Testing and evaluation of wheelchair caster assemblies subjected to dynamic crash loading

Area of Science:

• Biomechanics and Rehabilitation Engineering
• Product Safety and Design
• Occupant Protection Systems

Background:

• Standard wheelchair design focuses on quasi-static loads during normal use.
• Transporting wheelchairs as motor vehicle seats introduces dynamic crash forces.
• Existing wheelchair caster designs may be insufficient for crash scenarios.

Purpose of the Study:

• To evaluate the structural integrity of wheelchair caster assemblies under simulated crash conditions.
• To determine the performance limits of current wheelchair caster designs when subjected to dynamic loading.
• To assess the suitability of transport wheelchairs for use as motor vehicle seats.

Main Methods:

• Dynamic drop (DD) testing was employed to simulate crash conditions.
• Loading levels and rates were adjusted to replicate data from sled impact testing and computer crash simulations.
• Seven different wheelchair caster assemblies were subjected to rigorous testing.

Main Results:

• Five out of seven evaluated caster assemblies failed under simulated crash loads.
• Failures occurred at loads of 8,007 N or less, at dynamic loading rates.
• The results indicate a significant vulnerability in current caster designs.

Conclusions:

• Current wheelchair caster assemblies may not withstand forces encountered in motor vehicle crashes.
• Dynamic drop testing is a viable and valuable method for assessing transport wheelchair safety.
• Improvements in wheelchair design are necessary to ensure occupant safety during transport.