Analysis of backward falls caused by accelerated floor movements using a dummy

Area of Science:

• Biomechanics
• Injury Prevention
• Robotics

Background:

• Understanding backward fall mechanisms is crucial for developing effective personal protective equipment.
• Previous research has not fully elucidated the impact of surface friction and acceleration on fall dynamics.

Purpose of the Study:

• To investigate the biomechanics of backward falls induced by floor acceleration.
• To determine the influence of surface properties and joint configurations on fall duration and impact velocity.
• To provide data for the design of advanced protective gear, such as wearable airbags.

Main Methods:

• A linear accelerator system was designed to simulate backward falls using a standing dummy.
• Twenty combinations of step-shaped accelerations were applied to the floor.
• Tests were conducted on both slippery (lubricated aluminum) and non-slippery (abrasive) surfaces.
• Dummy joint configurations (ankle, knee, hip) were varied between fixed and unfixed positions.

Main Results:

• Head impact velocities remained consistent at approximately 22-23 km/h when the dummy fell as a rigid body.
• Mean fall duration was 0.83 seconds on slippery surfaces and 0.98 seconds on non-slippery surfaces.
• Fall duration decreased towards 0.8 seconds with increasing floor acceleration velocity, regardless of surface friction.

Conclusions:

• Backward fall head impact velocity is largely independent of surface friction when falling as a rigid body.
• Surface friction significantly influences the duration of backward falls.
• Findings support the development of protective equipment, like wearable airbags, by providing critical impact and duration data.