Search

Engineered Cementitious Concrete (ECC), widely known to be Bendable Concrete. The advantage of ECC is that it can be molded easily in the required form and it is utterly reinforced with short random fibers, both polymer, and non-polymer fibers. It is known for its good compressive, tensile and flexural behavior. To overcome the absence of strain hardening property in conventional concrete, ECC was instituted. In the sulfate chloride environment, the ECC material remains durable when compared to normal concrete. As per referred works of literature the fibers usage should not exceed 2%. In this study, four mixes were made. There were two mixes with mono fibered reinforcement and two mixes with hybrid fibered reinforcement. Here the PVA and Glass fibers are hybridized to reach the mechanical performance of the ECC mixes. Superplasticizer used here in this study, improves the workability and minimize the shrinkage cracks. As far as mechanical performance is concerned, hybrid fiber reinforcement of PVA and glass is shown to be high in compression, mono fiber reinforcement with glass is shown to be high in both tensile and flexure. [ABSTRACT FROM AUTHOR]

Mechanical behavior of glass microballoon (GMB) reinforced high density polyethylene (HDPE) matrix syntactic foams is investigated under tensile mode. GMB's are blended in HDPE using brabender and subsequently compression molded to form the syntactic foam sheets. GMBs with true particle density 200 kg/m3 are varied by 0, 20, 40 and 60 vol. % in HDPE matrix. With increase in microballoon content modulus is increases while strength decreases. Syntactic foams present lower fracture strain as compared to neat HDPE. Compression molded neat HDPE exhibited higher modulus and lower strength as compared to injection molded samples. Micrography is performed using scanning electron microscope for all the tested samples [ABSTRACT FROM AUTHOR]

The world’s tendency toward utilizing reused materials requests new items from natural resources and waste polymers. In this work, composites made from waste rubber particles (average particle size: 320 mesh) and sisal fiber in unidirectional form with matrix material as epoxy resin were prepared by hand lay-up method & investigated the mechanical properties for the influence of waste rubber particle loading in natural fiber composite. The effect of different loading of waste rubber particle (0,5,10,20 %wt) on the tensile and flexural strength was investigated. The results represent that 5%wt waste rubber particle loading composite shows maximum tensile and flexural strength & further increase in rubber particle loading shows decrease in tensile & flexural strength. [ABSTRACT FROM AUTHOR]

In this research prepared the polymer blend as a matrix from epoxy resin (EP) mixed with unsaturated polyester resin (UP) by different ratios (10, 20, 40 and 50)% for (EP/UP) Blends, achieve better ratio for impact strength as a function of well toughness; we can observed that the optimum value of this ratio (80:20)% for (EP/UP) blend, reinforced this blend by the magnesium oxide powder MgO by the different weight percentage (0, 4, 8 and 12)% as composite material, the mechanical properties tested (Tensile, Impact, Hardness), and thermal conductivity after and before reinforced. The results showed the increase impact strength and tensile strength after the reinforced but the increase nonlinear where the best value in ratio 8% and also hardness increase after reinforced by MgO also the thermal conductivity decrease after reinforced by the MgO and when increase the ratio of MgO decrease the thermal conductivity increase. [ABSTRACT FROM AUTHOR]

Sago starch is a seasonal based plantation and widely found in Asia country. Its application mainly in cooking such as biscuits and as a thickener in jellies. To further utilize its application, bioplastic from sago starch was developed. Due to its highly hydrophilic characteristic and poor mechanical properties, the addition of cellulose fibers extracted from sago waste was studied and presented in this paper. The films were prepared by solution casting and their characterizations were carried out in term of tensile properties, X-ray diffractograms, thermogravimetric analysis, wettability and water absorption behavior. The incorporation of cellulose fibers has successfully increased the properties of the sago starch films. The tensile strength and Young’s modulus increased significantly with the increase of cellulose fibers content while the elongation decreased. Thermal stability improved with the introduction of cellulose fibers. XRD patterns confirm the presence of cellulose fibers in sago starch film. [ABSTRACT FROM AUTHOR]

Room temperature curing of the polyester composites is time consuming and inferior in terms of the strength compared to the composites cured with the temperature. Hence, in this work, a range of the curing temperatures were employed and its influence on the tensile, impact and free vibration properties of the sisal/polyester composite. Composites are produced for the varying curing temperature ranges from 60°C to 100 °C in steps of 10 with hot compression molding process. Results indicate that the highest mechanical strength was recorded for the samples cured at 100° C. The free vibration properties such as natural frequency and damping factor were obtained from the impulse excitation technique. Both natural frequency and damping of the composites was found to vary with the changes in curing temperature. [ABSTRACT FROM AUTHOR]

Now a day’s material scientists are developing wood based composites as a alternative to conventional composites materials, the main reasons are wood fibers are eco friendly, can be easily processed also these composites have superior strength when compared to the conventional materials. In this study date palm fiber are extracted through mechanical retting method and used as reinforcement along with Polyester resin. Composite laminates are prepared using hand layup method. Different Samples of date palm fibers were collected from five different regions and specimens are prepared. Mechanical properties like Tensile, impact and flexural strength are evaluated. Also Fourier transforms infrared spectroscopes (FTIR) were used to analyse functional groups. [ABSTRACT FROM AUTHOR]

It is a certainty that a rock massif is a very complex environment, known only partially; in the laboratory we cannot produce all the details encountered in situ; therefore, most of the properties determined experimentally not fully express their real value that they have in rock massif. As theoretical basis we might consider theory of similitude initiated by Newton, in the sense of similarity that we can establish to the boundary between theory and experiment. Based on this and considering the applicable theorems that define main properties and recognition criteria of phenomena to different scales to which material systems are analyzed and implicitly rocks, we have studied the variation manner of rock characteristics established on specimens of different shapes and sizes. This paper presents the influence of scale effect under mechanical characteristics of rocks, as result of studies realized on both cubical and cylindrical specimens. Increasing of geometric dimensions of the specimen involves a higher degree of inhomogeneity of rocks as regards the presence of discontinuities in specimens mass. An own calculation relationship of compressive breakage strength when the specimens cannot be performed to the diameter of 50 mm and for a slenderness ratio equal to 2, it is also proposed. [ABSTRACT FROM AUTHOR]

This study investigates the effects of environmental factors on tensile properties of laminated composites containing a central hole. Tensile tests were carried out on three types of specimens that are exposed to low temperature, room temperature and hydrothermal environment respectively. Tensile experiments were performed according to the ASTM D 5766. The results of moisture absorption tests indicated that the saturated moisture content of the specimens was around 0.7% after 1200 hours. Tensile tests results showed that the tensile strength, stiffness and fail strain of open hole increased with the content of 0° fiber, the tensile strength and stiffness increased in low temperature environment and decreased in hydrothermal environment. [ABSTRACT FROM AUTHOR]

One of the assumptions of Cotterell and Reddel's method of the essential work of fracture determination is the existence of a fracture process zone surrounded by an outer plastic zone extending to the whole ligament before crack initiation. To verify this hypothesis we developed a method based on micro hardness. The hardness values measured in the domain surrounding the tensile fracture area of ST-37-2 steel sheet D.E.N.T specimens confirm the existence of the two plastic zones. The extension of the plastic deformations to the whole ligament before the crack initiation and the circular shape of the outer plastic zone are revealed by the brittle coating method. [ABSTRACT FROM AUTHOR]

In order to study the operating life of structural components under the condition of load, the tensile damage experiments of carbon/epoxy composite are done in this paper. Then the mathematic model of the damage development of carbon/epoxy composite is built based on the experimental signal parameters, and then the reliability of carbon/epoxy composite is also discussed in this paper. Finally, the relationship between residual life of composite material and working-ours is deduced. [ABSTRACT FROM PUBLISHER]

The service life of a power transformer is governed by the condition of the insulating material. Due to deterioration of the transformer insulating material, the dielectric strength decreases and reduces the ability of the transformer to withstand Voltages. Novel hybrid insulation can be used in order to improve the mechanical strength apart from the dielectric property. The cellulose insulation is presently used in the power transformer which deteriorates over time and also affects the characteristics of the transformers. By improving the mechanical properties of insulation, the short circuit withstand strength of the power transformers can be improved. The high reliability and the long life of novel hybrid-insulation may result in cost savings [ABSTRACT FROM PUBLISHER]

The article discusses a study that introduces concepts of the strain-based design of pipelines. It explores the meaning of strain-based design, strain limits of the compressive and tensile strains, and the factors affecting strain limits as well as the empirical formulas to be used for calculating them. Factors influencing strain-based design are examined, such as strain aging, steel pipe requirements, and girth welding. Practices for strain-based design in China are also discussed.

The main purpose of this study is to develop low cost particleboards using durian skin as its reinforcing materials. Mechanical characterizations such as tensile, compressive and flexural strength were investigated. The fibers were extracted through the traditional retting and also mechanized process to compare the fibers production output. Surface topology study using Scanning Electron Microscope was done to examine the surface texture of the produced fibers, as shown in Figure 1. The experimental investigation reveals that the addition of these fibers reduces the mechanical properties of the composite specimen. However it can be concluded that this composite satisfies the basic requirement of non-load bearing construction materials, and they could be used for partition walls and the like. Thus, the potential for development, therefore, seems to be very promising. Finally, apart from saving energy consumption for the building, the proposed materials offer an alternative option to dispose waste of fruit industry. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the structural and mechanical properties of polyvinyl alcohol (PVA) thin film. The thin film surface morphology and functional group of PVA was characterized using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. SEM images show that the PVA thin film has a large smooth area, indicating formation of transparent film. The mechanical properties of the thin film were characterized by tensile tester and the hardness tester machines. The experimental results have shown that the PVA thin film has various potential applications and consistent with the available commercial polymer. [ABSTRACT FROM AUTHOR]

The tensile performances of coated membrane materials under uni-axial, bi-axial and multi-axial loading condition are very significant for the design, manufacture, installation and maintenance of lightweight membrane structures. This paper investigated and compared the tensile performance of coated membrane materials under uni-axial, bi-axial and multi-axial loading condition. The testing standards of uni-axial tensile tests were compared. Since there is none of standard about the bi-axial tensile tests, only the usual methods were listed. At last, all of the tensile tests of one kind of coated membrane material under uni-axial, bi-axial and multi-axial loading condition were carried out respectively on the multi-axial testing machine. The tensile performances under different loading condition were compared. It was found out that under bi- and multi-axial loading condition, the tensile performances are much better than those under uni-axial loading condition. These phenomena tell that due to the special structures (orthotropic and plain woven), the tensile performance of coated membrane materials is depending on the interactions of the warp yarns, the fill yarns and the coating material when loading under bi- and multi-axial conditions. Then, during the application of the coated membrane materials in lightweight structures, bi-axial or multi-axial loading conditions are necessary. [ABSTRACT FROM AUTHOR]

Mechanical low temperature investigations were carried out to determine the cryogenic mechanical properties of newly developed Fe-Cr-Mn alloys with contents of chromium between 5 % and 10 % and manganese between 30 % and 40 % under the Project G-811, Russia. The final products were forged, rolled, and solution heat treated to obtain appropriate plate sizes necessary for the mechanical measurements. The tensile properties of these alloys determined between 4 K and 7 K show for certain alloy combination high elongation values at fracture of greater than 50 % with considerable high yield strengths around 900 MPa. The measured fracture toughness values with small scale compact tension specimens using elastic plastic J-tests show KIC data between 100 MPa[Square_Root]m and 220 MPa[Square_Root]m according to the alloy combination. Fatigue crack growth rate (FCGR) measurements of these alloys result also in some alloy combination case, high resistance against crack propagation with measured Paris coefficients of m ∼ 5 and C ∼ 8.5 E-13 mm/cycle. Thermal expansion of these alloys has been also determined resulting in values between 1600 μm/m and 1700 μm/m expansion from 5 K to 290 K. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]