: np.ndarray,
peak_times: np.ndarray,
fit_amplitudes: np.ndarray,
) -> tuple[np.ndarray, np.ndarray]:
if peak_times.size < 2:
return time_values, np.zeros_like(time_values)
envelope = np.interp(time_values, peak_times, fit_amplitudes, left=fit_amplitudes[0], right=fit_amplitudes[-1])
return time_values, envelope
def save_task3_figure(
file_path: Path,
output_dir: Path,
time_values: np.ndarray,
raw_signal: np.ndarray,
filtered_signal: np.ndarray,
peak_indices: np.ndarray,
selected_peak_indices: np.ndarray,
selected_peak_amplitudes: np.ndarray,
fit_amplitudes: np.ndarray,
natural_frequency_hz: float,
damping_ratio: float,
) -> Path:
output_dir = ensure_parent_dir(output_dir)
peak_times = time_values[selected_peak_indices]
envelope_time, envelope = build_envelope_curve(time_values, peak_times, fit_amplitudes)
fig, axes = plt.subplots(3, 1, figsize=(12, 10), sharex=False)
fig.suptitle(f"Task 3 | Free-Vibration Identification | {file_path.name}")
axes[0].plot(time_values, raw_signal, color="tab:gray", linewidth=1.0, label="Raw top response")
axes[0].set_title(f"Top Response ({TOP_RESPONSE_SENSOR} / {TOP_RESPONSE_AXIS})")
axes[0].set_ylabel("Acceleration")
axes[0].grid(True, alpha=0.25)
axes[0].legend()
axes[1].plot(time_values, filtered_signal, color="tab:blue", linewidth=1.0, label="Band-pass filtered")
axes[1].scatter(time_values[peak_indices], filtered_signal[peak_indices], color="tab:orange", s=14, label="Detected peaks")
axes[1].set_title(f"Filtered around f_n = {natural_frequency_hz:.4f} Hz")
axes[1].set_ylabel("Acceleration")
axes[1].grid(True, alpha=0.25)
axes[1].legend()
axes[2].plot(time_values, filtered_signal, color="tab:blue", linewidth=1.0, alpha=0.65, label="Filtered signal")
axes[2].scatter(peak_times, selected_peak_amplitudes, color="tab:red", s=28, label="Selected envelope peaks")
axes[2].plot(envelope_time, envelope, color="tab:green", linewidth=1.8, label="Fitted positive envelope")
axes[2].plot(envelope_time, -envelope, color="tab:green", linewidth=1.2, linestyle="--", label="Fitted negative envelope")
axes[2].set_title(f"Selected decay segment | damping ratio zeta = {damping_ratio:.5f}")
axes[2].set_xlabel("Time (s)")
axes[2].set_ylabel("Acceleration")
axes[2].grid(True, alpha=0.25)
axes[2].legend()
plt.tight_layout()
figure_path = output_dir / f"{file_path.stem}_task3_identify.png"
plt.savefig(figure_path, dpi=180, bbox_inches="tight")
return figure_path
def analyze_free_vibration(
file_path: Path,
output_dir: Path,
bandwidth_hz: float = 0.3,
show: bool = False,
) -> dict[str, float | int | str | Path]:
file_path = Path(file_path).resolve()
validate_free_vibration_source(file_path)
time_values, raw_signal = read_sensor_signal(file_path, sensor_code=TOP_RESPONSE_SENSOR, value_column=TOP_RESPONSE_AXIS)
sampling_rate = estimate_sampling_rate(time_values)
natural_frequency_hz, freqs, magnitudes, peak_index = dominant_frequency_in_band(
raw_signal,
sampling_rate=sampling_rate,
min_hz=0.1,
max_hz=5.0,
zero_padding_factor=16,
)
filtered_signal = bandpass_filter(
raw_signal,
sampling_rate=sampling_rate,
center_hz=natural_frequency_hz,
bandwidth_hz=bandwidth_hz,
order=4,
)
peak_indices = detect_decay_peaks(filtered_signal, sampling_rate=sampling_rate, frequency_hz=natural_frequency_hz)
peak_window = select_decay_peak_window(filtered_signal, peak_indices, sampling_rate=sampling_rate)
selected_peak_indices = np.asarray(peak_window["peak_indices"], dtype=int)
selected_peak_amplitudes = np.asarray(peak_window["peak_amplitudes"], dtype=np.float64)
fit_amplitudes = np.asarray(peak_window["fit_amplitudes"], dtype=np.float64)
log_decrements = np.log(selected_peak_amplitudes[:-1] / selected_peak_amplitudes[1:])
mean_log_decrement = float(np.mean(log_decrements))
damping_ratio = float(mean_log_decrement / (2.0 * np.pi))
damping_ratio_exact = float(
mean_log_decrement / np.sqrt((2.0 * np.pi) ** 2 + mean_log_decrement**2)
)
figure_path = save_task3_figure(
file_path=file_path,
output_dir=output_dir,
time_values=time_values,
raw_signal=raw_signal,
filtered_signal=filtered_signal,
peak_indices=peak_indices,
selected_peak_indices=selected_peak_indices,
selected_peak_amplitudes=selected_peak_amplitudes,
fit_amplitudes=fit_amplitudes,
natural_frequency_hz=natural_frequency_hz,
damping_ratio=damping_ratio,
)
if show:
plt.show()
plt.close("all")
return {
"file_path": str(file_path),
"sensor_code": TOP_RESPONSE_SENSOR,
"axis": TOP_RESPONSE_AXIS,
"sampling_rate_hz": float(sampling_rate),
"natural_frequency_hz": float(natural_frequency_hz),
"fft_peak_bin_hz": float(freqs[peak_index]),
"fft_peak_magnitude": float(magnitudes[peak_index]),
"detected_peak_count": int(len(peak_indices)),
"selected_peak_count": int(len(selected_peak_indices)),
"mean_log_decrement": mean_log_decrement,
"damping_ratio": damping_ratio,
"damping_ratio_exact": damping_ratio_exact,
"envelope_r2": float(peak_window["r_squared"]),
"figure_path": str(figure_path),
}
def print_report(result: dict[str, float | int | str | Path]) -> None:
print("=== Task 3: Structural Dynamic Identification ===")
print(f"Input file: {result['file_path']}")
print(f"Top response sensor: {result['sensor_code']} / {result['axis']}")
print(f"Sampling rate: {result['sampling_rate_hz']:.4f} Hz")
print(f"Natural frequency f_n: {result['natural_frequency_hz']:.6f} Hz")
print(f"Mean log decrement delta: {result['mean_log_decrement']:.6f}")
print(f"Damping ratio zeta (delta / 2pi): {result['damping_ratio']:.6f}")
print(f"Damping ratio exact: {result['damping_ratio_exact']:.6f}")
print(f"Detected peaks: {result['detected_peak_count']}")
print(f"Selected peaks for envelope: {result['selected_peak_count']}")
print(f"Envelope linearity R^2: {result['envelope_r2']:.6f}")
print(f"Figure saved to: {result['figure_path']}")
def main() -> None:
args = parse_args()
result = analyze_free_vibration(
file_path=Path(args.file),
output_dir=Path(args.output_dir),
bandwidth_hz=float(args.bandwidth),
show=bool(args.show),
)
print_report(result)
if __name__ == "__main__":
main()