Abstract
Mechanical tests were performed in the pre-necking domain of polypropylene (PP) to characterize its mechanical behavior. Test results have distinctly characterized both its viscoelastic and its viscoplastic behavior. The usual approach to studying metals was adopted to investigate the effect of heterogeneities on the different features of the viscoplastic behavior of the polymer. Particular developments were necessary to adapt these methods to the semicrystalline polypropylene. By the macroscopic approach initially introduced by Cottrell, the macroscopic stress was split into an effective stress and a back stress so that the interactions between the crystalline lamellae and the amorphous phase could be taken into account. The modeling of the viscoelastoplastic behavior of PP is described by using the partition of total strain into a viscoelastic strain and a viscoplastic strain. The rheological model of Zener was used and improved with the experimental observations to model the viscoelastic behavior. As for viscoplastic behavior modeling, it's based on the characterization of the mechanical behavior in terms of effective stress and back stress associated with incompatibilities of deformation.
Highlights
INTRODUCTIONIn a relatively recent economic analysis [1], a new classification of polymer products according to their life span is proposed
Polymers are an integral part of our daily life
Some uniaxial mechanical tests have permitted to reveal the presence of a viscoelastic domain, of a viscoplastic domain in the pre-necking domain of PP
Summary
In a relatively recent economic analysis [1], a new classification of polymer products according to their life span is proposed They can be classified into three parts: – disposable products intended to disappear before one year; – durable goods intended to last, used between one and twenty years; – infrastructures whose life span is superior to twenty years. This analysis forecasts an increasing world production of polymers in the future years as well in industrial countries as in developing countries. Tools specific to metals are employed to characterize the heterogeneities of the biphased material Based on these considerations, a model is proposed to describe the mechanical behavior of PP under a few loading paths [2]. Numerous papers deal with the mechanical behavior of highly strained SCPs whereas polymers are in most cases subjected to small strains
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
