An experimental technique for complete dynamic characterization of a viscoelastic material

Time and temperature effects on Poisson’s ratio of poly(butylene terephthalate)

“…Finally, the data obtained from the Poisson's ratio measured in CDR experiments, shows an intermediate behavior, exhibiting values close to those measured for the moduli functions for temperature up to 40°C, while a deviation is exhibited for higher temperatures, with a slope similar to that shown by the # REL set of data. Previous literature data have always shown that the shift factors required for the Poisson's ratio master curve construction are the same as those obtained for other viscoelastic functions [10,17,20]. The difference found between master curves distribution and between the related shift factors are effects not fully understood, and that could be tentatively ascribed to an interference due to the contact extensometer.…”

“…In a work on epoxy resins we have also reported Poisson's ratio as increasing with time, temperature and strain, and decreasing with strain rate [14]. Moreover, a decreasing trend has been reported for the complex Poisson's ratio with frequency under dynamic conditions (Kästner and Pohl on PMMA [23]; Caracciolo and coworkers on poly(vinylchloride) (PVC) [19][20]; Arzoumanidis and Liechti on a neat urethane adhesive (Ashland) [21]; Pritz, by indirect methodology, on rubbery materials and PMMA [24]). The results are consistent to what predicted by analytical approaches, which describe the viscoelastic Poisson's ratio following an increasing trend with time [2,4,8], featuring the typical trend of a retardation process that can be approached as a transverse creep compliance [25].…”

“…Direct measurements of Poisson's ratio has been carried out on polymeric materials by different types of experiments, in which the axial deformation was applied through a constant rate loading ramp [12][13][14][15], under a constant load (creep) [13,[16][17], under constant strain (stress relaxation) [10,14,18], or under sinusoidal loading-unloading (dynamicmechanical analysis) [19][20][21]. An accurate measurement of the transverse strains is of crucial importance and various techniques have been employed, such as optical methods (i.e.…”

“…An accurate measurement of the transverse strains is of crucial importance and various techniques have been employed, such as optical methods (i.e. Moirè interferometry [10,[17][18] and video extensometry [13,16]), bonded strain gages [19][20] [22]). In a work on epoxy resins we have also reported Poisson's ratio as increasing with time, temperature and strain, and decreasing with strain rate [14].…”

Vibration analysis techniques for detecting filler-matrix decohesion in composites

“…For example, in (Soula et al, 1997), an inversion method adapted to wide frequency bands has been proposed and validated by experimental results on elastomers. (Pintelon et al, 2004) and (Caracciolo et al, 2004) present experimental methods for characterizing viscoelastic materials based on dynamic analysis of beams. (Kergourlay, 2004) has focused on the identification of mechanical damping for these materials.…”