Predicting the tensile strength and creep-rupture behaviour of pultruded glass-reinforced polymer rods

1992 ◽  
Vol 27 (18) ◽  
pp. 4899-4908 ◽  
Author(s):  
L. Franke ◽  
H. -J. Meyer
Keyword(s):  
Tensile Strength ◽  
Creep Rupture ◽  
Reinforced Polymer ◽  
Polymer Rods

Utilizing alkali-activated materials as ordinary Portland cement replacement to study the bond performance of fiber-reinforced polymer bars in seawater sea-sand concrete

2022 ◽  
pp. 136943322110651
Author(s):  
Ruiming Cao ◽  
Bai Zhang ◽  
Luming Wang ◽  
Jianming Ding ◽  
Xianhua Chen
Keyword(s):  
Tensile Strength ◽  
Bond Strength ◽  
Ordinary Portland Cement ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Bond Performance ◽  
Reinforced Polymer ◽  
Sea Sand ◽  
Frp Bars ◽  
Alkali Activated

Alkali-activated materials (AAMs) are considered an eco-friendly alternative to ordinary Portland cement (OPC) for mitigating greenhouse-gas emissions and enabling efficient waste recycling. In this paper, an innovative seawater sea-sand concrete (SWSSC), that is, seawater sea-sand alkali-activated concrete (SWSSAAC), was developed using AAMs instead of OPC to explore the application of marine resources and to improve the durability of conventional SWSSC structures. Then, three types of fiber-reinforced polymer (FRP) bars, that is, basalt-FRP, glass-FRP, and carbon-FRP bars, were selected to investigate their bond behavior with SWSSAAC at different alkaline dosages (3%, 4%, and 6% Na2O contents). The experimental results manifested that the utilization of the alkali-activated binders can increase the splitting tensile strength ( ft) of the concrete due to the denser microstructures of AAMs than OPC pastes. This improved characteristic was helpful in enhancing the bond performance of FRP bars, especially the slope of bond-slip curves in the ascending section (i.e., bond stiffness). Approximately three times enhancement in terms of the initial bond rigidity was achieved with SWSSAAC compared to SWSSC at the same concrete strength. Furthermore, compared with the BFRP and GFRP bars, the specimens reinforced with the CFRP bars experienced higher bond strength and bond rigidity due to their relatively high tensile strength and elastic modulus. Additionally, significant improvements in initial bond stiffness and bond strength were also observed as the alkaline contents (i.e., concrete strength) of the SWSSAAC were aggrandized, demonstrating the integration of the FRP bars and SWSSAAC is achievable, which contributes to an innovative channel for the development of SWSSC pavements or structures.

scholarly journals Experimental investigation of the microstructures and tensile properties of polyacrylonitrile-based carbon fibers exposed to elevated temperatures in air

2019 ◽  
Vol 14 ◽  
pp. 155892501985001 ◽  
Author(s):  
Chenggao Li ◽  
Guijun Xian
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Elevated Temperatures ◽  
Tensile Modulus ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The elevated temperature resistance and even fire resistance of carbon fiber-reinforced polymer composites were critical concerns in many applications. These properties of a carbon fiber-reinforced polymer depend not only on the degradation of the polymer matrix but also on that of the carbon fibers under elevated temperatures. In this study, influences of elevated temperatures (by 700°C for 30 min) in air on the mechanical properties and microstructures of a carbon fiber were investigated experimentally. It was found that the tensile strength and modulus as well as the diameters of the carbon fibers were reduced remarkably when the treatment temperatures exceeded 500°C. At the same time, the content of the structurally ordered carbonaceous components on the surface of carbon fibers and the graphite microcrystal size were reduced, while the graphite interlayer spacing ( d002) was enhanced. The deteriorated tensile modulus was attributed to the reduced graphite microcrystal size and the reduced thickness of the skin layer of the carbon fiber, while the degraded tensile strength was mainly attributed to the weakened cross-linking between the graphite planes.

Modelling of the electromechanical impedance technique for prediction of elastic modulus of structural adhesives

2020 ◽  
pp. 147592172091692
Author(s):  
Zi Sheng Tang ◽  
Yee Yan Lim ◽  
Scott T Smith ◽  
Ricardo Vasquez Padilla
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Model Updating ◽  
Dynamic Elastic Modulus ◽  
Curing Process ◽  
Electromechanical Impedance ◽  
Structural Adhesives ◽  
Reinforced Polymer ◽  
Impedance Technique ◽  
Fibre Reinforced Polymer

In order to strengthen and repair existing concrete structural elements, fibre-reinforced polymer composites are often externally bonded using structural adhesives. It is thus desirable to monitor the in situ performance of the sandwiched adhesive layer in such fibre-reinforced polymer–strengthened systems via its stiffness and strength gain throughout the curing process. The electromechanical impedance technique, which relies upon the utilisation of piezoelectric sensors, offers this capability. Although the technique has been verified experimentally in the laboratory, no known electromechanical impedance–based modelling study has been reported. This study, therefore, proposes the first electromechanical impedance–based finite element and analytical models to monitor the curing of structural adhesives. The dynamic elastic modulus of structural adhesives during curing can be determined from the developed models via a model updating process. Semi-empirical relationships were then developed to determine the tensile strength of structural adhesives from the resonance frequency obtained from the electromechanical impedance technique. This was made possible by correlation between static tensile tests on structural adhesives and the dynamic elastic modulus. These electromechanical impedance–based models were found to perform equally well when compared to the previously developed wave propagation–based models. This study shows the robustness of the electromechanical impedance technique for non-destructively predicting the dynamic elastic modulus and tensile strength of adhesives throughout the curing process.

Progress in the Design of an Improved High-Temperature 1 Percent CrMoV Rotor Steel

1990 ◽  
Vol 112 (1) ◽  
pp. 99-115 ◽  
Author(s):  
R. L. Bodnar ◽  
J. R. Michael ◽  
S. S. Hansen ◽  
R. I. Jaffee
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Room Temperature ◽  
Rupture Strength ◽  
Temper Embrittlement ◽  
Creep Rupture ◽  
Rotor Steel ◽  
Creep Rupture Strength ◽  
Austenitizing Temperature ◽  
Creep Ductility

Silicon-deoxidized, tempered bainitic 1 percent CrMoV steel is currently used extensively for high-temperature steam turbine rotor forgings operating at temperatures up to 565°C due to its excellent creep rupture properties and relative economy. There is impetus to improve the creep rupture strength of this steel while maintaining its current toughness level and vice versa. The excellent creep rupture ductility of the low Si version of this steel allows the use of a higher austenitizing temperature or tensile strength level for improving creep rupture strength without loss in creep ductility or toughness. When the tensile strength of this steel is increased from 785 to 854 MPa, the creep rupture strength exceeds that of the more expensive martensitic 12CrMoVCbN steel currently used for high-temperature rotor applications where additional creep rupture strength is required. The toughness of 1 percent CrMoV steel is improved by lowering the bainite start (Bs) temperature in a “superclean” base composition which is essentially free of Mn, Si, P, S, Sb, As and Sn. The Bs temperature can be lowered through the addition of alloying elements (i.e., C, Ni, Cr, and Mo) and/or increasing the cooling rate from the austenitizing temperature. Using these techniques, the 50 percent FATT can be lowered from approximately 100°C to below room temperature, which provides the opportunity to eliminate the special precautionary procedures currently used in the startup and shutdown of steam turbines. The most promising steels in terms of creep rupture and toughness properties contain 2.5 percent Ni and 0.04 percent Cb (for austenite grain refinement and enhanced tempering resistance). In general, the creep rupture strength of the superclean steels equals or exceeds that of the standard 1 percent CrMoV steel. In addition, the superclean steels have not been found to be susceptible to temper embrittlement, nor do they alter the room temperature fatigue crack propagation characteristics of the standard 1 percent CrMoV steel. These new steels may also find application in combination high-temperature-low-temperature rotors and gas turbine rotors.

scholarly journals Experimental and Numerical Research on Open-Hole Strength and Damage Mechanism of Regularly Arrayed Short Fiber Reinforced Polymer Composite

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1622
Author(s):  
Junfeng Hu ◽  
Xutong Zhang ◽  
Zhou Chen ◽  
Wenkang Guo ◽  
Hang Li ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Damage Mechanism ◽  
Short Fiber ◽  
Numerical Control ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Open Hole ◽  
Continuous Carbon Fiber

Laminates with unidirectionally arrayed chopped strands (UACS) are one of the advanced short fiber reinforced polymer composites (SFRP) with significant application prospect, which greatly improves mechanical properties compared to the traditional SFRP, meanwhile ensuring excellent flowability. In practice, composite laminate with an open hole is one of the typical connective components, and it is necessary to clarify the allowable load and damage tolerance performance of notched structures. In the present study, UACS laminates were fabricated using the continuous carbon fiber reinforced polymer (CFRP) prepreg, on which regularly arrayed bi-angled slits were introduced by a commercial numerical control cutter. The tensile strength and strain distribution around the open hole of the notched UACS laminate were experimentally investigated, while the damage progression near the open hole of the notched UACS laminate was analyzed by the finite element method (FEM). The tensile strength of the notched UACS laminate was measured at 298 MPa, which is about 60% of the strength of the unnotched UACS laminate. The simulation results match well with the experimental results, although there is a little overestimate on strength, by about 5% and 7%, for unnotched and notched UACS laminates, respectively. The final critical failure mode for the notched UACS laminate is mainly dominated by the delamination instead of the fiber breakage in the unnotched UACS laminate.

scholarly journals Anodic and Mechanical Behavior of Carbon Fiber Reinforced Polymer as a Dual-Functional Material in Chloride-Contaminated Concrete

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 222
Author(s):  
Liangliang Wei ◽  
Ji-Hua Zhu ◽  
Zhijun Dong ◽  
Jun Liu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Mechanical Behavior ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Functional Material ◽  
Dual Functional ◽  
Reinforced Polymer ◽  
Chloride Contaminated

Carbon fiber reinforced polymer (CFRP) has been used as a dual-functional material in a hybrid intervention system (ICCP-SS) which integrates the impressed current cathodic protection (ICCP) and structural strengthening (SS). The mechanical behavior of CFRP as an anode has been investigated in some solution environments. However, the anodic and mechanical behavior of CFRP bonded to concrete is unclear. This paper focuses on the anodic and mechanical performance of CFRP bonded to the chloride-contaminated concrete by conducting an electrochemical (EC) test. The method of bonding the CFRP to the concrete and the shape of the steel embedded in the concrete were considered. The current densities of 20 mA/m2 and 100 mA/m2 were applied during 120-day and 310-day EC tests. The electrode potentials and driving voltages were recorded, and the bond interfaces of the CFRP were inspected after EC test. The residual tensile strength and failure modes of the CFRP were analyzed after tensile tests. Finally, the long-term performance of CFRP as a dual-functional material in ICCP-SS system was discussed. Results show that the externally bonding CFRP in ICCP-SS system can not only protect the steel in chloride-contaminated concrete effectively but also maintain 70% of the original tensile strength of CFRP at a charge density of 744 A·h/m2. The expected service period of CFRP as a dual-functional material bonded to the chloride-contaminated concrete was determined to be more than 42.5 years.

scholarly journals Tensile Behavior of Carbon Fiber-Reinforced Polymer Composites Incorporating Nanomaterials after Exposure to Elevated Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Gia Toai Truong ◽  
Hai Van Tran ◽  
Kyoung-Kyu Choi
Keyword(s):  
Tensile Strength ◽  
Elevated Temperatures ◽  
Tensile Behavior ◽  
Ultimate Strain ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Multiwalled Carbon ◽  
Maximum Tensile Strength ◽  
Reinforced Polymer ◽  
Cfrp Composites

This study experimentally examined the effect of nanomaterial on the tensile behavior of carbon fiber-reinforced polymer (CFRP) composites. Multiwalled carbon nanotubes (MWCNT), graphene nanoplatelets (GnPs), and short multiwalled carbon nanotubes functionalized COOH (S-MWCNT-COOH) with 1% by weight were used as the primary test parameters. In the present test, S-MWCNT-COOH was more effective than the others in improving the maximum tensile strength, ultimate strain, and toughness of the CFRP composites. The use of S-MWCNT-COOH increased the maximum tensile strength, ultimate strain, and toughness of the CFRP composites by 20.7, 45.7, and 73.8%, respectively. In addition, tensile tests were carried out for CFRP composites with S-MWCNT-COOH after subjection to elevated temperatures ranging from 50 to 200°C. The test results showed that the tensile strength, ultimate strain, and toughness were significantly reduced with increasing temperature. At a temperature level of 100°C, the reduction of the maximum tensile strength, ultimate strain, and toughness was 36.5, 37.1, and 60.0%, respectively. However, for the specimens subjected to the elevated temperatures ranging from 100 to 200°C, the tensile behavioral properties were constantly maintained. Finally, various analytical models were applied to predict the tensile strength of the CFRP composites with S-MWCNT-COOH. By using the calibrated parameters, the tensile strengths predicted by the models showed good agreement with the experimental results.

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