Damage boundary spectrum of pelvis-lumbar spine of seated human under vertical wide-band shock environment

The assessment methods of personnel damage under real shock environments are still an issue. In this paper, a damage boundary for vibration-impact injury in a wide range of frequency domain based on pseudo-velocity shock spectrum (PVSRS) is first proposed with numerical simulation. A high-fidelity three-dimensional finite element (FE) model of pelvis-lumbar spine (P-LS) that the vulnerable organs of seated human under vertical impact conditions, was developed and validated. The random and complex impact loads in real environments were simplified to a series of sinusoidal accelerations with a single frequency and within one period, next loading those equivalent loads on P-LS FE model in vertical direction for batch computing. The results indicated that there is a certain critical failure load that can cause initial damage to P-LS for a specific single frequency. The injury patterns of P-LS show significant frequency sensitivity. The P-LS damage boundary can be obtained from the envelope curve of critical failure loads in PVSRS, which is a V-shaped curve and the frequency corresponding to the trough (18 Hz) is the first natural frequency of the coupled P-LS structures. The asymptote lines of damage boundary are highly consistent with that of theoretical results. The damage boundaries after classifying and standardizing, which rationality in wideband is verified by underwater explosion test data, show more comprehensive and advanced potentials for engineering application.