Creep phenomena in FRP materials

Ascione, Luigi; Berardi, Valentino Paolo; D'Aponte, Anna

doi:10.1016/j.mechrescom.2012.03.010

Cited by 70 publications

(42 citation statements)

References 7 publications

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“…With respect to the 160 • C condition, the cross-linking density returned to the initial value for unknown reasons. For the specimens exposed to elevated temperatures under loading conditions, at 25 • C, the cross-linking density of the specimens decreased by 8.0% compared with specimens without loading at 25 • C. This can be attributed to the evolution of flaws in the stressed state [28] or the chain scission of the matrix occurring under the combined effects of sustained loading and elevated temperatures [9]. Oxidation is limited on the surface of the epoxy resin, which can be attributed to the formation of carbonyl groups from the hydroxyl groups [34].…”

Section: Thermomechanical Properties Of the Resin Matrixmentioning

confidence: 96%

“…Similar to the epoxy resin, the strain is fast-growing at the initial stage, and then exhibits slow growth with time at all exposure temperatures. This can be explained by the viscoelastic theory of FRP composites due to their composition of linear elastic fibers and viscous resin matrix [9], and the stress redistribution occurring in BFRP under the effects of both elevated temperatures and constant load conditions [17]. At the initial stage, the strain increased by 92 µε for the specimens at 25 • C, and as the temperature increased to 80 • C, 120 • C, and 160 • C, the strain increased gradually by 150 µε, 852 µε, and 1034 µε, respectively.…”

Section: Creep Behavior Of Bfrpmentioning

confidence: 99%

“…After the completion of stress redistribution in BFRP specimens, the strain increases gradually with time. Due to viscoelastic characteristics of the resin matrix, elevated temperatures and sustained loading accelerated the resin matrix softening and fiber fracture [9]. Thus, exposure time at the knee point increased.…”

Section: Creep Behavior Of Bfrpmentioning

confidence: 99%

“…However, T g can be easily reached on structural surfaces directly exposed to sunlight in a typical summer climate or under fire conditions [7,8]. The creep phenomena of FRP have an important role in the reliability and durability of structural elements [9]. Numerous studies have been performed to investigate the creep behavior combined with environmental attacks on FRPs or FRP-reinforced concrete structures [4].…”

Section: Introductionmentioning

confidence: 99%

“…Most matrices have poor heat-resistant properties, and show significant creep deformation at elevated temperatures, which often lead to oxidation and failure in high-temperature environments [20]. Berardi [9] demonstrated that the stress migrates from the matrix towards the fibers in the creep process, especially at elevated temperatures, and the creep behavior of the matrices cannot be neglected for elevated temperature applications. The creep behavior of polyimides is usually described with nonlinear viscoelastic constitutive models.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Creep Behavior of Resin Matrix and Basalt Fiber Reinforced Polymer (BFRP) Plate at Elevated Temperatures

Xian

Rashid

2017

J. Compos. Sci.

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Pre-stressed fiber reinforced polymer (FRP) has great application potential in structural strengthening. However, the elevated temperature resistance of FRPs is always a key concern due to the poor thermal stability of its resin matrix. In this study, the effects of temperature on the creep behavior of the resin matrix and basalt fiber reinforced polymer (BFRP) was experimentally investigated. The tensile stresses were set at 2.6 MPa for the resin matrix and 522 MPa (35% of its ultimate tensile strength (f u )) for BFRP, and the exposure temperatures were 25 • C, 80 • C, 120 • C, and 160 • C. The short-term strain of the resin matrix and BFRP exposed to different exposure temperatures was measured. The variation of the thermal property and interlaminar shear strength (ILSS) of the BFRP were studied. The results indicated that molecular chain disruption and post-cure coexisted. The resin matrix is sensitive to the exposure temperatures, and a remarkable increase of the strain was observed when the exposure temperature exceeded its glass transition temperature (107.5 • C). The resin matrix fractured within 50 seconds when it was exposed to 160 • C. BFRP showed excellent temperature resistance even though the exposure temperature exceeded its glass transition temperature (123.7 • C). Sustained loading led to stress transferring to the basalt fiber in BFRP specimens, especially at elevated temperatures. Stress redistribution caused interfacial damage, and ILSS decreased by 0.5%, 13.6%, and 14.6% for 80 • C, 120 • C, and 160 • C exposure from its original value of 73.5 MPa. Dynamic mechanical thermal analysis (DMTA) was used to explain the post-curing and interface damage of BFRP.

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Section: Thermomechanical Properties Of the Resin Matrixmentioning

confidence: 96%

Section: Creep Behavior Of Bfrpmentioning

confidence: 99%

Section: Creep Behavior Of Bfrpmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Creep Behavior of Resin Matrix and Basalt Fiber Reinforced Polymer (BFRP) Plate at Elevated Temperatures

Xian

Rashid

2017

J. Compos. Sci.

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Creep resistance of linear low density polyethylene/carbonaceous hybrid nanocomposites: Experiments and modeling

Charitos

Kontou

2021

J of Applied Polymer Sci

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In the present work, the creep response of nanocomposites based on metallocene linear low density polyethylene (mLLDPE), reinforced with three types of carbonaceous nanofillers, namely carbon nanotubes (CNTs), graphene oxide (GO) platelets, and carbon nanofibers (CNFs) was experimentally studied. The effect of the nanofiller loading and the hybrid character of nanocomposites on the creep resistance of the nanocompsites was analyzed. In all cases, the creep resistance of the nanocomposites examined has been postulated. To support these results, creep has been modeled by a power creep law, while the creeprecovery modeling was achieved by a viscoelastic model. The implementation of the viscoelastic model has been made by assuming that the nanocomposite's structure can be represented by a physical network, with the dispersed nanofillers participating in the molecular rearrangements, which take place upon the imposition of stress. The time dependent constitutive equation involves a relaxation function, based on a Gaussian type distribution function, associated with the energy barriers that molecular segments need to overcome, for transitions to occur. It was found that creep-recovery strain could be accurately captured with the same set of parameters, whereas the number of required model parameters was quite lower than that in the widely known viscoelastic models.

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The combined effects of wet–dry cycles and sustained load on the bond behavior of FRP–concrete interface

Liang

et al. 2018

Polymer Composites

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Effective bonding between the adherents plays a key point when dealing with the retrofit of concrete structures by using fiber-reinforced polymers (FRPs). However, lack of adequate studies on the long-term performance of the bond behavior of FRP-concrete interface under harsh environments will inhibit their application in the repair of aged structures. Therefore in this study, 60 double-lap shear-bonded FRPconcrete composite specimens were designed and tested under wet-dry cycles and sustained loading. The effect of FRP type (GFRP and CFRP), wet-dry cycling times (0-360 days) and sustained loading level (0-60% of the ultimate load of the control specimen) on the failure modes, stress transfer, and local bondslip curves of the composite specimens were investigated. The experimental results showed that wet-dry cycling exposure changed the failure mode of the composite specimens from the concrete substrate to the adhesive-concrete interface, further extended the local debonding area and decreased the ultimate strains of composite specimens from 12,000 to 8,000 lE. The degree of the degradation will be further increased under the combined effect of sustained loading and wet-dry exposure. The effects of FRP type, wet-dry cycling times and sustained loading level on the fracture energy of the specimens were quantitatively analyzed. A regression model was then proposed that was able to predict the fracture energy after environment exposure with reasonable accuracy, which can provide a reference for the design of bond durability factors in relevant specifications, such as ACI 440R-08 POLYM. COMPOS., 00:000-000,

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Creep phenomena in FRP materials

Cited by 70 publications

References 7 publications

Creep Behavior of Resin Matrix and Basalt Fiber Reinforced Polymer (BFRP) Plate at Elevated Temperatures

Creep Behavior of Resin Matrix and Basalt Fiber Reinforced Polymer (BFRP) Plate at Elevated Temperatures

Creep resistance of linear low density polyethylene/carbonaceous hybrid nanocomposites: Experiments and modeling

The combined effects of wet–dry cycles and sustained load on the bond behavior of FRP–concrete interface

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