Papers by Keyword: Bending Strength

Abstract: This study is undertaken to provide a viable alternative to destructive test assessment which is prohibitively costly and makes it difficult to fully capture the bending strength distribution of timber. The bending strength of glued laminated Nigerian wood specie which from previous research have clearly not been sufficiently studied were carefully evaluated under controlled conditions. Five wood species—Afara (Terminalia superba), Akomu (Pycnanthus angolensis), Melina (Gmelina arborea), Iroko (Milicia excelsa), and Omo cedar (Stereospermum accuminatissmum)—were tested for physical and mechanical properties at a mean moisture content level of 13%. Using standard procedures, density was determined for the wood species and found to be within low and medium densities. The glulam beams were produced using Phenol resorcinol formaldehyde, Urea formaldehyde, and Polyurethane adhesives. Furthermore, the bending strength of the beams was assessed parallel and perpendicular to the glue line using central point loading. Based on the strength assessment, four variables were evaluated as determinants for bending strength. These were wood density, wood species, adhesive type, and load direction. Analysis of variance was conducted to evaluate the significance of these variables as bending strength determinants in the beams. Furthermore, a stepwise regression method was used to develop the models, from which three models emerged with density, wood species, and load direction as predictors. Finally, these models were validated using an in-sample technique by splitting the data into a validation group and a training group in a ratio of 20% to 80%, respectively. The Pearson correlation between the predicted and experimental data was 0.847, 0.917, and 0.916 in the validation group and 0.824, 0.875, and 0.877 in the training group for models 1, 2, and 3, respectively. Higher correlation with the experimental data was found in the validation group than in the training group, thereby validating the models. These models are recommended for use because of the simplicity and efficiency of prediction.

Abstract: This research aims to analyze the mechanical behavior of concrete reinforced with polyolefin fibers. The intention is to evaluate the possibility of using concrete as a structural material without steel bars in its interior. For this purpose, specimens with different dosages of polyolefin fibers were prepared, and bending and compression tests were carried out. The results show no significant increase in mechanical strengths, especially in bending, but it is interesting in the mechanical behavior after the first cracking. Controlling cracking is considered beneficial for sustainability.

Abstract: This paper reports on the influence of material position towards the bending strength of the 4 pass AA1050/AA6082 and AA6082/AA1050 FSPed joints. FSW approach was utilized to create dissimilar joints using two dissimilar plates. After that, the created dissimilar joints were put through a multi-pass friction stir processing. The microstructural analysis results revealed that the 4P 6082/1050 joint had substantially finer grains than the 4P 1050/6082 joint. The 4P 1050/6082 joint yielded the highest ultimate tensile strength when compared to that of the 4P 6082/1050 joint. The Vickers microhardness of 1050/6082 FSPed joints was found to be increased towards the AA6082, while 6082/1050 FSPed joints decreased towards AA1050. The bending strength analysis showed that there was no obvious trend in flexural strength.

Abstract: The physical (density and moisture content) and chemical properties of the oil palm trunk (OPT) were examined. The effect of different densities (500, 600, and 700 kgm^-3) and different percentages of urea-formaldehyde (UF) resin content (8, 10, and 12%) on the single layer at the different portions of OPT particleboard were evaluated for mechanical and dimensional stability. The results showed that the bottom portion and near bark had a positive result on density and moisture content. Lignin, holocellulose, and alpha-cellulose of the OPT showed the highest content at the bottom portion. The density was found to effect all the board properties significantly at p < 0.05 on the modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), thickness swelling (TS), and water absorption (WA) of the particleboards. For the resin content, all the board properties were effected except for the water absorption. The particleboards produced, from 700 kgm^-3 densities and 10% resin content, met the minimum requirement for the particleboard (Type 18) stipulated in the Japanese Industrial Standard (JIS A 5908). The particleboard manufacturing from OPT particles as the replacement for wood is very promising.

Abstract: The heat-induced behavior of strength characteristics demonstrated by a “steel – wood” composite has been studied. The study has revealed the bending strength of steel plates in contact with a wooden bar is maximal if treated by a flame retardant agent containing phosphorous and urea solution.

Abstract: Interpenetrating Phase Composites (IPC) belong to a special category of composite materials, offering great potential in terms of material properties due to the continuous volume structure of both composite components. While manufacturing of metal-ceramic IPC via existing casting and infiltration processes leads to structural deficits, semi-solid forming represents a promising technology for producing IPC components without such defects. Thereby, a solid open pore body made of ceramic is infiltrated with a metallic material in the semi-solid state. Good structural characteristics of the microstructure as the integrity of the open-pore bodies after infiltration and an almost none residual porosity within the composites have already been proven for this manufacturing route within a certain process window. On this basis, the following paper focuses on the mechanical properties such as bending strength of metal-ceramic IPC produced by using semi-solid forming technology. Thereby, the impact of the significant process parameters on these properties is analysed within a suitable process window. Furthermore, a fractographic analysis is carried out by observing and interpreting the fracture behaviour during these tests and the fracture surface thereafter.

Abstract: The Fiber Metal Laminate (FML) discussed here was made from Fiber Reinforced Polymer (FRP) composite, laminated by aluminum alloy sheet. The FRP composite panel was made from abaca fiber and polyester resin matrix. The objective was to study the bending strength of the FML with different fiber content. Five panels of abaca FRP were prepared using hand-lay-up methods. The weight content of the fiber in the panels were 0%, 3.56%, 5.18%, 8.94% and 12.22% respectively. The aluminum alloy sheet was laminated to the composite panel using epoxy super glue. The density of the FMLs were measured to confirm the fiber content in the panels. The bending specimen were prepared based on ASTM D-7264. The bending strength that represented by flexural stress of the FML panels were 53.15, 56.44, 46.80, 63.53 61.48 and 49.57 MPa, respectively. The result of the experiment showed that the content of abaca fiber significantly affects the bending strength of the FML. The highest bending strength (63.53 MPa) was produced by the FML with 5.18% fiber content. The result of the study showed that the bending strength of abaca FML was 19.5% higher than commercial FML (53.15 MPa). It was an indication that abaca fiber could be used to substitute the glass fiber in commercial FML.

Abstract: The object of study is a cement composite material with powdered utilized optical discs. The objective is to establish the dependences of the main strength characteristics – com-pressive strength, bending strength, and density – on the amount of waste added into the mix-ture and the water-cement ratio.The compositions of the mixtures for the production of the cement composite material samples consisted of the following components: cement, sand, powdered waste in the form of utilized optical discs and water.Based on the results of testing the samples, mathematical models have been developed which describe the dependences of the physical and mechanical properties of the cement com-posite material samples on the fraction of waste and water-cement ratio. It was found that with an increase in the amount of powdered waste added into the mixture, it reduces the compressive strength, bending strength, and density of the samples under study, however, the optimization of the water-cement ratio makes it possible to obtain equal strength compositions with a differ-ent fraction of waste.Component compositions of cement composite material mixtures with the addition of powdered utilized optical discs in the amount of 10 to 25 % of the total filler mass, which can provide construction products with a compressive strength class B20, are presented.

Abstract: The influence of modification of fiberglass in the cured state in the microwave electromagnetic field on the value of the limit stresses is significantly manifested when testing samples in the initial state. The increase in limit voltages is on average 7%. Tests of modified samples after exposure in full-scale conditions showed a decrease in the effect with an increase in the exposure time from 6% for exposure of 3 months to 3% for exposure of 8 months. This significantly increases the uniformity of the bending strength values in the batch, which is manifested in a decrease in the coefficient of variation of limit stresses relative to the control samples by 33%. Functional dependencies in the form of 2nd-order polynomials are obtained, which allow predicting the stability of products made of modified fiberglass for long-term operation under the influence of environmental factors with a confidence of up to 98%.

Abstract: Magnesium Oxide (MgO) board has been widely used in prefabricated lightweight steelframe wall systems and as the floor board covering component. It is a non-insulating sheathingboard product which consists of sustainable materials with the characteristics of fire resistance,weather-ability, strength, resistance to mold and mildew. Although MgO board has recentlyworldwide used in façade construction but the research data related to the laboratory work such asthe bending strength is still limited. The previous studies on the bending strength of MgO board arebased on various standards such as ASTM, JC688 and British Standard subjected to the productscharacteristics and patterns. Therefore, the bending strength values obtained were inconsistent andnot convincing. Thus, this paper aims to examine the bending strength of MgO board with threedifference thicknesses (6mm, 9 mm and 12 mm) based on BS EN 310:1993 subjected to threepoints bending test. The failure modes during three points bending test was observed and theexperimental results obtained were compared with the theoretical values and others relevantstandards. A total of thirty six specimens with twelve specimens for each thickness in two groupdirections namely longitudinal (length) and transverse (width) direction were tested. The specimenswere prepared based on BS EN 326-1:1994 and BS EN 325:2012. The maximum flexure load of thespecimens was recorded and arithmetic mean bending strength for each thickness was presented.The experimental results showed the tested MgO board was not achieved minimum bendingstrength for load bearing used. It is recommended to be used in non-load bearing façade claddingconstruction.