Modeling the human body/seat system in a vibration environment.

Area of Science:

• Biomechanics
• Human-body dynamics
• Vibration analysis

Background:

• Human tolerance to vibration is limited by body dynamics.
• Understanding seated human body/seat system dynamics is crucial for comfort and safety.

Purpose of the Study:

• To develop a multi-degrees-of-freedom lumped parameter model for seated human body dynamics in vibration environments.
• To provide an analytical tool for human body dynamics research and seat/cushion design.

Main Methods:

• Developed a lumped parameter model incorporating global human dynamics (apparent mass phenomenon) and local human dynamics (pelvis/seat interface).
• Systematically set model parameters for various conditions (posture, muscle tension, vibration direction).
• Utilized a cushioning interface to represent human pelvis/vibrating seat contact.

Main Results:

• The model successfully described the apparent mass phenomenon, aligning with existing experimental data.
• Design guidelines for composite cushions were developed, focusing on quasi-uniform body/seat contact force distribution.
• A two-layer, three-material cushion geometry demonstrated optimal force distribution.

Conclusions:

• The lumped parameter model effectively analyzes the human/seat interface system under dynamic conditions.
• The model provides practical insights for designing protective seating and cushioning systems.
• Combining geometric and mechanical characteristics in the model enhances analysis of human-body interaction in dynamic environments.