Time, temperature, and strain effects on viscoelastic Poisson's ratio of epoxy resins

Pandini, Stefano; Pegoretti, Alessandro

doi:10.1002/pen.21060

Cited by 54 publications

(30 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…when the T g drops below the testing temperature. A similar trend was observed previously for tests at different temperatures [50], [51]. This increase in Poisson"s ratio was associated with the transition to a more rubbery behaviour as water enters and T g drops.…”

Section: T G Related Behavioursupporting

confidence: 87%

Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates

Arhant

Gac

Gall

et al. 2016

Composites Part A: Applied Science and Manufacturing

View full text Add to dashboard Cite

Thermoplastic matrix carbon fibre composites offer considerable potential for underwater applications. Various material options exist but there are questions concerning the tension/compressive behaviour and water sensitivity of the less expensive polymers (e.g. polyamides) for these applications. The aim of the current work is to model water diffusion and its effect on the mechanical properties of thick carbon fibre reinforced polyamide-6 composite cylinders immersed in sea water for deep sea applications. To provide the data for such a model, thin specimens (2 mm thick) have been aged under different humidity conditions and tested in tension and compression. As water enters the composite, a significant reduction in the laminate properties is observed. An empirical relationship that links matrix-dominated properties to water content is presented and can be used for modelling purposes.More than 70% of the oceans remain unexplored. With an average depth of over 3800 meters, it is necessary to design exploration devices that are able to withstand high hydrostatic pressures. The lighter these pressure vessels are the more equipment and measuring instruments they can carry, so composites have been used underwater for many years [1]. The use of composites for pressure hulls of underwater vehicles and submarines has been an ongoing research topic for many years, since the early work in the UK by Smith and colleagues in the 1970"s [2]. The use of glass and carbon reinforced thermoset composite materials for deep-sea applications needs a thorough understanding of the behaviour of these materials under hydrostatic pressure.However, the ability to predict the implosion pressures of such materials and under such loadings (bi-axial compression) is not an easy task, as was demonstrated by the results of the World Wide Failure Exercise [3].Applications for thick thermoplastic cylinders for underwater applications are rarer, even though there is an increasing number of thermoplastic matrix polymers available on the market such as polypropylene (PP), polyamide (PA), polyphenylene sulphide (PPS), polyetheretherketone (PEEK), etc. They offer possibilities for forming by local heating, attractive mechanical properties, good environmental resistance and the potential for end of life recycling. More ductile and reparable by melting, they offer a real potential for greatly improved devices. Studies have been conducted in the USA on carbon/PEEK cylinders [4], [5] and by the author [6] and were found to be very promising as they imploded at comparable pressures to those of their carbon/epoxy counterparts. However, it is not clear to what extent the compressive behaviour of thermoplastic composites in the presence of water will limit the operating depth of an underwater pressure vessel, especially for carbon/polyamide 6 (C/PA6) composites. The latter are attractive as they are much less expensive than composites based on high performance matrix polymers such as PEEK.The mechanical behaviour of composite materials has been extensively expl...

show abstract

Section: T G Related Behavioursupporting

confidence: 87%

Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates

Arhant

Gac

Gall

et al. 2016

Composites Part A: Applied Science and Manufacturing

View full text Add to dashboard Cite

show abstract

“…For both strain rates the inflection point of the curves is located at about 40°C, in proximity to that found for the Poisson's ratio measured at the lower strain rate. It is interesting to compare these results with those previously obtained by this group, under similar experimental methodology, on epoxy resins [14]. A similar sigmoidal dependence on temperature was evidenced for the epoxy systems, but with an inflection point for the Poisson's ratio vs. temperature curve occurring 20°C below the inflection point of the simultaneously measured Young's modulus vs. temperature curve.…”

Section: Constant Deformation Rate Testssupporting

confidence: 78%

“…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]. 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]).…”

Section: Introductionmentioning

confidence: 83%

“…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.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Pandini¹,

Pegoretti²

2011

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract. The viscoelastic nature of the Poisson's ratio of a semicrystalline poly (butylene terephthalate) is highlighted by investigating its dependence on time, temperature and strain rate, under two types of loading conditions: i) constant deformation rate tests, in which the transverse strain is measured in tensile ramps at various temperatures and at two strain rates; and ii) constant deformation tests, in which, under a constant axial deformation, the transverse strain is measured as a function of time in isothermal experiments performed at various temperatures. In both testing configurations, axial and transverse deformations are measured by means of a biaxial contact extensometer, and a correction procedure is adopted in order to compensate the lateral penetration of the extensometer knives. Poisson's ratio displays the typical features of a retardation function, increasing with time and temperature, and decreasing with strain rate. This behaviour has been compared to that of simultaneously measured relaxation modulus.

show abstract

“…(1), # is Poisson's ratio, which for epoxy varies from 0.40 to 0.45 depending upon various factors [28,29]. K IC is the fracture toughness intensity factor, which is the crack driving force calculated using Eq.…”

Section: Evaluation Of Mode I Fracture Toughness Of Matrix (G M Ic )mentioning

confidence: 99%

Improved Mode I fracture resistance of CFRP composites by reinforcing epoxy matrix with recycled short milled carbon fibre

Cholake

Moran

Joe

et al. 2016

Construction and Building Materials

View full text Add to dashboard Cite

Time, temperature, and strain effects on viscoelastic Poisson's ratio of epoxy resins

Cited by 54 publications

References 18 publications

Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates

Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates

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

Improved Mode I fracture resistance of CFRP composites by reinforcing epoxy matrix with recycled short milled carbon fibre

Contact Info

Product

Resources

About