Non-linear viscoelastic behavior of polymer melts interpreted by fractional viscoelastic model

Meccanica ◽  
2016 ◽  
Vol 52 (8) ◽  
pp. 1843-1850 ◽  
Author(s):  
Salvatore Di Lorenzo ◽  
Mario Di Paola ◽  
Francesco Paolo La Mantia ◽  
Antonina Pirrotta
Keyword(s):  
Polymer Melts ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Non Linear ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic

Viscoelastic Behavior of Carbon Nanotube Yarns and Twisted Coils

2018 ◽  
Author(s):  
Pouria Khanbolouki ◽  
Mehran Tehrani
Keyword(s):  
Carbon Nanotube ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Energy Harvesters ◽  
Linear Behavior ◽  
Non Linear ◽  
Stretchable Conductors ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Development And Validation

Coiled structures made from polymer and Carbon Nanotube (CNT) yarns are used as artificial muscles, stretchable conductors, and energy harvesters. The purpose of this work is to present our latest understanding of the mechanical behavior of these CNT-based structures. CNT yarns are fabricated by inserting twists in sheets spun from CNT forests. Over twisting the CNT yarns results in coiled CNT yarns, similar to a spring where the spring radius is comparable to the diameter of the CNT yarn. In this study, we explain the development and validation of a viscoelastic model, to capture damping and hysteresis in CNT yarns under quasi-static and dynamic loads. Confirmation of linear viscoelastic behavior of CNT yarns can lead us to the development of a model for coiled CNT yarns. Coiled CNT yarns, on the other hand, show a complex non-linear viscoelastic behavior. Possible mechanisms responsible for this non-linear behavior are discussed.

Non-linear viscoelastic behavior of fumed silica suspensions

1999 ◽  
Vol 38 (1) ◽  
pp. 14-25 ◽  
Author(s):  
F. Yziquel ◽  
P. J. Carreau ◽  
P. A. Tanguy
Keyword(s):  
Fumed Silica ◽  
Viscoelastic Behavior ◽  
Non Linear ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Silica Suspensions

Non-Linear Viscoelastic Mechanics of Native and Engineered Ligaments and Tendons

2011 ◽  
Author(s):  
Jinjin Ma ◽  
Ellen M. Arruda
Keyword(s):  
Cruciate Ligament ◽  
Viscoelastic Behavior ◽  
Biomechanical Properties ◽  
Acl Graft ◽  
Non Linear ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Anterior Cruciate ◽  
Acl Replacement

Patellar tendon (PT) autografts and allografts are the most common methods currently used to replace a torn anterior cruciate ligament (ACL). The PT is not only much stiffer than the ACL it replaces it also exhibits qualitatively and quantitatively different non-linear viscoelastic behavior from those of the ACL. These mis-matched biomechanics may be contributing to the high incidence of early onset osteoarthritis suffered by patients who have had ACL surgeries. Thus there is a need for an ACL graft that can reproduce normal ligament biomechanics and knee function. This talk examines the inhomogeneous, non-linear viscoelastic response of native ACL and of a tissue engineered ACL graft designed to rapidly grow and remodel in vivo to restore the proper biomechanical properties of native ligament. The results using this graft as an ACL replacement are compared against those using a PT autograft for the ACL replacement. Uniaxial loading reveals that after nine months as an ACL replacement, the tissue-engineered graft develops a strain contour pattern closely resembling that of native ACL whereas the PT graft fails to similarly remodel in vivo.

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