To discuss the extension behavior of warp knit fabrics, we must investigate the extension behavior of their loops. We made experiments both on our model loop and on knit fabrics according to Grosberg's, theory on the extension behavior of loops with the following results.
(1) Grosberg's theoretical expression is fully reliable so far as the model loop is concerned
(2) However, his expression is not always reliable as to the extension of the knit fabrics, because their extension is much influenced by their structure. The experimental . value of half the structure agrees well with their theoretical value if the extension is low. The experimental value of denbigh structure, however, differes considerably from their theoretical value. Therefore, Grosberg's theoretical expression is inapplicable just as it is. The experimental value of an individual loop agrees comparatively well with its theoretical value if the extension is low.
From the above observations we are satisfied that Grosberg's theory is quite applicable to practical use if the fabric tension is low.