Correlation of ISO 16840-2:2007 impact damping and hysteresis measures for a sample of wheelchair seating cushions

Abstract

Hysteresis and impact damping measures were made on 37 wheelchair seating cushions according to ISO 16840-2:2007 Wheelchair seating-Part 2: Determination of physical and mechanical characteristics of devices intended to manage tissue integrity-seat cushions. These measures were then correlated using Spearman and Pearson correlations to investigate the relationship between them. Correlations were also conducted on the subset of cushions comprising only those with planar foam construction. Correlation between the hysteresis measures (h 250 and h 500 ) and the mean number of rebounds greater in amplitude than 10% of the peak acceleration amplitude (R 10% ) were weak, as were the correlations between the hysteresis measures and the mean peak first rebound acceleration (a a ). Correlations between hysteresis and the mean peak second rebound acceleration (a 2 ), and also hysteresis and the ratio of first and second peak (a 2 :a a ) 1 * The authors would like to ensure that readers are aware that the term hysteresis, which is used in the ISO 16840-2:2007 version of the standard, may be substituted in future revisions.2 Corresponding author 2 however were moderate. Results demonstrate that the relationship between these two measures is complex. The assertion implicit in ISO 16840-2:2007 is that the two measures are related, but this study shows that these should not be assumed to be equivalent or used interchangeably.

Vibration Characteristics Analysis of Convalescent‐Wheelchair Robots Equipped with Dynamic Absorbers

“…In recent years, many scholars have studied the related vibration problems of wheelchair robots. e damping characteristics of the wheelchair cushion were studied on the basis of the standard ISO 16840-2:2007 in [6]. A new dynamic model for the wheelchair coupled with the user was developed and validated in [7].…”

Study of castor oil‐based auxetic polyurethane foams for cushioning applications

“…In the present work, samples of size 120 mm × 80 mm × 20 mm were made and tested. Further studies on large (seat size) foams and testing using standardized methodologies for seat cushions 45 and human trials to study pressure distribution capacity of large foams are needed. Overall, our results are encouraging and indicate a possibility of realizing low‐cost, easy‐to‐manufacture smart seat cushions that are antibacterial and provide better stress distribution and comfort to users.…”