Spectral and Temporal Constrained Waveform Synthesis for Repetitive Aircraft Shock

Accurate simulation of repetitive aircraft shock is needed to assess the environmental adaptability of aircraft equipment, especially at locations close to the excitation source. Conventional narrowband random-on-random (NOR) testing generates a stationary, approximately Gaussian waveform. Although its power spectral density (PSD) can satisfy the prescribed spectrum, it does not reproduce the high peaks, repeated pulse shape, and high kurtosis observed in near-field aircraft shock. This paper presents a time-domain windowed pulse (TDWP) synthesis method with a time-frequency joint optimization procedure. A stationary random carrier is generated from the initial PSD, and a physically motivated exponential window is used to impose the firing-rate-related pulse pattern. Windowing changes the spectrum, so a regularized spectral equalization is applied in a closed loop to bring the PSD of the final waveform back to the target spectrum. The window decay exponent is selected by minimizing errors in peak and kurtosis while enforcing PSD consistency. One set of field measurements and three laboratory tests were used for validation. Relative to the conventional method, TDWP reduced the absolute error in maximum peak, kurtosis, and fatigue-damage-equivalent response by 46.4, 51.2, and 53.9 percentage points, respectively. The results indicate that preserving the transient pulse sequence can improve the representation of near-source repetitive aircraft shock while maintaining the prescribed spectral requirement under the investigated conditions.