Modeling the influence of grip and push force variations on the mechanical impedance and vibration power absorption of the hand-arm system

Understanding the vibration behavior of the hand-arm system (HAS) is essential for product development and occupational health. Although push and grip forces strongly influence HAS vibrations, the appropriate approach for modeling force-dependent mechanical impedance (MI) and vibration power absorption (VPA) remains unclear. This study systematically examines MI and VPA along the z h -axis for translational excitation in five subjects using 1,500 measurements across a 10 × 10 grid of push and grip force combinations, covering push forces of 10–110 N and grip forces of 10–135 N. Unlike previous studies with only few discrete force combinations, this high-resolution force grid not only enables a detailed characterization of force-dependent behavior, but also, for the first time, the systematic evaluation of interpolation-based prediction across the force domain. The results show that grip force dominates MI in the 30–70 Hz and 160–500 Hz ranges, while push force has the greatest influence between 50 Hz and 110 Hz. Higher forces generally increase VPA, but reduce it in the low-frequency range of 10–30 Hz. Compared with ISO 10068:2012, measured MI values deviate from the standardized range, especially at higher grip and push forces, reaching up to four times higher values and thereby also affecting VPA as a derived quantity. Linear interpolation using only three discrete force levels predicts MI and VPA at intermediate force levels with at least 95 % mean accuracy based on MAPE. These findings show that force-dependent HAS responses can be represented with substantially reduced experimental effort, providing a basis for physical and simulation-based models with continuously variable coupling forces.