No abstract

No abstract

In this study, fabric bagging tests are performed on a set of knitted fabrics that vary in design, tightness factor, and blend ratio. The relationships between residual bagging height ( R residual ) obtained from the fabric bagging test and the mechanical characterization determined from the KES-FB system are presented and discussed. The work shows that it is possible to predict R residual for knitted fabrics by using the standard KES-FB test and without performing fabric bagging fatigue tests.

Two identically constructed cotton/polyester fabrics, one made from polyester staple core/cotton-covered yarn and the other from a random blend yarn, were evaluated for their low-stress mechanical properties and hand quality, following the objective hand evaluation approach developed by Kawabata. Heat energy dissipation through the fabrics under dry and wet contact conditions and their warm-cool contact sensations were measured using Kawabata's new "Thermolabo Device." Comparison of the low- stress mechanical properties revealed that the fabric made of polyester-core/cotton covered yam is more resilient to tensile and compressive deformation and has higher bending rigidity, lower tensile elongation, and lower shear modulus. The same fabric also gives higher values for all four primary hand qualities and for total hand quality associated with a men's summer suit application. For a women's thin dress application, it gives higher values for five out of the six primary hand qualities. It also offers a cooler contact sensation and much less variation in contact sensation along its length . compared to the fabric from the random blend yarn. The amount of heat energy dissipated through the fabric made of cotton-covered yam was lower under dry contact (nonsweating) conditions and higher under wet contact (sweating) conditions, sug gesting that this fabric may have a better thermal comfort value for cold and dry (winter) as well as hot and humid (summer) weather conditions. Energy dissipation along the fabric also varied much less for the material from cotton-covered yarn. This work not only identifies differences in the subjective properties of the fabrics in quan titative terms, but also demonstrates the value of Kawabata's methods for designing and producing superior quality apparel fabrics.

Using a modified Kawabata Thermolabo apparatus housed in a controlled envi ronmental chamber, we obtained measurements of heat transfer through a specially selected set of jersey knit textile fabrics. We then used analytical models to compute thermal comfort limits based on the experimental values and predetermined estimates of human metabolic activity. The jersey knit fabrics differed primarily on the basis of fiber content: the comparisons were between two knits, both made with 100% polyester fibers of different deniers, and a 100% cotton fabric. This research confirms the results of several previous studies that fabric structural features, not component fibers, are the most important controllers of thermal dissipation in the presence of moisture diffusion. Our results also show that heat transfer is highly related to fabric thickness, bulk density, and air volume fraction. Thermal transfer from a simulated sweating skin surface is strongly correlated with fabric porosity and air permeability.