scholarly journals The flexural strength of glue laminated timber beams based on deflection and strain rate with four point bending loading system

2022 ◽  
Vol 1212 (1) ◽  
pp. 012034
Author(s):  
S Maricar ◽  
K Sulendra ◽  
H Listiawaty ◽  
H O Baide
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Wood Species ◽  
Urea Formaldehyde ◽  
Compressive Force ◽  
Bending Test ◽  
Laminated Beams ◽  
Laminated Beam ◽  
Four Point Bending ◽  
External Reinforcement

Abstract The development of utilization of low quality wood as construction material is needed to reduce the exploitation of natural forests. However, low quality wood species have disadvantages in terms of mechanical properties. The mechanical properties of Sengon wood are relatively low, so it does not qualify as a structural element. Therefore, the system glulam can be applied to overcome this problem. The system glulam can produce relatively light structural elements with adequate performance. This system has been extensively developed, even at the stage of applying external reinforcement, to improve the performance of structural laminated beams. On that basis, this study aims to determine the flexural strength of laminated beams of Sengon wood as a low quality wood species. In order to achieve this goal, the laminated beam was tested using method four point bending test method. Tests were carried out on long span laminated beams (L = 2750 mm) to observe flexural strength. There are five (5) laminated blocks tested, namely (BLS-1, BLS-2, BLS-3, BLS-4 and BLS-5). Each group has dimensions of 55 mm in width and 155 mm in height. Each specimen consists of six layers of wood boards with a density Falcata 0.3 g / cm3. The thickness of each layer was 26 mm and bonded with resin urea formaldehyde cold setting. Double-sided adhesive laying of 350 gr / m2 at a compressive force of 2 MPa. The analysis result shows that the load-deflection relationship between BS-L consists of linear and nonlinear phases. The load performance characteristics of the two types of laminated beams are expressed as the ratio of the proportional limit load to the maximum load. The ratio value is expressed in the form P eBL-s = 0.7P max BL-S andM eBL-s = 0.7M max BL-S. This form is similar to previous studies with a Pe to Pmax ratio of 0.80.9. In this case, the average flexural strength of the laminated beam is 17 MPa with a maximum strain of 0.004.

High Temperature Mechanical Properties of a Crystallized BaO-B2O3-Al2O3-SiO2 Glass Ceramic for SOFC

2009 ◽  
Author(s):  
Hsiu-Tao Chang ◽  
Chih-Kuang Lin ◽  
Chien-Kuo Liu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Stress Relaxation ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Testing Temperature ◽  
Bending Test ◽  
High Temperature Mechanical Properties ◽  
Four Point Bending ◽  
The Given

The high temperature mechanical properties in a glass-ceramic sealant of BaO-B2O3-Al2O3-SiO2 system was studied by four-point bending test at room temperature, 550°C, 600°C, 650°C, and 700°C, to investigate the variation of Young’s modulus, flexural strength, and stress relaxation. Weibull statistic analysis was applied to describe the fracture strength of the given glass ceramic. The crystalline phase was produced by controlled heat treatment and analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the flexural strength was enhanced at high temperatures when the testing temperature was below the glass transition temperature (Tg). This was presumably due to a crack healing effect taking place at high temperature. Significant stress relaxation for the given glass ceramic was observed to generate extremely large deformation without breaking the specimens when the testing temperature was set at 700°C.

Flexural Behavior of Six Species of Italian Bamboo

2022 ◽  
Author(s):  
Silvia Greco ◽  
Luisa Molari
Keyword(s):  
Structural Material ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Functionally Graded ◽  
Flexural Behavior ◽  
Bending Test ◽  
Bamboo Species ◽  
Four Point Bending ◽  
Flexural Ductility ◽  
Graded Material

The good mechanical performance of bamboo, coupled with its sustainability, has boosted the idea to use it as a structural material. In some areas of the world it is regularly used in constructions but there are still countries in which there is a lack of knowledge of the mechanical properties of the locally-grown bamboo, which limits the spread of this material. Bamboo is optimized to resist to flexural actions with its peculiar micro structure along the thickness in which the amount of fibers intensifies towards the outer layer and the inner part is composed mostly of parenchyma. The flexural strength depends on the amount of fibers, whereas the flexural ductility is correlated to the parenchyma content. This study focuses on the flexural strength and ductility of six different species of untreated bamboo grown in Italy. A four-point bending test was carried out on bamboo strips in two different loading configurations relating to its microstructure. Deformation data are acquired from two strain gauges in the upper and lower part of the bamboo beam. Difference in shape and size of Italian bamboo species compared to the ones traditionally used results in added complexity when performing the tests. Such difficulties and the found solutions are also described in this work. The main goal is to reveal the flexural behavior of Italian bamboo as a functionally graded material and to expand the knowledge of European bamboo species toward its use as a structural material not only as culm but also as laminated material.

scholarly journals Effect of Gamma Radiation and Endodontic Treatment on Mechanical Properties of Human and Bovine Root Dentin

2016 ◽  
Vol 27 (6) ◽  
pp. 670-674 ◽  
Author(s):  
Veridiana Resende Novais ◽  
Priscilla Barbosa Ferreira Soares ◽  
Carlla Martins Guimarães ◽  
Laís Rani Sales Oliveira Schliebe ◽  
Stella Sueli Lourenço Braga ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Gamma Radiation ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Endodontic Treatment ◽  
Bending Test ◽  
Human Teeth ◽  
Significant Difference ◽  
Root Dentin

Abstract This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single-rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect.

scholarly journals Nonthermal plasma modification of polypropylene fibres for cementitious composites

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Tomáš Morávek ◽  
Monika Fialová ◽  
Daniel Kopkáně ◽  
Jozef Ráheľ ◽  
Pavel Sťahel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Plasma Treatment ◽  
Nonthermal Plasma ◽  
Bending Test ◽  
Plasma Modification ◽  
Surface Barrier ◽  
Polypropylene Fibres ◽  
Temperature Plasma ◽  
Concrete Matrix

AbstractThe plasma treatment of polypropylene fibres used as concrete admixtures for improving its mechanical properties is the focus of this research paper. A plasma treatment was conducted in a low-temperature plasma environment at atmospheric pressure in a DCSBD (Diffuse Coplanar Surface Barrier Discharge). The degree of hydrophilicity caused by the plasma treatment was determined by measuring the rate of penetration of water into the porous media, commonly referred to as the Washburn method. The influence of the addition of PP (polypropylene) fibres to the concrete matrix was investigated using a three point bending test which determined the flexural strength of concrete samples. Our experiments demostrate that plasma improves both the wettability of PP fibres and its adhesion to the concrete matrix. The tests of flexural strength show, that even a short plasma treatment (5 s) can have a significant impact on the mechanical properties of fibre-reinforced concrete composite.

THE INFLUENCE OF SiC COATING PROCESS ON THE PROPERTIES OF C/C COMPOSITES

2007 ◽  
Vol 14 (04) ◽  
pp. 817-820
Author(s):  
MIN HUANG ◽  
KE-ZHI LI ◽  
HE-JUN LI ◽  
QIAN-GANG FU ◽  
GUO-DONG SUN
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Failure Mode ◽  
Flexural Modulus ◽  
Pack Cementation ◽  
Bending Test ◽  
Carbon Composites ◽  
Coating Process ◽  
Three Point Bending ◽  
Coated Carbon

SiC coating for carbon/carbon composites was prepared by pack cementation method. The effects of coating process on the microstructure and the mechanical properties of C / C composites were analyzed by SEM and three-point bending test, respectively. As the infiltrated Si improved the interfaces bonding during the coating process, the flexural strength and flexural modulus of SiC -coated carbon/carbon composites were both increased by about 10% than the naked C / C composites. In addition, the mechanism of the change of failure mode of SiC coated C / C composites and naked C / C composites was addressed.

scholarly journals Influence of a Repeated Preheating Procedure on Mechanical Properties of Three Resin Composites

2015 ◽  
Vol 40 (2) ◽  
pp. 181-189 ◽  
Author(s):  
M D'Amario ◽  
F De Angelis ◽  
M Vadini ◽  
N Marchili ◽  
S Mummolo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Vickers Microhardness ◽  
Flexural Modulus ◽  
Bending Test ◽  
Resin Composites ◽  
Three Point Bending ◽  
Main Effect ◽  
Dependent Variables ◽  
Marginal Means

SUMMARY The aim of this study was to assess the flexural strength, flexural elastic modulus and Vickers microhardness of three resin composites prepared at room temperature or cured after one or repeated preheating cycles to a temperature of 39°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium), Opallis (FGM), and Ceram X Duo (Dentsply DeTrey). For each trial, one group of specimens of each material was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 1, 10, 20, 30, or 40 preheating cycles to a temperature of 39°C in a preheating device. Ten rectangular prismatic specimens (25 × 2 × 2 mm) were prepared for each group (N=180; n=10) and subjected to a three-point bending test for flexural strength and flexural modulus evaluation. Vickers microhardness was assessed on 10 cylindrical specimens from each group (N=180; n=10). Statistical analysis showed that, regardless of the material, the number of heating cycles was not a significant factor and was unable to influence the three mechanical properties tested. However, a significant main effect of the employed material on the marginal means of the three dependent variables was detected.

scholarly journals Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

2009 ◽  
Vol 20 (2) ◽  
pp. 132-137 ◽  
Author(s):  
Rafael Leonardo Xediek Consani ◽  
Douglas Duenhas de Azevedo ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
Paulo César Saquy
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Denture Base ◽  
Acrylic Resins ◽  
The Impact

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

Effect of Filler Content and Waiting time Before Light-Curing on Mechanical Properties of Dual-Cured Cement

2020 ◽  
Vol 2 (1) ◽  
pp. 45-52
Author(s):  
Ana C. de Assunção Oliveira ◽  
Sandro Griza ◽  
Rafael R. de Moraes ◽  
André L. Faria-e-Silva
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Waiting Time ◽  
Filler Content ◽  
Bending Test ◽  
Resin Cements ◽  
Three Point Bending ◽  
Light Curing ◽  
Curing Procedure

Objective:: To investigate the effect of filler content and the time spent before light-curing on mechanical properties of dual-cured cement. Methods:: Experimental dual-cured resin cements were formulated with 60, 65 or 68wt% of filler. The viscosity of experimental cement was measured using a digital viscometer. Bar-shaped specimens (25 x 2 x 2 mm) were fabricated, while the light-curing was started immediately or 5 minutes after the insertion of cement into the mold (n = 7). A three-point bending test was performed and the values of flexural strength and elastic modulus were measured. The Vickers hardness of fractured specimens was measured on the surface of the cement. Data from viscosity were submitted to oneway ANOVA, while the data from mechanical properties were analyzed by two-way ANOVA. All pair-wise comparisons were performed using Tukey’s test (α = 0.05). Results:: The experimental cement with 68wt% of filler showed the highest viscosity and those with 60wt% showed the the lowest viscosity. Irrespective of the time spent before light-curing, the cement with 65wt% of filler presented the highest values of flexural strength and elastic modulus. The addition of 60wt% of filler resulted in the lowest elastic modulus, while 68wt% of filler resulted in lowest flexural strength. Regarding the hardness, the cement with 68wt% of filler showed the highest values, while there was no difference between 60 and 65wt% of filler. Conclusion:: Filler content affected the mechanical properties of the experimental cement and this effect did not depend on the waiting time before the light-curing procedure.

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