Length effect on the performance of lumber in tension

A study was conducted to evaluate the effect of gauge length on the short-term performance of visually graded Select Structural and No. 2 kiln-dried nominal 38 × 89 mm spruce-pine-fir lumber in tension parallel-to-grain. The short-term tensile strength properties of three groups of lumber, matched for modulus of elasticity and having gauge lengths of 2642, 3683, 4877 mm, were obtained from test results where the effect of gauge length was isolated from the effect of grade. The performance of the lumber was evaluated by first-order second-moment reliability analyses. In the analyses, the lumber was treated as single tension members under uniform tensile stress along the member length, undergoing snow load conditions at various locations in Canada. The results indicate that the performance factor for Select Structural spruce-pine-fir lumber in tension parallel-to-grain should be multiplied by a factor of 0.92 to adjust for doubling the length from 2500 to 5000 mm to achieve a common reliability index of 3.0. The effect of doubling the length from 2500 to 5000 mm on the performance of No. 2 spruce-pine-fir lumber appears to be negligible. Key words: length effect, tensile strength, lumber, performance factor, reliability index.

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Performance of SiO2-impregnated flax fibre reinforced polymers under wet dry and freeze thaw cycles

Journal of Composite Materials ◽

10.1177/0021998320946811 ◽

2020 ◽

Vol 55 (2) ◽

pp. 251-263

Author(s):

Kenneth Mak ◽

Amir Fam

Keyword(s):

Tensile Strength ◽

Mechanical Damage ◽

Tensile Modulus ◽

Flax Fibre ◽

Short Term ◽

Freeze Thaw ◽

Post Exposure ◽

Flax Fibres ◽

Pull Out ◽

Term Performance

Flax fibres are of growing interest as a reinforcing fibre; however, they are susceptible to moisture and have demonstrated poor bond to conventional hydrophobic resins. Although there are multiple approaches to address these issues, research has heavily focused on their short-term performance. In this research program, the performance of flax fibre reinforced polymer (FFRP), manufactured using SiO2-impregnated flax fibre, is assessed for its short-term performance as well as its long-term performance when exposed to wet-dry (WD) and freeze-thaw (FT) cycles. Treated FFRP showed improved bond between the fibre and resin as well as resistance to fibre pull-out. It exhibited a tensile strength of 144 ± 15 MPa and a tensile modulus of 8.6 ± 0.35 GPa. When exposed to WD cycles, delamination between the fibre and resin were observed. The onset of statistically significant mechanical damage occurred after four WD cycles, with a final 3% reduction in strength and a 6% reduction in modulus post-exposure. When exposed to FT cycles, FFRP experienced cracking within the fibre, as well as delamination at the interface. The onset of statistically significant mechanical damage occurred after 50 FT cycles, which manifested as a final 5% reduction in tensile strength and 10% reduction in tensile modulus post-exposure. Regardless of treatment, FFRP demonstrated the same damage mechanisms as untreated variants.

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Increased dryness after pressing and wet web strength by utilizing foam application technology

TAPPI Journal ◽

10.32964/tj15.11.731 ◽

2016 ◽

Vol 15 (11) ◽

pp. 731-738 ◽

Cited By ~ 1

Author(s):

KARITA KINNUNEN-RAUDASKOSKI ◽

KRISTIAN SALMINEN ◽

JANI LEHMONEN ◽

TUOMO HJELT

Keyword(s):

Tensile Strength ◽

Guar Gum ◽

Paper Industry ◽

Reference Sample ◽

Strength Properties ◽

Cellulose Microfibrils ◽

Application Technology ◽

Ethylene Vinyl Alcohol ◽

Wet Pressing ◽

Web Strength

Production cost savings by lowering basis weight has been a trend in papermaking. The strategy has been to decrease the amount of softwood kraft pulp and increase use of fillers and recycled fibers. These changes have a tendency to lower strength properties of both the wet and dry web. To compensate for the strength loss in the paper, a greater quantity of strength additives is often required, either dosed at the wet end or applied to the wet web by spray. In this pilot-scale study, it was shown how strength additives can be effectively applied with foam-based application technology. The technology can simultaneously increase dryness after wet pressing and enhance dry and wet web strength properties. Foam application of polyvinyl alcohol (PVA), ethylene vinyl alcohol (EVOH), carboxymethyl cellulose (CMC), guar gum, starch, and cellulose microfibrils (CMF) increased web dryness after wet pressing up to 5.2%-units compared to the reference sample. The enhanced dewatering with starch, guar gum, and CMF was detected with a bulk increase. Additionally, a significant increase in z-directional tensile strength of dry web and and in-plane tensile strength properties of wet web was obtained. Based on the results, foam application technology can be a very useful technology for several applications in the paper industry.

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COMPARATIVE STUDY OF TENSILE STRENGTH PROPERTIES OF FIBER REINFORCED COMPOSITE LAMINATES WITH DIFFERENT ORIENTATIONS OF FIBERS

i-manager’s Journal on Mechanical Engineering ◽

10.26634/jme.8.1.13823 ◽

2018 ◽

Vol 8 (1) ◽

pp. 26

Author(s):

SAIDULU H ◽

HUSSAIN M. MANZOOR ◽

◽

Keyword(s):

Tensile Strength ◽

Comparative Study ◽

Composite Laminates ◽

Strength Properties ◽

Fiber Reinforced ◽

Fiber Reinforced Composite ◽

Reinforced Composite

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Faculty Opinions recommendation of Short-term performance of the transcatheter Melody valve in high-pressure hemodynamic environments in the pulmonary and systemic circulations.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.714247958.789752860 ◽

2012 ◽

Author(s):

Larry Latson ◽

Athar Qureshi

Keyword(s):

High Pressure ◽

Short Term ◽

Melody Valve ◽

Term Performance

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Short-Term and Long-Term Performance Persistence: A Comparative Study of UK Investment Trusts

SSRN Electronic Journal ◽

10.2139/ssrn.3266396 ◽

2018 ◽

Author(s):

Michel Guirguis

Keyword(s):

Comparative Study ◽

Performance Persistence ◽

Short Term ◽

Investment Trusts ◽

Long Term Performance ◽

Term Performance

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Evaluation of the Impact of Organic Fillers on Selected Properties of Organosilicon Polymer

Polymers ◽

10.3390/polym13071103 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1103

Author(s):

Sara Sarraj ◽

Małgorzata Szymiczek ◽

Tomasz Machoczek ◽

Maciej Mrówka

Keyword(s):

Tensile Strength ◽

Natural Fiber ◽

Accelerated Aging ◽

Strength Properties ◽

Visual Observation ◽

Walnut Shell ◽

Pistachio Shell ◽

Thermoplastic Matrix ◽

Static Tensile ◽

The Impact

Eco-friendly composites are proposed to substitute commonly available polymers. Currently, wood–plastic composites and natural fiber-reinforced composites are gaining growing recognition in the industry, being mostly on the thermoplastic matrix. However, little data are available about the possibility of producing biocomposites on a silicone matrix. This study focused on assessing selected organic fillers’ impact (ground coffee waste (GCW), walnut shell (WS), brewers’ spent grains (BSG), pistachio shell (PS), and chestnut (CH)) on the physicochemical and mechanical properties of silicone-based materials. Density, hardness, rebound resilience, and static tensile strength of the obtained composites were tested, as well as the effect of accelerated aging under artificial seawater conditions. The results revealed changes in the material’s properties (minimal density changes, hardness variation, overall decreasing resilience, and decreased tensile strength properties). The aging test revealed certain bioactivities of the obtained composites. The degree of material degradation was assessed on the basis of the strength characteristics and visual observation. The investigation carried out indicated the impact of the filler’s type, chemical composition, and grain size on the obtained materials’ properties and shed light on the possibility of acquiring ecological silicone-based materials.

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Absorption and Strength Properties of Short Carbon Fiber Reinforced Mortar Composite

Buildings ◽

10.3390/buildings11070300 ◽

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.

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Mechanical properties of low-density paper

Nordic Pulp & Paper Research Journal ◽

10.1515/npprj-2019-0052 ◽

2020 ◽

Vol 35 (1) ◽

pp. 61-70

Author(s):

Na Young Park ◽

Young Chan Ko ◽

Lili Melani ◽

Hyoung Jin Kim

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Structural Change ◽

Tensile Testing ◽

Tensile Modulus ◽

Gauge Length ◽

Efficiency Factor ◽

Low Density ◽

Tensile Stiffness ◽

Lower Tensile Strength

AbstractFor the mechanical properties of paper, tensile testing has been widely used. Among the tensile properties, the tensile stiffness has been used to determine the softness of low-density paper. The lower tensile stiffness, the greater softness of paper. Because the elastic region may not be clearly defined in a load-elongation curve, it is suggested to use the tensile modulus which is defined as the slope between the two points in the curve. The two points which provide the best correlation with subjective softness evaluation should be selected. Low-density paper has a much lower tensile strength, but much larger elongation at the break. It undergoes a continuous structural change during mechanical testing. The degree of the structural change should depend on tensile conditions such as the sample size, the gauge length, and the rate of elongation. For low-density paper, the tensile modulus and the tensile strength should be independent of each other. The structure efficiency factor (SEF) is defined as a ratio of the tensile strength to the tensile modulus and it may be used a guideline in developing superior low-density paper products.

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Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽

10.3390/met11040548 ◽

2021 ◽

Vol 11 (4) ◽

pp. 548 ◽

Cited By ~ 1

Author(s):

Leonid Agureev ◽

Valeriy Kostikov ◽

Zhanna Eremeeva ◽

Svetlana Savushkina ◽

Boris Ivanov ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Elastic Modulus ◽

Strength Properties ◽

Alumina Nanoparticles ◽

Metal Powders ◽

Wide Range ◽

The Matrix ◽

Spark Plasma ◽

Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

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