The Classification of the Stress-Strain Curve Zones on the Basis of their Validity to Study the Shape Memory Effect (SME) Property

Abstract

This study attempts to emphasize a pre-step for determining the permitted deformations (strains) extents. This is for changing the original molecular architecture shape for the materials understudy (rubber band/stearic acid (RB/based SA) and Rubber band without stearic acid (RB without SA)). It is necessary as a basic controlling step in the choosing process of the appropriate programming method to show the shape memory effect (SME) property. By this property, the polymers are either described as shape memory effect (SME) or conventional polymers. If the material was proved to have the shape memory effect (SME) property, then it will be allowed to predict many thermo-mechanical properties. So for these materials, the (stress-strain) curve zones have been classified according to the ability of the deformation history memory, which can be erased and programmed again after the immediate removement of the applied tensile force. This can be achieved by calculating the residual strain ratio. The comparative results showed that the elastic and plateau zones were classified respectively as valid for the study of the (SME) property. While for the Hardening strain and fracture zones, they were classified as bad and very bad respectively for the study of this property.