Hi, Dear all, Currently try to modelling the unibixial tensile loading in some software. We know that when you stretch something, it will generate stress. Then we will have stress-strain relationship. I also read something about stretch ratio, which as defined in wikipedia "The stretch ratio or extension ratio is a measure of the extensional or normal strain of a differential line element, which can be defined at either the undeformed configuration or the deformed configuration. It is defined as the ratio between the final length ℓ and the initial length L of the material line." http://en.wikipedia.org/wiki/Deformation_(mechanics [Broken]) e(engineering strain)=λ(stretch ratio)-1. Is it reasonable for me to convert the stretch ratio data set to engineering strain for application in abaqus or ansys in engineering real application? i am worried it may have negative effect on my modelling when i do it, so need your advices. Thank you.