Kind Of Reinforcement Research Articles

Experimental Investigations on Punching Shear of Flat Slabs Made from Lightweight Aggregate Concrete

Abstract In the paper the results of experimental investigations concerning flat slabs made from reinforced lightweight concrete with sintered fly ash aggregate CERTYD were presented. In the research program 6 models made in a natural scale were included. The main variable parameter was slab longitudinal reinforcement ratio. The aim of investigation was the experimental verification of efficiency of double-headed studs as punching shear reinforcement. In the existing technical approvals such kind of reinforcement was allowed only in normal concrete slabs. It was demonstrated that double-headed studs can be an effective transverse reinforcement of lightweight aggregate concrete slabs. The use of double-headed studs resulted in increase in the ultimate load from 19% to 44%, depending on the slab reinforcement ratio which ranged from 0.5% to 1.2%. The comparative analysis showed that the Eurocode 2 provisions were conservative in relation to the experimental results, which were on average 42% higher than the theoretical ones however with a very low 7% coefficient of variation.

Experimental investigation on the enhancement of Mode I fracture toughness of adhesive bonded joints by electrospun nanofibers

ABSTRACTThe use of an electrospun nylon nanofibrous mat at the interface between adjacent plies of a composite laminate is a promising mean to improve the delamination strength, as the nanomat acts a reinforcing web enabling a ply-to-ply bridging. This kind of reinforcement can be potentially used in other applications, such as adhesive bonding, where it may also work as adhesive carrier. The present work is therefore aimed at analysing the potential of an electrospun polymeric nanomat as adhesive carrier and reinforcing web in adhesive bonding. The adhesive is used to pre-impregnate a nylon nanofibrous mat that is then placed at the interface between two metal pieces and cured. The effectiveness of this procedure is evaluated by comparing of the mode-I fracture toughness measured 2024-T3 aluminum alloy DCB (Double Cantilever Beam) specimen bonded using a two-part epoxy resin with and without the nanomat.

Performance of rock–soil slope reinforcement and protection effect in cutting slope construction

It is inevitable to excavate slide slope and damage rock slope under the rapid development of expressway. To further remedy ecological environment, correct understanding of side slope stability is essential for the effective reinforcement and protection of rock–soil slope. In this paper, the reinforcement and protection technologies of cutting slopes were introduced firstly, and then the classifications of rock–soil slope reinforcement technologies in China and abroad were compared. Taking the Daqing–Guangzhou Highway as the research subject, three kinds of reinforcement and protection schemes were proposed and analyzed. Combing fuzzy comprehensive judgment with analytic hierarchy process, a supporting model of cutting slopes was established. The analytic hierarchy process was used to determine the weight and the degree of membership was calculated. Finally, the model was applied into the project to carry out evaluation. The results showed that the fuzzy comprehensive evaluation model used in this paper had a good reference value for the future development of cutting slopes.

A Minimaxmax Problem for Improving the Torsional Stability of Rectangular Plates

We use a gap function in order to compare the torsional performances of different reinforced plates under the action of external forces. Then, we address a shape optimization problem, whose target is to minimize the torsional displacements of the plate: this leads us to set up a minimaxmax problem, which includes a new kind of worst-case optimization. Two kinds of reinforcements are considered: one aims at strengthening the plate, the other aims at weakening the action of the external forces. For both of them, we study the existence of optima within suitable classes of external forces and reinforcements. Our results are complemented with numerical experiments and with a number of open problems and conjectures.

Tribological behaviour of Magnesium Metal Matrix Composites reinforced with fly ash cenosphere

Now a day’s metal matrix composites are used in many industries such as aerospace and automobiles. The demand of magnesium metal matrix composites has increased in these industries mainly due to its high specific strength, better damping properties, excellent cast ability, and superior machinibility. The need of high performance and light weight material for some demanding application has led to the development of magnesium matrix composites and cost effective fabrication techniques. Tribology is a science and engineering that deals with the study and application of the principle of friction, lubrication and wear. This review article is mainly concentrated on the wear and frictional behaviour of magnesium metal matrix composites when they are reinforced with various kinds of reinforcements.

Evaluation of Wear characteristics of Aluminium 7075 based Metal Matrix Composite

In this present investigation, efforts are made to study the Wear rate of as-cast Tungsten carbide particulates and Short E-glass fibers reinforced AA7075 Hybrid Composites. The vortex method of stir casting was employed, in which the reinforcements were introduced into the vortex created by the molten metal by means of the mechanical stirrer. Castings were machined to the ASTM standards on a highly sophisticated lathe. The degree of improvement of Wear characteristics of MMCs is strongly dependent on the kind of reinforcement. An improved Wear characteristic occurs on reinforced compared to Unreinforced MMCs alloys.

Analysis of Families’ Perceptions on Reinforcement usage for Teaching Daily Life Skills to Children with Mild Intellectual Disabilities

In this study, it was aimed to find out if families of children with mild intellectual disability use reinforcement in teaching daily living skills, what kind of reinforcements and reinforcement schedules they use and to learn if they found it effective. This study was based on qualitative research method. The study group of this study consists of 48 families, who have children with mild intellectual disabilities. The research data were obtained from interviews with families via the interview form. To analyze the data, content analysis technique was used. According to the results of the study, consciously or unconsciously families use reinforcements in teaching daily living skills. All types of reinforcements appeared to be used by families but only continuous, variable ratio and interval ratio reinforcement schedules have been found to be used. Reinforcement was used by the families at all age groups, and the families determine the reinforcement with regard to child’s condition and needs and their material and spiritual conditions. One of the most striking results of the study was that families did not have education and elementary school graduates used reinforcements and found it quite useful.

Interface improvement of multi axial warp-knitted layer composite with short glass fiber

Inter layer performance enhancement with short glass fiber provides a feasible approach for improving inter layer tearing strength of glass fiber reinforced plastic (GFRP) composites. The effects of laying short glass fiber (SGF) between two layers of glass fiber fabrics were studied, including vacuum assisted resin transfer molding (VARTM), SEM analysis of interlayer after tests, layer tearing property and data calculation analysis. The experimental results showed that: (1) the tearing strength of the GFRP toughened by short glass fiber increased by 48.13 % than that the GFRP without any toughening treatment, and (2) the damaged samples observed under SEM showed different interface and inter layer morphologies, mechanism of action of five kinds of reinforcement has been analyzed. In this study, the calculation analysis revealed that SGF (20 mm) can make inter layer tearing property enhanced greatly, it is the best in these five kinds of GFRP, GFRP with the reinforcement nap glass fiber fabric has the worst inter layer tearing property of this five.

Synthesis and tribological properties of AA5052-base insitu composites

It is important to optimize the properties of a material for a particular application, hence, to find the suitable material for tribological applications, the wear and friction behaviour of AA5052 in situ composites with different kind of reinforcements have been investigated. For present study, three in situ formed composites have been produced with different reinforcements namely Al3Zr, ZrB2 and combination of both (Al3Zr + ZrB2) by direct melt reaction (DMR) technique. The as-cast composites and base alloy have been characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy, tensile testing, hardness and dry sliding wear and friction tests. XRD results indicate the successful formation of second phase reinforcement particles in all composites. Wear test results indicate that the cumulative volume loss increases with an increase in sliding distance while coefficient of friction shows a fluctuating tendency, whereas with increasing applied load, wear rate shows an increasing trend while coefficient of friction shows decreasing trend. The variation of wear rate with composites indicates that the composite with multiple reinforcement (Al3Zr + ZrB2) has lowest wear rate among all as-cast composites and base alloy, while coefficient of friction is higher. The responsible mechanisms concerned with wear and friction results have been discussed in detail with the help of the observation on worn surface analysis by scanning electron microscope (SEM) and 3D-profilometer. All tribological results have been correlated with the microstructural properties, strength parameters and bulk hardness of the composites.

Blast resistance characteristics of concrete with different types of fibre reinforcement

AbstractThis paper summarizes the results of the development of advanced fibre‐reinforced concrete intended for explosion‐resistant applications. Experimental research was carried out with the aim of contributing to understanding the effect of different types of reinforcement on the behaviour of high‐performance fibre‐reinforced concrete subjected to a blast load. The fine‐grained concrete matrix was reinforced by various types of dispersed fibre – metallic, carbon, mineral and polymer – in different lengths (6–55 mm) and combinations, while the volume content (3 %) of fibres was kept constant. Physico‐mechanical and explosion tests were performed on prismatic and slab‐shaped specimens and the effect of different kinds of reinforcement on the blast resistance and mechanical performance of the concrete samples was evaluated. The accelerations of the specimens within the blast load were ascertained. The material characteristics and explosion test data obtained were used to create a finite element model in LS‐DYNA. The numerical and experimental investigations resulted in the design of concrete elements for population protection which are able to resist an explosion defined by the weight and placement of the charge. The resistance of the newly designed concrete element was confirmed by a field blast test.

The Reinforcement of Multiculture-Based Curriculum For Students of Foreign Nationalities in Indonesian Schools

Multicultural curriculum in Indonesia is developed for students with multicultural backgrounds to internalize multicultural values without having to lose their own cultural identity. A multicultural curriculum is designed to promote teaching methods developed based on the diversity of the students themselves with the purpose of educating them to understand pluralism, humanism, and democracy and to respect each other both inside and outside the school. Such a multicultural curriculum proves to be a barrier for students with non multicultural backgrounds. Their different backgrounds limit their understanding of the diversity. This situation requires a new curriculum. This article is the result of the Competitive Grants research regarding multicultural curriculum for students of foreign nationalities. The interviews with the participants of IACS (Indonesian Art Culture Sholarship) program in 2013 and 2014 have indicated that classroom discussions and direct interaction with the local community could become some kind of reinforcement for the formation of a new curriculum for students with foreign nationalities to better understand the diversity of Indonesia instead of art and cultural education.

Experimental Investigation of Mechanical Properties of Al7075 Hybrid Reinforced with Mica Particulates and E-Glass Fibres

In this present investigation efforts are made to study the mechanical properties of as cast Mica particulates and Short E-glass fibers reinforced AA7075 Hybrid composites containing mica particulate of 200 microns and short E-Glass fibers of 2-3 mm length in different compositions. The vortex method of stir casting was employed, in which the reinforcements were introduced into the vortex created by the molten metal by means of mechanical stirrer. Castings were machined to the ASTM standards on a highly sophisticated lathe. The degree of improvement of mechanical properties of MMCs is strongly dependent on the kind of reinforcement. An improved mechanical properties occurs on reinforced compared to Unreinforced MMCs alloys.

Glass - steel hybrid elements under four point bending test

Problems evolving from the brittleness of structural glass result in need of innovative solutions which will improve the post-breakage behaviour of the elements in the structure. As the need of the glass performance gets higher, the fully tempered glass gets in the focus and its usage becomes greater. But although this type of glass gives great performance with its tensile strength and deflection capaciy, it has no residual strength. Due to its breakage pattern into small pieces the collapse of the element may be instant even in laminated glass elements. Thus, increasing the post breakage behaviour is crucial in order to keep the integrity of the tempered glass element. This can be done either by changing the interlayer properties, or including kind of reinforcement in the element structure. This paper presents experimental testing of the performances of steel plate reinforced hybrid glass element under four point bending test. As a result, it shows the improvement in mechanical behaviour of the described hybrid structure concept compared to a monolithic glass element with same dimensions, by means of stress distribution and reinforcement capacity.

The effectiveness of using reinforcements in the classroom on the academic achievement of students with intellectual disabilities.

The purpose of this study was to compare the effectiveness of two kinds of reinforcements, tangible reinforcements and social reinforcements, on the academic achievement of eighth-grade female students with intellectual disabilities in the science subject. The study was an experimental method by pretest, with a control group. The participants of the study comprised 45 female students with intellectual disabilities from three different middle schools in the province of Tehran. The multistage cluster method was chosen to determine the sample. The Wechsler intelligence test for matching the groups in terms of IQ and teacher-applied tests were used for all students to measure the progress of students in science. Data were analyzed by one-way analysis of variance. The results showed that (a) there was a significant difference in the academic achievement scores of the groups after applying the intervention and (b) the mean difference in achievement scores for the tangible reinforcements group was significantly higher than the social reinforcement group and the control group. Also the mean scores for the social reinforcement group were significantly higher than the control group.

The Impact of Gagné, Vygotsky and Skinner Theories in Pedagogical Practices of Mathematics Teachers in Brunei Darussalam

Pedagogy in a classroom is not just for the sake of teaching but it also embodies the learning process where appropriately correct conceptual knowledge is being transferred to the learners. Educational theories that we currently come to know play an important role in the effectiveness of the teaching and learning processes. In this study, the teaching practices of three Mathematics teachers in one of the secondary schools in Brunei Darussalam were observed and examined based on the work of three educational theorists, Robert Mills Gagne, Lev Semyonovich Vygotsky and Burrhus Frederic Skinner. The observational vantage points of the research focused on the learning conditions of the lesson, students’ interaction with their teachers and peers, and the teachers’ responses to their learners’ behaviour during the lesson. The qualitative reports indicated that the most commonly “not seen” events by the three teachers were gaining students attention, assessing the performance and enhancing retention and transfer; social interactions for example, discussions were absent in all three observed lessons; and all the three teachers gave some kind of reinforcements, such as praises and extra activities, during their lessons.

Effect of Ni-coated short carbon fibers on the mechanical and electrical properties of epoxy composites

Ni-coated short carbon fibers (Ni-SCFs) were prepared using an electrodeposition method. Short carbon fiber (SCF) reinforced epoxy composites were prepared by changing the fiber content (0.1–0.7 wt%). To investigate the effect of Ni-coated short carbon fibers on the mechanical and electrical properties of the composites, we prepared two kinds of reinforcements: the short carbon fibers treated by 400 °C (400 °C treated SCFs) and Ni-SCFs. Fracture characteristics of the composites revealed the Ni coatings and the epoxy matrix had a better interface, so that the results of tensile and bending strength were better in epoxy/Ni-SCFs composites than those in epoxy/400 °C treated SCFs composites. The 400 °C treated SCFs decreased the electrical resistivity of the epoxy composites, compared to the pure epoxy. However the epoxy/Ni-SCFs composites had lower electrical resistivity than epoxy/400 °C treated SCFs with the same fiber content.

Carbon fiber-reinforced rectangular isolators with compressible elastomer: Analytical solution for compression and bending

The behavior of multilayer elastomeric isolators employing carbon fibers as reinforcement material rather than steel has been considered. This kind of reinforcement is used to make the isolators lighter and cheaper, since carbon fibers (or Kevlar) are much more resistant per unit weight than steel. From the mechanical point of view, the main difference is that the fiber reinforcement cannot be considered rigid in extension as it is usually done for steel plates. In this paper an analytical model to analyze the compression and bending behavior of fiber-reinforced rectangular isolators is presented. The model takes into account, for the first time, both the reinforcement extensibility and the compressibility of the elastomer. An analytical solution to predict deformations, stresses and stiffness is here determined in terms of Fourier series, both for compression and bending.

Exploration of Al Matrix Composites Reinforced with Al-Ti Intermetallics/Ti Metal Compound Spherical Agents

In this paper, Al matrix composites reinforced with Al-Ti intermetallics/Ti metal compound spherical agents were successfully fabricated through powder metallurgy way. Al-Ti intermetallic including Al3Ti and TiAl phases are main reinforcements and inner Ti metal could not only play reinforce role but also reduce the crack sensitivity of Al-Ti intermetallics. This kind of reinforcements bonded strongly with Al matrix. As expected, the resultant composites exhibit promising mechanical properties at ambient temperature. And the mechanical property could be improved through regulating the relative thickness of the Al-Ti intermetallics and Ti metal layers.

Experimental Research on Shear Behavior of Reinforced Concrete Beams with High-Strength Stirrup under Uniform Load

According to tests of 8 T concrete beams with HRB500 steel bars as stirrup, the shear behavior of beams was researched under uniform load, and the influencing factors of diagonal crack width were analyzed, such as the different concrete strength, stirrup spacing and the welded wire fabric. Experimental results show that concrete beams with HRB500 steel bars as stirrup show similar behavior to the beams with conventional stirrup, and the stirrups yield can be achieved which meets the requirement of shear behavior in structure. In addition, the welded wire fabric can be used as one of the new kinds of reinforcement to control diagonal crack width.

Interfacial Shear Strength of Carbon Fiber Reinforced Polypropylene

In this study, interfacial shear strength of carbon fiber reinforced polypropylene were investigated. Two kinds of reinforcements are used. One is non-treated carbon fiber, another is acetone-treated carbon fiber. And two kinds of matrices are used. One is non-treated polypropylene, another is maleic anhydride-polypropylene. Three point flexural tests and micro debonding tests are conducted. As a result, following conclusions are obtained. Acetone treatment and maleic anhydride are effective to the adhesives on the surface between fiber and matrix. But simultaneous treatments are not effective. The shear strength is not dependent on fiber embedded length. The contact angle and fracture load are dependent on fiber embedded length. The interfacial strength is dependent on the contact angle. As the contact angle increases, the interfacial strength increases.