scholarly journals Assessment of Bending Properties of Sawn and Glulam Blackwood in Portugal

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 418 ◽  
Author(s):  
Carlos Martins ◽  
Sandra Monteiro ◽  
Sofia Knapic ◽  
Alfredo Dias
Keyword(s):  
Bending Strength ◽  
Longitudinal Vibration ◽  
Raw Material ◽  
Bending Test ◽  
Mean Values ◽  
Four Point Bending ◽  
Structural Applications ◽  
Four Point Bending Test ◽  
The University ◽  
Non Destructive

Portuguese forests have changed in recent years. These changes were mainly boosted by the wildfires that affected a significant percentage of the softwood area. Data from 2015, conveyed by the Portuguese Institute for Nature Conservation and Forests, indicates that hardwoods occupy 70% of the Portuguese forest area. This paper presents the Blackwood (Acacia melanoxylon R. Br.) species potential, focusing on construction applications, based on recent studies performed at the University of Coimbra and SerQ—Forest Innovation and Competences Center. The valuation of Blackwood for structural applications has been considered through the non-destructive and destructive assessment of their mechanical properties as sawn wood. Their potential was also assessed for a more technologically engineered wood product, the glulam. The dynamic modulus of elasticity (MOE) was estimated through the Longitudinal Vibration Method (LVM) and the Transformed Section Method (TSM); the static MOE and bending strength were assessed through a four-point bending test. Agreement was obtained between both approaches. Sawn Portuguese Blackwood showed a density of 647 kg/m3, 13,900 MPa of MOE and a bending strength of 65 MPa (mean values). The glulam beams fabricated with this raw material had improved properties relative to sawn wood, most obviously concerning the bending strength, with an improvement of 29%. This proves the significant ability and potential of these species to be used in construction products with structural purposes like sawn wood and glulam.

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.

EFFECTS OF BAMBOO ON FRACTURE CHARACTERISTICS OF BAMBOO REINFORCED CALCIUM CONCRETE MEMBER

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Atsushi Shimabukuro ◽  
Mitsuaki Yamato
Keyword(s):  
Bending Strength ◽  
Bending Test ◽  
Concrete Member ◽  
Engineering Material ◽  
Fracture Characteristics ◽  
Fracture Properties ◽  
Four Point Bending ◽  
Reinforcement Material ◽  
Four Point Bending Test ◽  
Environmental Burdens

The calcium-based solidification material enables us to expect the reduction of environmental burdens because it is near-neutral. We defined the concrete using this material as Calcium (Ca) concrete, and we have performed some experiments to investigate the properties of this concrete. From these results of previous experiments, we think that Ca concrete will be effective material on strength as a new civil engineering material. However, it is difficult to use steel as reinforcement material in Ca concrete due to near-neutral. Therefore, the bamboo is used as reinforcement material in this paper. And, the effect of bamboo as reinforcement material in Ca concrete is examined by investigating the fracture properties of Ca concrete reinforced by bamboo from four-point bending test. In particular, this investigation pays attention to the effect of the number of reinforcing bamboo. As a result, it becomes clear that the bending strength of Ca concrete with reinforcing bamboo is stronger than the strength of Ca concrete without reinforcing bamboo.

Cement Composite Reinforced with Synthetic Fibers: Comparison of Three-Point and Four-Point Bending Test Results

2016 ◽  
Vol 827 ◽  
pp. 332-335 ◽  
Author(s):  
Jaroslav Topič ◽  
Jan Bartoš ◽  
Lubomír Kopecký ◽  
Karel Šeps ◽  
Zdeněk Prošek ◽  
...  
Keyword(s):  
Bending Strength ◽  
Cement Composite ◽  
Bending Test ◽  
Test Results ◽  
Recycled Pet ◽  
Bending Tests ◽  
Synthetic Fibers ◽  
Four Point Bending ◽  
Pet Fibers ◽  
Four Point Bending Test

Presented article deals with the influence of PET fiber production on the bending strength of cement-based composite when incorporated into the fresh mortar, and comparison of results of 3-point and 4-point bending test. Cement paste samples were reinforced with 2 wt. % of primary or recycled PET fibers. The bending test was performed on prismatic samples with dimension of 40 × 40 × 160 mm. It was found that samples with recycled PET fibers, compared to primary ones, exhibit a decrease in bending strength. In the case of 4-point bending tests, the samples with recycled PET fibers exhibited higher bending strength than reference samples without any fibers. However, in the case of 3-point bending tests, the samples with recycled PET fibers had lower bending strength than the reference ones. The results suggest that recycled PET fibers could be used as an alternative to reinforce cement-based composites.

Strengthening of Si3N4 Ceramics by Laser Peening

2006 ◽  
Vol 524-525 ◽  
pp. 141-146 ◽  
Author(s):  
Koichi Akita ◽  
Yuji Sano ◽  
Kazuma Takahashi ◽  
Hirotomo Tanaka ◽  
Shin Ichi Ohya
Keyword(s):  
Surface Roughness ◽  
Bending Strength ◽  
Laser Pulses ◽  
Bending Test ◽  
Laser Peening ◽  
Test Results ◽  
X Ray Diffraction ◽  
Four Point Bending ◽  
Four Point Bending Test ◽  
Si3n4 Ceramics

Laser peening has been applied to silicon nitride (Si3N4) ceramics without any pre-coating. X-ray diffraction study revealed that plastic strain was introduced into the surface layer of the ceramics. Compressive residual stress was also imparted, which became larger with increasing peak power density of irradiated laser pulses. Surface roughness significantly increased due to ablative interaction of the surface with laser pulses. A Weibull plot of four-point bending test results clearly showed the increase of the bending strength and Weibull modulus by laser peening in spite of the increase of the surface roughness.

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