Parametric characterization and error analysis of Hopkinson bar waveforms

The Hopkinson bar technique is an essential method for characterizing material dynamic properties. This study develops a parametric framework for stress waveform characterization, incorporating time-dependent markers ( t 0 to t 3 ), amplitude-dependent parameters (peak stress σ max , local minimum σ m , wave range Δ σ ), and specific impulse ( I ). Numerical simulations quantify assembly error effects on waveform fidelity. Key findings demonstrate: (1) The proposed parameters comprehensively define waveform morphology. Identical incident wave parameters yield transmitted waveform deviations below 0.5 %, confirming parametric consistency. (2) Incident bar eccentricity induces minimal error: At eccentricities ≤ 10 % of rod diameter, incident waveform parameter errors remain < 1 %. (3) Incident bar tilt causes significant distortion: At tilt angles ≥ 3°, waveform profiles exhibit substantial alterations, including prolonged ascent times (>155 % increase), flattened peaks, and suppressed oscillations (wave range reduction >95 % in selected elements). These results establish quantitative tolerances for Hopkinson bar alignment, emphasizing tilt control as critical for waveform integrity.