Spacer fabrics are widely used as mattress materials of bed and wheelchair. It is due to the fact that the special sandwich structure is effective in evenly dispersing pressure to improve pressure concentration, which prevents ulcer disease of long-term seated/lying people. However, there are few investigations on relationship between structure of spacer fabric and pressure behaviour. So, the main content dealt with in the paper was to adopt pressure pad system to measure pressure distribution behaviour of spacer fabric compressed by seated people, and pressure indices with average gradient integral, pressure peak, average pressure and contacting area were featured based on pressure nephogram. Pressure tests of varying surface stitch density, spacer filaments arrangement density and layers of spacer fabric were conducted. Experimental results showed that mattress without spacer fabric existed serious pressure concentration effect, while mattress with spacer fabric obviously improved hip pressure concentration effect. Pressure concentration effect could be well improved by increasing surface stitch density, spacer filament arrangement density and thickness. Moreover, it was a good method to produce mattress with good pressure property by combining reasonable layers of spacer fabrics to meet the same pressure-relief requirements.

Warp-knitted spacer fabrics for cushion products are in contact with different parts of human body. Surface shapes of most contacting parts can be simplified as spherical caps, while there are few reports on relationship between sphere diameter and compression property of spacer fabric. Therefore, the main content dealt with in the paper was to conduct spherical compression and simulation analysis of warp-knitted spacer fabrics. Five spherical indenters were selected and three compression indices were featured. Comparisons of compression indices results of spacer fabrics amongst five spherical indenters exhibited good relations. Moreover, spherical compression behavior was simulated by finite element method to better understand the mechanism of spherical compression deformation of warp-knitted spacer fabrics. The results that relative errors of the compression indices were all small showed a good accordance between theoretical and experimental results; then, stress distribution and displacement evolutions were analyzed to discover deformation mechanism of spacer filaments compressed. It is effective to simulate the spherical compression performance between different parts of human body and spacer fabric.

The Tekscan® pressure pad was adopted to study the pressure-relief property of spacer fabric used as a mattress, where pressure peak, average pressure and contacting area were recorded directly. In order to better analyze the pressure-relief property of spacer fabric, average gradient integral and six derivative indices were featured from a pressure map. Testing results showed that spacer fabric effectively improved the pressure concentration effect by improving contacting area and decreasing pressure peak. Comparisons of the pressure-relief property of spacer fabric demonstrated that different grade weight of the seated volunteer influenced the contacting area, average pressure and average gradient integral. Correlations between objective pressure indices and subjective pressure comfort level indicated that both pressure peak and pressure comfort level had significant relations with the three basic pressure indices and six derivative indices, and they showed higher correlations under light weight, medium weight and heavy weight. It was also found that pressure peak was a good index to effectively evaluate the pressure-relief property of spacer fabrics, and both relieving average pressure per weight and relieving average gradient integral per weight are two effective pressure indices to evaluate the pressure-relief level. It is helpful in designing the structure of spacer fabrics to improve pressure comfort.

The main content dealt with in this paper was to present an objective method to evaluate the plantar press-comfort performance of warp-knitted spacer fabrics. It aimed to explain the plantar press-comfort performance of spacer fabric by the compression property and structure parameters of spacer fabric. The compression indexes (compression work, recovery work, hysteresis work and maximum compression force) and structure parameters (diameter and thickness) were utilized to classify the plantar press-comfort performance of warp-knitted spacer fabrics by regression analysis and the K-means cluster method. In order to verify the validity, subjective judgments were also made and compared with the objective K-means cluster method. The experimental results showed that a good correlation existed between the subjective judgment method and objective cluster method. This demonstrates that the compression indexes featured, from spherical compression force–displacement curves and structure parameters, can be utilized to characterize the plantar press-comfort performance of warp-knitted spacer fabrics and is effective in obtaining the fabric evaluation score of plantar press-comfort performance.

Spacer fabrics have been developed into a variety of special textile mattress products due to their outstanding pressure distribution performance. It may be that the contacting area of spacer fabrics can be expanded under spherical compression. The total compression force and distance curve is currently used to test the compression of spacer fabrics; however, there are few detailed reports about expanding the contacting area under the spherical intender. Therefore, this paper developed a test method for the contacting area between the spacer fabric and the spherical indenter under spherical compression. The spherical indenter was specially designed by using serial resistors method. The contacting area was easily obtained by detecting the resistance change through 12 resistors pasted on the surface of the spherical indenter and calculating the surface of the spherical indenter under dynamic movement. This method can be used to effectively characterize the pressure-relief property of textile soft materials in pad materials.