Abstract
Lock stitched fabrics consist of a fabric element having length fraction φf and a seam element having length fraction φy coupled in series. It can be assumed that a stitch interval is the unit width which represents the tensile behavior of the lock stitched fabrics. The data obtained from tensile experiments with the stitched fabrics having various textures agree well with the results calculated from the tensile load-strain curves of each element on the above mentioned assumptions, when the samples are tested in the lower load region and kept in original seam forms. The tensile load-strain curves of the stitched fabrics resemble these of original fabrics. This is because φf is equal to nearly unity for usual stitched fabrics.
The breaking process for the stitched fabrics can be put into four types. The tensile ruptures of the stitched fabrics usually take place at the seam element. In this case, the seam strength efficiency can be calculated by the tensile stren th per a stitch interval of the fabrics and the loop strength of the sewing threads.
