Anthropomorphic model rigid loading indenter with embedded sensor development for wheelchair cushion standard testing

Develop an anthropomorphic model cushion rigid loading indenter with embedded sensors (AMCRLI-ES) to assess compression and shear forces at key locations such as trochanters and ischial tuberosities. The sensor design was optimized using finite element analysis. The AMCRLI-ES was designed with the same dimensions as specified in ISO 16840-2 tests. The AMCRLI-ES is divided into eight independent sections, and each section consists of one 3-axis load cell sensor to measure compression and shear forces normal to the compression direction. Six commercial cushions were tested using the AMCRLI-ES with standard ISO 16840-2 testing procedures. Statistical differences were found for energy dissipation between cushions. Statistical differences (p < 0.001) were found in all stiffness values. Test results showed that energy dissipation (ED) was correlated with hysteresis at 500 N with moderate to high Pearson product correlation r = -0.537, p = 0.022. The hysteresis at 250 N did not show a statistical correlation with ED. The AMCRLI-ES demonstrated the ability to measure compression and shear forces at key locations on the cushion including the thigh, trochanter, ischial tuberosity, and sacral area. It provides in-depth information about how the weight was distributed on the cushions.