scholarly journals Evaluation of the mechanical response of calcarenite specimens confined with fiber reinforced polymers after high temperature exposure

2021 ◽  
Vol 42 ◽  
pp. 102504
Author(s):  
L. Estevan ◽  
F.J. Baeza ◽  
F.B. Varona ◽  
S. Ivorra
Keyword(s):  
High Temperature ◽  
Mechanical Response ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
High Temperature Exposure ◽  
Temperature Exposure

scholarly journals A strain-gradient formulation for fiber reinforced polymers: hybrid phase-field model for porous-ductile fracture

2021 ◽  
Author(s):  
M. Dittmann ◽  
J. Schulte ◽  
F. Schmidt ◽  
C. Hesch
Keyword(s):  
Ductile Fracture ◽  
Phase Field ◽  
Mechanical Response ◽  
Matrix Material ◽  
Woven Fabric ◽  
Fiber Reinforced Polymers ◽  
Gradient Theory ◽  
Fiber Reinforced ◽  
Field Methods ◽  
Reinforced Polymers

AbstractA novel numerical approach to analyze the mechanical behavior within composite materials including the inelastic regime up to final failure is presented. Therefore, a second-gradient theory is combined with phase-field methods to fracture. In particular, we assume that the polymeric matrix material undergoes ductile fracture, whereas continuously embedded fibers undergo brittle fracture as it is typical e.g. for roving glass reinforced thermoplastics. A hybrid phase-field approach is developed and applied along with a modified Gurson–Tvergaard–Needelman GTN-type plasticity model accounting for a temperature-dependent growth of voids on microscale. The mechanical response of the arising microstructure of the woven fabric gives rise to additional higher-order terms, representing homogenized bending contributions of the fibers. Eventually, a series of tests is conducted for this physically comprehensive multifield formulation to investigate different kinds and sequences of failure within long fiber reinforced polymers.

scholarly journals Effect of Exposure to High Temperature on the Mechanical Properties of SIFRCCs

2020 ◽  
Vol 10 (6) ◽  
pp. 2142
Author(s):  
Seungwon Kim ◽  
Topendra Oli ◽  
Cheolwoo Park
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
Fire Resistance ◽  
Fiber Reinforced ◽  
High Temperature Exposure ◽  
Organic Fiber ◽  
Compressive And Flexural Strengths ◽  
Temperature Exposure ◽  
Concrete Model

Many researchers have studied explosion prevention and fire resistance of high-strength concrete mixed with organic fiber and steel fibers. The fire resistance of high-performance fiber reinforced cement composites is desirable in terms of physical and mechanical properties. However, the use of a polymer as an alternative to organic fiber has not been clearly studied. In this study, a slurry infiltration method was used to obtain slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs) specimens. Powder polymer was used instead of organic fibers during mixing of the slurry. The compressive and flexural strengths of the specimens after 1 hr of high temperature exposure according to the KS F 2257 (ISO 834) standard fire-temperature curve were measured. The addition of the polymer before and after high temperature (about 945 °C) exposure affected the strength of the SIFRCCs. The compressive and flexural strengths were decreased after exposure to high temperature in comparison with SIFRCCs without polymer because polymer create capillary pores due to melting and burning when exposure to high temperature. This minimizes the vapor pressure inside the concrete model and reduces the failure of the concrete model. The experimental results showed that the flexural strength at a high temperature for 1.0 % polymer content was the highest at 53.8 MPa. The flexural strength was reduced by 40~50% when compared to the flexural strength before high temperature exposure and comparing to SIFRCCs without polymer, the compressive strength in 1.5% polymer is lower, owing to voids that are created in the SIFRCCs after exposure to a high temperature.

scholarly journals Effect of Different Environmental Conditions on the Mechanical Properties of CFRP Composites

2019 ◽  
Vol 9 (2) ◽  
pp. 2948-2951
Keyword(s):  
High Temperature ◽  
Carbon Fiber ◽  
Environmental Conditions ◽  
Weight Ratio ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Cfrp Composites ◽  
Carbon Fiber Reinforced

Carbon Fiber–Reinforced Polymers (CFRP) are extremely strong and stiff. They possess high corrosion resistance and their usage increase where rigidity and high strength-to-weight ratio are needed. Therefore they have been gaining wide usage in number of applications such as aerospace, marine, defense, civil and automobile as of their greater advantages. However the performances of these composites suffer when they are exposed to adverse environmental conditions such as moisture and high temperatures. This study work has been carried out to investigate the effect of environment on carbon composites. The primary purpose of this research study is to explore the degradation of Carbon-Fiber-Reinforced Polymers CFRP composites under various environmental conditions. The environmental conditions have been limited to influence of water uptake and high temperature in this study and the effect of environmental conditions on the tensile strength and modulus of the CFRP composites. For the very purpose, laminates of IM7/977-2 are designed and manufactured. Tensile testing on dry/wet coupons under room/high temperature conditions are conducted to investigate the degradation in strength and modulus of CFRP composites.

scholarly journals Assessing the performance of electrospun nanofabrics as potential interlayer reinforcement materials for fiber-reinforced polymers

2021 ◽  
Vol 30 ◽  
pp. 263498332110025
Author(s):  
Katerina Loizou ◽  
Angelos Evangelou ◽  
Orestes Marangos ◽  
Loukas Koutsokeras ◽  
Iouliana Chrysafi ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Polyamide 6 ◽  
Processing Parameters ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Reinforced Polymers

Multiscale-reinforced polymers offer enhanced functionality due to the three different scales that are incorporated; microfiber, nanofiber, and nanoparticle. This work aims to investigate the applicability of different polymer-based nanofabrics, fabricated via electrospinning as reinforcement interlayers for multilayer-fiber-reinforced polymer composites. Three different polymers are examined; polyamide 6, polyacrylonitrile, and polyvinylidene fluoride, both plain and doped with multiwalled carbon nanotubes (MWCNTs). The effect of nanotube concentration on the properties of the resulting nanofabrics is also examined. Nine different nanofabric systems are prepared. The stress–strain behavior of the different nanofabric systems, which are eventually used as reinforcement interlayers, is investigated to assess the enhancement of the mechanical properties and to evaluate their potential as interlayer reinforcements. Scanning electron microscopy is employed to visualize the morphology and microstructure of the electrospun nanofabrics. The thermal behavior of the nanofabrics is investigated via differential scanning calorimetry to elucidate the glass and melting point of the nanofabrics, which can be used to identify optimum processing parameters at composite level. Introduction of MWCNTs appears to augment the mechanical response of the polymer nanofabrics. Examination of the mechanical performance of these interlayer reinforcements after heat treatment above the glass transition temperature reveals that morphological and microstructural changes can promote further enhancement of the mechanical response.

scholarly journals Improving the Mechanical Response of Al–Mg–Si 6082 Structural Alloys during High-Temperature Exposure through Dispersoid Strengthening

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5295
Author(s):  
Jovid Rakhmonov ◽  
Kun Liu ◽  
Paul Rometsch ◽  
Nick Parson ◽  
X.-Grant Chen
Keyword(s):  
High Temperature ◽  
Mechanical Response ◽  
Base Alloy ◽  
Aluminum Matrix ◽  
Cost Effective ◽  
Strengthening Effect ◽  
Isothermal Exposure ◽  
High Temperature Exposure ◽  
Temperature Exposure ◽  
Strength Improvement

The feasibility and efficacy of improving the mechanical response of Al–Mg–Si 6082 structural alloys during high temperature exposure through the incorporation of a high number of α-dispersoids in the aluminum matrix were investigated. The mechanical response of the alloys was characterized based on the instantaneous high-temperature and residual room-temperature strengths during and after isothermal exposure at various temperatures and durations. When exposed to 200 °C, the yield strength (YS) of the alloys was largely governed by β” precipitates. At 300 °C, β” transformed into coarse β’, thereby leading to the degradation of the instantaneous and residual YSs of the alloys. The strength improvement by the fine and dense dispersoids became evident owing to their complementary strengthening effect. At higher exposure temperatures (350–450 °C), the further improvement of the mechanical response became much more pronounced for the alloy containing fine and dense dispersoids. Its instantaneous YS was improved by 150–180% relative to the base alloy free of dispersoids, and the residual YS was raised by 140% after being exposed to 400–450 °C for 2 h. The results demonstrate that introducing thermally stable dispersoids is a cost-effective and promising approach for improving the mechanical response of aluminum structures during high temperature exposure.

The Effect of High Temperature Exposure on Properties of Hybrid Fiber Reinforced UHPC

2017 ◽  
Vol 909 ◽  
pp. 275-279
Author(s):  
Jan Fořt ◽  
David Čítek ◽  
Milena Pavlíková ◽  
Zbyšek Pavlík
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Structural Changes ◽  
Physical And Mechanical Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
High Temperature Exposure ◽  
High Performance Fiber ◽  
Concrete Damage ◽  
Temperature Exposure

High Performance Fiber Reinforced Concrete (HPFRC) became very popular material for its high mechanical strength, elastic modulus and corrosion resistance. However, also its high-temperature resistance is of a particular importance because of the fire safety. Therefore, the effect of high-temperature exposure on UHPC reinforced by combination of steel and PVA fibers was studied in the paper. PVA fibers were used to moderate concrete damage induced by water vapor evaporation from dense UHPC matrix. The UHPFRC samples were exposed to the temperatures of 200 °C, 400 °C, 600 °C, 800 °C, and 1 000 °C respectively. Concrete structural changes induced by high temperature action were described by the measurement of basic physical and mechanical properties. The realized experiments provide information on the changes of concrete porosity and loss of mechanical resistivity.

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