Browsing by Author "Shen L."

Now showing 1 - 3 of 3

Analysis of Sitting Pressure Distribution on Office Chair for Occupants with Different Body Mass Index
(2021-01-01) Li X.; Zhang T.; Shen L.; Tor O.; Zhu Y.; Zhang J.; Chilufya C.; Yan B.; Hu L.
The pressure distribution is one of popular objective measurements for sitting comfort, but a few studies were found for the pressure distribution between subjects with different body mass index and office chair. The effects of sitting posture, body mass index, gender, and the types of office chair (adjustable and non-adjustable) on sitting pressure distribution were investigated in this study. 18 subjects with different body mass indexes (overweight, normal weight and under weight) completed five different sitting postures in the order of forward-watching screen, forward-writing, backward-typing, backward-bow one’s head, and backward-cross legged. The outcome demonstrated that the seat adjustable or not, the type of sitting posture has significant influence on the average pressure, maximum pressure gradient and pressure distribution uniformity. Gender and body mass index have significant effects on the circular pressure gradient. Results of sitting pressure distribution obtained in this research, could strengthen the particularity of the body shape consideration in the design of office chairs.
Cushioning Capability Analysis of Seat Foundations Considering the Sitter’s Anthropometric Dimensions
(2020-01-01) Hu L.; Tor O.; Shen L.; Zhang J.; Quin F.; Yu X.
Sitting comfort is primarily determined by the cushioning capability of the seat foundation. Limited literature has been found related to the effects that different sized human buttocks had on the cushioning capability of the seat foundation. Moreover, there is no testing method specialized to measure the load-deformation behavior of foam cushions that imitates the sitting behavior between indenters with different sizes and seat support. This study investigated the effects of various indenter diameters (20 cm, 30 cm, 36 cm, 41 cm, 51 cm, and 58 cm), foam stiffness levels (high and low), and seat bases (spring versus solid flat panel) on the compressive load-deformation behavior of upholstered seat foundations. The load-deformation curves of all the tested foam-seat base combinations exhibited three typical regions, i.e., linear elasticity, plateau, and densification, when subjected to the loads applied through different indenter diameters. Statistical results indicated that the primary effects of the indenter diameter, foam stiffness level, and seat base had significant effects on the spring constants, which represented the slopes of lines in these three regions. In addition, a regression technique was proposed to derive power equations for the estimation of the spring constants of a seat foundation as a function of the indenter diameter, foam material stiffness, and seat base type.
Support factor of upholstered seat cushions
(2020-01-01) Zhu Y.; Shen L.; Tor O.; Zhang J.; Liu L.; Yu X.; Hu L.
Polyurethane foams are commonly used in the upholstered seat cushions, providing a sitter with a comfort sitting experience. According to the foam testing standard of American association for material testing, the compression testing for sofa cushions with two layers of foam were conducted to investigate the effects of the elastic modulus of upper and lower foams on the support factor of seat cushion. The results indicated that the interaction of elastic modulus of upper and lower foams has significant influence on support factor. The support factor is significant higher when the foam with elastic modulus of 0.19 MPa was used as the upper layer, which means those foam cushions had good support performance. In addition, a regression technique was proposed to drive power equation for the estimation of support factor as a function of elastic modulus of upper and lower foams for sofa seat cushion.