Stress—Strain Curves of Rubbers in Simple Shear

Abstract

It has been stated in a brief report that a gum rubber Hevea stock exhibited a linear stress—strain relationship in two‐dimensional shear up to 300% shear. The experimental procedures and results are reported here in detail. Detailed results are reported also of a series of dynamic stress—strain measurements with the St. Joe Flexometer, briefly referred to in 1940. These dynamic shear—shear stress curves are linear within a given stress range. Whenever the greatest previous stress is exceeded, a new linear curve is obtained, of lower modulus. Nonreversible crystallinity has been generally neglected in theories of rubber hysteresis and in experimental efforts to obtain truly reversible stress—strain curves.