scholarly journals Yellow Pine Small Clear Flexural Properties across Five Decades

2021 ◽  
Vol 71 (3) ◽  
pp. 233-239
Author(s):  
Frederico José Nistal França ◽  
Rubin Shmulsky ◽  
J. Tedrick Ratcliff ◽  
Benjamin Farber ◽  
C. Adam Senalik ◽  
...  
Keyword(s):  
Forest Management ◽  
Bending Strength ◽  
Basic Density ◽  
Flexural Properties ◽  
Southern Pine ◽  
Bending Properties ◽  
Three Samples ◽  
Controllable Factors ◽  
Yellow Pine ◽  
Over Time

Abstract When discussing structural southern yellow pine lumber, questions frequently are asked regarding changes over time. This is a significant area of discussion given that structural lumber properties (i.e., design values) were changed around 2012. Climate change, forest management, genetics, processing, and others are listed among the many possible contributing factors. Of interest are these questions: (1) Are changes in bending properties permanent at some fundamental level, or are they somewhat dynamic and responsive to controllable factors? (2) To what degree have the basic southern pine wood mechanical properties changed over time? Related thereto, this research examines the bending properties of small clear pine specimens from three samples. Sample 1 was pulled from a production-weighted sample of in-grade parent lumber. Sample 2 was pulled from commercially available molding and millwork. Sample 3 was pulled from data from the U.S. Department of Agriculture Forestry Products Laboratory from the early to mid-1960s. The flexural properties of small clear specimens among the three samples showed some statistically significant differences. However, there was no clear trend regarding these differences. These results appear to support the notion that while the variability of pine's flexural properties is significant and that while many changes in forest management and production have occurred over the past five decades, the basic density and bending strength of clear southern pine appear generally stable over time.

Correlations between Grain Angle Meter Readings and Bending Properties of Mill-Run Southern Pine Lumber

2020 ◽  
Vol 70 (3) ◽  
pp. 275-278
Author(s):  
Guangmei Cao Anderson ◽  
Frank C. Owens ◽  
Frederico Franca ◽  
Robert J. Ross ◽  
Rubin Shmulsky
Keyword(s):  
Bending Strength ◽  
Modulus Of Rupture ◽  
Supplementary Data ◽  
Southern Pine ◽  
Bending Properties ◽  
Grain Angle ◽  
Technical Modifications ◽  
Pine Lumber ◽  
Pinus Spp ◽  
Southern Pine Lumber

Abstract Metriguard's grain angle meter (Model 511) measures grain angle in wood by assessing permittivity. This study evaluates the correlations between grain angle meter readings and bending properties of 1,400 kiln-dried 2 by 4 specimens of southern pine (Pinus spp.) lumber and considers its utility for providing supplementary data for predicting the strength of lumber. The results showed that in mill-run lumber, the correlation between grain angle and modulus of rupture (MOR) was −0.420. In addition, in graded lumber, the correlation between grain angle and MOR got progressively stronger as the grade went down. With a few technical modifications, applying this device in a mill production setting could prove useful for supplementing other nondestructive methods for assessing bending strength in lumber.

Interrelationships of specific gravity, stiffness, and strength of yellow pine across five decades

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3815-3826
Author(s):  
Frederico Jose Nistal França ◽  
Rubin Shmulsky ◽  
Tedrick Ratcliff ◽  
Benjamin Farber ◽  
C. Adam Senalik ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Modulus Of Rupture ◽  
Resource Monitoring ◽  
Non Destructive Evaluation ◽  
Three Samples ◽  
Yellow Pine ◽  
The Relationship ◽  
Non Destructive ◽  
Insight Into ◽  
Over Time

The interrelationships among specific gravity (SG), modulus of elasticity (MOE), and strength (modulus of rupture, MOR) are largely the foundational basis for non-destructive evaluation and testing. Resource monitoring and commercial structural lumber production often rely upon such non-destructive evaluation to predict the bending and/or tension strength of individual members. These technologies require routine calibration. In addition, it is important to know the extent to which a given resource may change over time. To that end, this study investigated the relationship among SG, MOE, and MOR of small clear specimens from three samples taken across an approximate 50-year period; 1965 to 2018. Coefficients of determination among these variables are presented along with the prediction equations. These findings can be used to gain insight into the reliability and stability of these relationships over time.

Research on Damage and Bending Properties of AZ31 Magnesium Alloy

2012 ◽  
Vol 184-185 ◽  
pp. 1163-1166
Author(s):  
Xi An Xie ◽  
Gao Feng Quan
Keyword(s):  
Magnesium Alloy ◽  
Applied Load ◽  
Bending Strength ◽  
Az31 Magnesium Alloy ◽  
Bending Test ◽  
Bending Properties ◽  
Four Point Bending ◽  
Heat Treated ◽  
Four Point Bending Test ◽  
Initial Cracks

Through the four-point bending test of lath-shaped heat treated AZ31 magnesium alloy, the bending properties and damage characteristics were explored. The results show that the optimal bending strength of the magnesium alloy were 355.1MPa and 259.2MPa for extruded and cast samples, respectively, after corresponding heat treatment with 350°C, 90min and 400°C, 30min. The initial cracks both occurred at the loading point after applied load exceeded the yield limit of AZ31 magnesium alloy. Surface bump, cracks and other damage morphology accompanied by a large number of twinning organizations were found on the surface of the samples.

scholarly journals Fabrication of Silk Resin with High Bending Properties by Hot-Pressing and Subsequent Hot-Rolling

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2716
Author(s):  
Hoang Anh Tuan ◽  
Shinji Hirai ◽  
Shota Inoue ◽  
Alharbi A. H. Mohammed ◽  
Shota Akioka ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Hot Pressing ◽  
Bending Strength ◽  
Decomposition Temperature ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Bending Properties ◽  
X Ray ◽  
Bombyx Mori Silk ◽  
Increased Strength

This research reports the processability and mechanical properties of silk resins prepared by hot-pressing followed by hot-rolling and then analyzes their thermal and structural properties. The results show that regenerated silk (RS) resins are better suited for hot-rolling than Eri and Bombyx mori silk resins (untreated silk). When hot-rolling at 160 °C with a 50% of reduction ratio, maximum bending strength and Young’s modulus of RS resin reaches 192 MPa and 10.2 GPa, respectively, after pretreatment by immersion in 40 vol% ethanol, and 229 MPa and 12.5 GPa, respectively, after pretreatment by immersion in boiling water. Increased strength of the material is attributed to the increased content of aggregated strands and intramolecular linking of β sheets (attenuated total reflectance Fourier-transform infrared spectroscopy) and higher crystallinity (X-ray diffraction analysis). After hot-pressing and hot-rolling, RS resins have a stable decomposition temperature (297 °C).

scholarly journals An experimental investigation for the temperature effect on the bending properties of multiaxial warp-knitted composite

2020 ◽  
Vol 15 ◽  
pp. 155892502091558
Author(s):  
Xiaoping Gao ◽  
Xiaori Yang ◽  
Xianyan Wu ◽  
Pibo Ma
Keyword(s):  
Bending Strength ◽  
Bending Properties ◽  
Sem Images ◽  
Nonlinear Fitting ◽  
Bending Modulus ◽  
Ultimate Bending Strength ◽  
Different Temperatures ◽  
Bending Behavior ◽  
Fracture Morphologies ◽  
Properties Of Composites

An experimental study of bending properties of composites reinforced with triaxial and quadaxial warp-knitted glass fabrics was carried out in the 0°, 45°, and 90° directions at −30°C, 0°C, 20°C, and 40°C, respectively. The relationships between the stress–strain curves, bending strength, bending modulus, and temperature were obtained. The failure mechanisms at different temperatures were also analyzed based on the fracture morphologies and scanning electron microscope (SEM) images. The results indicated that the bending properties decrease slightly with the increase in temperature from −30°C to 20°C and decrease dramatically from 20°C to 40°C. The ultimate bending strength of triaxial and quadaxial warp-knitted composites decreases approximately 31.34% and 34.29%, respectively. In particular, the relationships between bending strength and temperature were also obtained by nonlinear fitting with the experimental data, which could be used to predict the bending behavior at different temperatures.

Research on the Bending Properties of the Bamboo-Wood Container Flooring

2013 ◽  
Vol 744 ◽  
pp. 366-369
Author(s):  
Juan Wei ◽  
Dan Zeng ◽  
Ming Jie Guan
Keyword(s):  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Accelerated Aging ◽  
Modulus Of Rupture ◽  
Bending Properties ◽  
Before And After ◽  
Aging Performance

In this paper, the bending properties of bamboo-wood container flooring and bamboo curtain-OSB container flooring were tested and the six-cycle artificial accelerated aging method of ASTM D1037 was conducted to evaluate the aging performance of two kinds of bamboo-wood container floorings. The modulus of rupture (MOR) and modulus of elasticity (MOE) were tested in the longitudinal and transverse directions before and after aging. The results showed that both the bending strength and MOE decreased after aging. The retention ratios of MOR of the bamboo-wood container flooring and bamboo curtain-OSB container flooring were respectively 43.5%, 72.0%, and the retention ratios of MOE were 54.6%, 76.3%. In general, the effect of aging on the bamboo-wood container flooring was larger than that on the bamboo curtain-OSB container flooring.

scholarly journals Characterization of Algerian kaolins for utilization as a raw material in electrical insulators

Cerâmica ◽  
2019 ◽  
Vol 65 (374) ◽  
pp. 267-273
Author(s):  
M. Laraba
Keyword(s):  
Bending Strength ◽  
Dielectric Strength ◽  
Raw Material ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
Electrical Insulator ◽  
X Ray ◽  
Three Samples ◽  
Porcelain Insulators

Abstract The aim of this investigation was to characterize three samples of kaolin (DD1, DD2 and DD3) collected from Djebel Debbagh deposit (East of Algeria) to be used in electrical porcelain insulators. Grain-size analysis, X-ray fluorescence, X-ray diffraction, scanning electron microscopy and thermal analysis (TG-DTA) were performed. Each sample was mixed with feldspar and silica to obtain three porcelain formulations. The obtained results indicated that the three kaolins were composed by kaolinite and halloysite with variable contents of MnO and Fe2O3 as associated impurities. It was found that the DD1 was the appropriate kaolin as raw material for making the high-voltage electrical insulator which had the highest electrical and mechanical properties (dielectric strength, bending strength and bulk density), while DD2 and DD3 were less suitable due to their lower properties caused by the presence of impurities which must be removed.

Interfacial properties of aramid/basalt fiber reinforced hybrid composites by addition of Halloysite nanotube

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940031 ◽  
Author(s):  
Jin-Woo Lee ◽  
Tianyu Yu ◽  
Soo-Jeong Park ◽  
Yun-Hae Kim
Keyword(s):  
Fracture Toughness ◽  
Epoxy Resin ◽  
Hybrid Composite ◽  
Bending Strength ◽  
Hybrid Composites ◽  
Basalt Fiber ◽  
Interfacial Properties ◽  
Bending Properties ◽  
Halloysite Nanotube ◽  
Ultrasound Device

We investigated the effect of Halloysite nanotube (HNT) addition on the interfacial and bending properties of hybrid composites. Test specimens were prepared using a vacuum bag method, which is manufactured by using an autoclave device. Ultrasound device was used to uniformly disperse HNT nanoparticles into the epoxy. Amount of the nanoparticles was determined by the weight of the epoxy resin. The Fracture toughness, ILSS and bending strength of Aramid/Basalt fiber hybrid composite specimens were decreased by more than certain amount of HNT. This phenomenon is presumably due to aggregation of HNT.

Bending Properties and Failure Mechanisms of Tapered 3D Braided Composites

2011 ◽  
Vol 332-334 ◽  
pp. 1468-1471 ◽  
Author(s):  
Can Can Cheng ◽  
Zhao Lin Liu ◽  
Li Fang Liu ◽  
Jian Yong Yu
Keyword(s):  
Failure Modes ◽  
Bending Strength ◽  
Failure Mechanisms ◽  
Reduction Technique ◽  
Braided Composites ◽  
Bending Properties ◽  
Bending Tests ◽  
Three Point Bending ◽  
Bending Modulus ◽  
3D Braided Composites

Tapered 3D braided composites are prepared by column yarn-reduction technique, unit yarn-reduction technique and cutting, respectively. Bending properties in the tapered regions of the composites are obtained by three-point bending tests, and SEM photographs of the fracture surfaces are observed to analyze the failure mechanisms. Results show that bending modulus and bending strength of the yarn-reduction composites are significantly higher than those of the cut composites, and the unit yarn-reduction composites are slightly stronger than the column yarn-reduction composites. The saw-tooth propagation of matrix crackings and interfacial debondings are the primary failure mechanisms of the yarn-reduction composites, while yarn breakages and yarn pulling-outs are the main failure modes of the cut composites.

Bending properties of particleboard and MDF layers

Holzforschung ◽  
2007 ◽  
Vol 61 (6) ◽  
pp. 717-722 ◽  
Author(s):  
Arnold Wilczyński ◽  
Marek Kociszewski
Keyword(s):  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Medium Density Fiberboard ◽  
Core Layer ◽  
Longitudinal Axis ◽  
Relative Difference ◽  
Layered System ◽  
Bending Properties ◽  
The Core ◽  
The Face

Abstract The modulus of elasticity in bending and the bending strength of the face and core layer of particleboard and medium density fiberboard (MDF) were determined. Three directions of longitudinal axis of test specimens were considered: the direction of the mat forming, the direction perpendicular to it, and the direction perpendicular to the panel plane. The experiments were carried out on specimens that were prepared with strips of layers separated from the panels and glued into laminated assemblies. The bending properties of the core and face layer of the tested panels differed considerably. The core layer properties were on average more than 4 times smaller for particleboard and almost 3 times smaller for MDF. The relative differences between the bending properties were greater than the differences between the densities of the layers. The bending properties of the layers were almost isotropic in the planes of layers and very strongly anisotropic in the planes perpendicular to layers. The modulus of elasticity of the tested panels was calculated for the axis corresponding to the mat forming direction. The calculations were performed on the basis of the moduli of panel layers and based on the layered system theory. The results were compared with the modulus determined directly for entire panels. The relative difference between the compared moduli was found to be very small for both tested panels.

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