scholarly journals Influence of Thickness on Water Absorption and Tensile Strength of BFRP Laminates in Water or Alkaline Solution and a Thickness-Dependent Accelerated Ageing Method for BFRP Laminates

2020 ◽  
Vol 10 (10) ◽  
pp. 3618
Author(s):  
Yanlei Wang ◽  
Wanxin Zhu ◽  
Xue Zhang ◽  
Gaochuang Cai ◽  
Baolin Wan
Keyword(s):  
Tensile Strength ◽  
Water Absorption ◽  
Tensile Properties ◽  
Alkaline Solution ◽  
Ageing Time ◽  
Accelerated Ageing ◽  
Specimen Thickness ◽  
Test Results ◽  
Strength Retention

This paper first presented an experimental study on water absorption and tensile properties of basalt fiber-reinforced polymer (BFRP) laminates with different specimen thicknesses (i.e., 1, 2, and 4 mm) subjected to 60 °C deionized water or alkaline solution for an ageing time up to 180 days. The degradation mechanism of BFRP laminates in solution immersion was also explored combined with micro-morphology analysis by scanning electronic microscopy (SEM). The test results indicated that the water absorption and tensile properties of BFRP laminates were dramatically influenced by specimen thickness. When the BFRP laminates with different thicknesses were immersed in the solution for the same ageing time, the water absorption of the specimens decreased firstly before reaching their peak water absorption and then increased in the later stage with the increase of specimen thickness, while the tensile strength retention sustaining increased as specimen thickness increased. The reason is that the thinner the specimen, the more severe the degradation. In this study, a new accelerated ageing method was proposed to predict the long-term water absorption and tensile strength of BFRP laminates. The accelerated factor of the proposed method was determined based on the specimen thickness. The proposed method was verified by test results with a good accuracy, indicating that the method could be used to predict long-term water absorption and tensile strength retention of BFRP laminates by considering specimen thickness in accelerating tests.

scholarly journals Absorption and Strength Properties of Short Carbon Fiber Reinforced Mortar Composite

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 300
Author(s):  
Md. Safiuddin ◽  
George Abdel-Sayed ◽  
Nataliya Hearn
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Absorption ◽  
Carbon Fibers ◽  
Strength Properties ◽  
Fiber Content ◽  
Test Results ◽  
Air Content ◽  
Entrapped Air ◽  
Short Carbon

This paper presents the water absorption and strength properties of short carbon fiber reinforced mortar (CFRM) composite. Four CFRM composites with 1%, 2%, 3%, and 4% short pitch-based carbon fibers were produced in this study. Normal Portland cement mortar (NCPM) was also prepared for use as the control mortar. The freshly mixed mortar composites were tested for workability, wet density, and entrapped air content. In addition, the hardened mortar composites were examined for compressive strength, splitting tensile strength, flexural strength, and water absorption at the ages of 7 and 28 days. The effects of different carbon fiber contents on the tested properties were observed. Test results showed that the incorporation of carbon fibers decreased the workability and wet density, but increased the entrapped air content in mortar composite. Most interestingly, the compressive strength of CFRM composite increased up to 3% carbon fiber content and then it declined significantly for 4% fiber content, depending on the workability and compaction of the mortar. In contrast, the splitting tensile strength and flexural strength of the CFRM composite increased for all fiber contents due to the greater cracking resistance and improved bond strength of the carbon fibers in the mortar. The presence of short pitch-based carbon fibers significantly strengthened the mortar by bridging the microcracks, resisting the propagation of these minute cracks, and impeding the growth of macrocracks. Furthermore, the water absorption of CFRM composite decreased up to 3% carbon fiber content and then it increased substantially for 4% fiber content, depending on the entrapped air content of the mortar. The overall test results suggest that the mortar with 3% carbon fibers is the optimum CFRM composite based on the tested properties.

Effects of Accelerated Aging Period of Time at 180°C on Tensile Property of Plain Woven Fabric/Epoxy Resin Laminated Composites

2012 ◽  
Vol 182-183 ◽  
pp. 76-79 ◽  
Author(s):  
Lei Lei Song ◽  
Quan Rong Liu ◽  
Jia Lu Li
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Laminated Composites ◽  
Accelerated Aging ◽  
Woven Fabric ◽  
Accelerated Ageing ◽  
Time Intervals ◽  
Composite Samples

In this paper, carbon fiber reinforced resin matrix composites were produced by stacking eight pieces of carbon fiber woven plain fabric and subjected to accelerated ageing. Accelerated ageing was carried out in oven at 180°C for three different time intervals (60 hours, 120 hours and 180 hours). The influence of different ageing time intervals at 180°C on tensile properties of laminated composites was examined, compared with the composites without aging. The appearance and damage forms of these laminated composites were investigated. The results revealed that the tensile strength of the laminates declined significantly after long term accelerated aging at 180°C. The average tensile strengths of composite samples aged 60 hours, 120 hours, and 180 hours period of time at 180°C are 80.36%, 79.82%, 76.57% of average tensile strength of composite samples without aging, respectively. The high temperature accelerated aging makes the resin macromolecular structure in the composites changed, and then the adhesive force between fiber bundles and resin declines rapidly which result in the tensile strength of composites aged decrease. This research provides a useful reference for long term durability of laminated/epoxy resin composites.

Temperature effects on ageing properties and diffusivity of a HDPE GM in landfill

2021 ◽  
pp. 0734242X2110570
Author(s):  
Shengwei Wang ◽  
Tao Guo ◽  
Huan Tian ◽  
Zhigang Li ◽  
Kang Fei
Keyword(s):  
Diffusion Coefficient ◽  
Tensile Properties ◽  
Ageing Time ◽  
Melt Flow Index ◽  
Engineering Properties ◽  
Flow Index ◽  
Test Results ◽  
Oxidation Induction Time ◽  
Degradation Rates ◽  
And Migration

High-density polyethylene (HDPE) geomembranes (GMs) play a crucial role in preventing the leakage and migration of pollutants. GM service life and ageing properties are the main concerns for the choice of materials. However, it is not clear how the mechanical properties and anti-fouling performance of geomembranes change with ageing time. To solve this problem, a HDPE GM was selected for testing under exposed air condition. The tests included oxidation induction time (OIT), melt flow index (MFI), tensile properties and diffusivity under four temperature conditions for 1½ years. The test results showed that the GM has higher OIT degradation rates. Stage I – depletion of antioxidants occurred at only 10 years for the GM, which was approximately 1/4 that of the GM-GSE. The GM engineering properties index showed the same changes as those of the GM-GSE. However, MI rapidly decreased with the incubation time. The molecular weight degradation of the GM was approximately 57% and far greater than that of GM-GSE after 15 months, but the tensile properties of the two GMs showed little change. The diffusion coefficient Di of GM increases gradually with the increase of temperature in methane and trichloromethane. Under the same conditions, the diffusion coefficient Di of the GM in methane is significantly higher than that in trichloromethane, indicating that the GM has better barrier to trichloromethane.

TIMETAL 6-2-4-2

Alloy Digest ◽  
2007 ◽  
Vol 56 (6) ◽  
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Creep Strength ◽  
Temperature Stability ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Temperature Performance

Abstract Timetal 6-2-4-2 has a combination of tensile strength, creep strength, toughness, and high-temperature stability for long-term application at temperatures up to 538 deg C (1000 deg F). This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: TI-140. Producer or source: Timet.

Microstructure and Tensile Properties of a 1.25Cr-0.5Mo Main Steam Pipe After Long-Term Service

2018 ◽  
Author(s):  
Bin Yang ◽  
Wen-Chun Jiang ◽  
Wen-Qi Sun ◽  
Yan-Ling Zhao ◽  
Wei-Ya Zhang
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Tensile Properties ◽  
Yield Stress ◽  
Tensile Deformation ◽  
High Yield ◽  
Micro Hardness ◽  
Steam Pipe ◽  
Main Steam

Metallographic tests, micro-hardness tests and tensile tests were conducted for a 1.25Cr-0.5Mo main steam pipe weldment served for more than 26 years. The results were compared with those for virgin material. Microstructural evolution of 1.25Cr-0.5Mo base metal was investigated. Degradation in micro-hardness and tensile properties were also studied. In addition, the tensile properties of subzones in the ex-service weldment were characterized by using miniature specimens. The results show that obvious microstructural changes including carbide coarsening, increasing inter lamella spacing and grain boundary precipitates take place after long-term service. Degradation in micro-hardness is not obvious. However, the effects of long term service on tensile deformation behavior, ultimate tensile strength and yield stress are remarkable. Based on the yield stress of micro-specimens, the order of different subzones is: WM > HAZ > BM, which is consistent with the order of different subzones based on micro-hardness. However, the ultimate tensile strength and fracture strain of HAZ are lower than BM. Brittle failures can happen more easily for HAZ due to its high yield ratio.

Exploring seed longevity of UK native trees: implications for ex situ conservation

2020 ◽  
Vol 30 (2) ◽  
pp. 101-111
Author(s):  
Rachael M. Davies ◽  
Alice R. Hudson ◽  
John B. Dickie ◽  
Charlotte Cook ◽  
Tom O'Hara ◽  
...  
Keyword(s):  
Seed Bank ◽  
Ageing Time ◽  
Seed Storage ◽  
Woody Species ◽  
Ex Situ ◽  
Accelerated Ageing ◽  
Actual Performance ◽  
Long Term Storage ◽  
Multiple Samples

AbstractUK trees require increased conservation efforts due to sparse and fragmented populations. Ex situ conservation, including seed banking, can be used to better manage these issues. We conducted accelerated ageing tests on seeds of 22 UK native woody species, in order to assess their likely longevity and optimize their conservation in a seed bank. Germination at four ageing time points was determined to construct survival curves, and it was concluded that multiple samples within a species showed comparable responses for most species tested, except for Fraxinus excelsior. Of all species studied, one could be classified as very short-lived, four as short-lived and 17 as medium, with none exceeding the medium category. The most important finding of this manuscript is that although some taxonomic trends were observed, the results indicate the need for caution when making broad conclusions on potential seed storage life at a species, genus or family level. Longevity predictions were compared to actual performance of older collections held in long-term storage at the Millennium Seed Bank, Kew. Although most collections remain high in viability in storage after more than 20 years, for short-lived species at least, there is some indication that accelerated ageing predicts longevity in seed bank conditions. For species with reduced potential longevity, such as Fagus sylvatica and Ulmus glabra, additional storage options are recommended for long-term gene banking.

The Influence of AlkaliTreatment and Compatibilizer Addition on the Tensile Properties and Water Absorption Behavior of Polypropylene/Kenaf Fiber Composites

2012 ◽  
Vol 626 ◽  
pp. 449-453 ◽  
Author(s):  
Razaina Mat Taib ◽  
Nurul Mujahidah Ahmad Khairuddin ◽  
Zainal Arifin Mohd Ishak
Keyword(s):  
Tensile Strength ◽  
Maleic Anhydride ◽  
Water Absorption ◽  
Tensile Properties ◽  
Room Temperature ◽  
Water Resistance ◽  
Alkali Treatment ◽  
Tensile Modulus ◽  
Fiber Composites ◽  
Kenaf Fiber

Composites of polypropylene (PP) and kenaf fiber (KF) were immersed in water at room temperature. The fiber was treated with alkaline solution. A compatibilizer, maleic anhydride-grafted polypropylene (MAPP) was added in some composite formulations. Composite with alkali treated fibers (KFA) showed similar tensile strength but lower tensile modulus than the composite with untreated fiber, KF. Addition of MAPP was crucial to improve the tensile properties and water resistance of either PP/KF or PP/KFA composites. Alkali treatment adversely affected the water absorption behavior of PP/KF composite.

Effects of UV Irradiation on the Molecular Structure and Tensile Properties of Nucleated Polypropylene

2014 ◽  
Vol 905 ◽  
pp. 82-87 ◽  
Author(s):  
You Ji Tao ◽  
Gan Xin Jie ◽  
Xiao Dong Zhang ◽  
Li Fen Hu ◽  
Jian Peng ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Uv Irradiation ◽  
Irradiation Time ◽  
Relative Content ◽  
Carbonyl Index ◽  
Relationship Of ◽  
The Relationship ◽  
Strength Retention

A sorbitolum compound and an aryl amide compound were applied to prepare α-nucleated PP (α-PP) and β-nucleated PP (β-PP), respectively. Effects of UV irradiation on the molecular structure and tensile properties of pure PP, α-PP and β-PP were investigated. The relationship of tensile strength with carbonyl index was discussed. The change of relative content of β-modification in β-PP during photodegradation was examined by WAXD. The carbonyl index calculated from FTIR spectra arranged as α-PP > PP > β-PP, however, the tensile strength retention at the UV irradiation time of 792h arranged as PP > β-PP > α-PP. The relative content of β-crystal nearly unchanged during the photodegradation.

Tensile Properties of a Cast TiAl Alloy with Directional Lamellar Microstructures

2013 ◽  
Vol 652-654 ◽  
pp. 1063-1066
Author(s):  
Sheng Li ◽  
Chun Lei Zhu ◽  
Rui Cao ◽  
Ji Zhang
Keyword(s):  
Tensile Strength ◽  
Room Temperature ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Critical Value ◽  
Test Results ◽  
Tensile Fractures ◽  
Strength Retention ◽  
Strength And Ductility ◽  
Surface Observations

A cast TiAl alloy with directional γ-TiAl/α2-Ti3Al lamellar microstructure showed excellent strength retention at high temperatures and distinguished ambient ductility level as well. But both the ductility and strength at room temperature exhibited somewhat undulation. According to the microstructure and fracture surface observations, the negative diversification of the test results is attributed to the presence of mis-oriented lamellar colonies. The tilted lamellar colonies larger than a critical value can trigger the tensile fractures and therefore diminish the tensile strength and ductility significantly.

The Evolution of Heat Treatment on the Tensile Properties of Na-Modified Al-Mg2Si In Situ Composite

2011 ◽  
Vol 311-313 ◽  
pp. 283-286 ◽  
Author(s):  
R. Khorshidi ◽  
A. Honarbakhsh Raouf ◽  
M. Emamy ◽  
H.R. Jafari Nodooshan
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Quality Index ◽  
Solution Treatment ◽  
Test Results ◽  
Temperature Level ◽  
In Situ Composite ◽  
Different Temperatures

The effect of different solution temperatures has been investigated on the tensile properties of Na-modified Al-Mg2Si in situ composite specimens which were subjected to solutionizing at different temperatures of 480 °C, 500 °C and 520 °C for holding time of 4 h followed by quenching. Tensile test results indicated that elongation value gradually increases upon solution treatment whereas ultimate tensile strength (UTS) reduces. The results of solution treatment also showed that the highest quality index is achieved in 500 °C (354 MPa) and so it is revealed optimum solutionizing temperature level (500 °C) for improving tensile properties.

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