Development of a Static Test Method To Evaluate Crashworthiness of Wheelchair Seating Systems Used as Motor Vehicle Seats

DongRan Ha, MS and G. Bertocci, PhD
Injury Risk Assessment and Prevention Laboratory
Department of Rehabilitation Science and Technology
University of Pittsburgh, Pittsburgh, PA

Slide 1
Development of a Static Test Method To Evaluate Crashworthiness of Wheelchair Seating Systems Used as Motor Vehicle Seats

DongRan Ha, MS and G. Bertocci, PhD

Injury Risk Assessment and Prevention Laboratory
Department of Rehabilitation Science and Technology
University of Pittsburgh, Pittsburgh, PA

Slide 2
Funded by

PVA, CDC-CIRCL, NIDRR RERC on Wheeled Mobility

Slide 3
Background

Americans with Disabilities Act

• More WC users rely on public transportation
  
• Many motor vehicles were modified
  

WC seats, backs, components, and frame structures may not be able to withstand the loads that can occur during crashes

Slide 4
Statement of the Problem

ANSI/RESNA WC/19 – Wheelchairs Used as Seats in Motor Vehicles

- Sled impact testing of a complete wheelchairs

- 20g/48kph (30mph) frontal crash

Substitute, replacement or optional seating systems will not be sled tested by ANSI/RESNA WC/19.

Slide 5
Objective

Development of a low cost static test method that can be used to evaluate crashworthiness of wheelchair seating systems independent of a specific wheelchair frame

Slide 6
Development of Test Criteria Loads

Seat Backs and Back Attachment Hardware:

Rear impact:

• FMVSS 207 test criterion with consideration of occupant’s weight and inertia effects
  
• 20 x (weight of the upper torso of a 50th percentile male + weight of each wheelchair seat back)
  

Rebound associated with frontal impact:

• 20g/30mph frontal impact computer crash simulation
  
• Approximately 2290 lb.
  

Slide 7
Development of Test Criteria Loads

Seats and Seat Attachment Hardware:

• Loads determined from a computer crash simulation study done by Bertocci et al.
  • 50th percentile male Hybrid III test dummy
  • 20g/30mph frontal impact
• Approximately 3750 lb
  

Slide 8
Test Apparatus Test Fixture

Two 1" diameter solid rods simulate the wheelchair frames

Rods were spaced 18" apart - represent a common adult wheelchair frames

Graphic description:

Slide 9

Graphic description of Surrogate Hardware:

Graphic description of Surrogate seat/back surface:

Slide 10
Reference Loader Gauge (RLG)

Graphic description:

Slide 11
Test Set Up

Graphic description:

Slide 12
Evaluation

Two sets of forty different types of WCSSs and components tested

• Results of the static tests showed similar failure modes observed during previously conducted sled impact testing
  
  • Seats or backs which utilized drop hook type hardware failed due to straightening of the hardware
    
  • Most sling seats and sling backs withstood the test criteria loads
    

Slide 13
Discussion

Limitations of the study :

• Static loading conditions vs. dynamic loading conditions
  
• Use of a rigid test frame, surrogate attachment hardware, and a surrogate support surface
  
• Deformation of WCSSs (Submarining)
  

Developed static test:

• Provide a preliminary screening of commonly used WCSS crashworthiness independent of specific WC frames
  
• Aid manufacturers in the design of crash-safe seating components and systems

Slide 14
Thank You for Your Attention

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Updated: March 7, 2002