The effect of seams on fabric drape.

摘要

This thesis concerns the effect of seam allowance, seam types and seam positions on drape of woven fabrics. The drape study will be divided into two dimensional (2D) and three dimensional (3D). In the 2D drape study, Peirce's cantilever concept is adopted for woven fabrics with vertical and horizontal seams. In the 3D drape study, Cusick's drape theory is adopted for the fabrics with radial and circular seams. In addition, theoretical studies of a fabric cantilever with vertical seam and horizontal seam are conducted.; From the 2D cantilever test, bending length greatly increases when a vertical seam is introduced initially. However, little increase on bending length is found when seam allowance is further increased. It is also found that bending length drops as the horizontal seam moves towards the free end. The location of a horizontal seam on a fabric strip is significant to determine the bending length. From the 3D Cusick's drape test, drape coefficient increases by the addition of radial seams. Increase in seam allowance brings little effect on increasing the drape coefficient (DC%).; Fabrics with four radial seams have a very stable and regular drape profile. The highest drape coefficient has been found when a circular seam is located just out of the pedestal. Any outward movement of the circular seam from the fabric centre causes DC% to fall.; A linear relationship of DC% and bending length has been found from the radial seams and the vertical seam of fabrics. The drape patterns of vertical and radial seams on fabrics are similar to each other with the increased seam allowance (SA). A similar drape patterns between horizontal and circular seams with the change of seam positions can also be observed.; From the theoretical investigation, the ‘'second moment of area’ of the seamed cross section and the increased fabric weight due to the increased seam allowance determine the bending behavior of a fabric strip with a vertical seam. On the other hand, deflections of a fabric cantilever with a horizontal seam at different seam positions can be evaluated by a mathematical model using force theory and moment balance method. The deflections of fabrics with a horizontal seam at different positions can be graphically presented. Calculated x and y coordinates are compared with the experimental results. Good agreements are found on y deflections.