Papers by Keyword: Impact Test

Abstract: In the present study, a quasi-static compression test and impact test are carried out on a Polycarbonate plate with thickness of 2.66 mm and an effective diameter of 205 mm. The impact test is carried out on a pneumatic gun using a hardened truncated cone projectile of mass 25.8 g at different velocities. On the other hand, a servo mechanical universal testing machine with a 50 kN capacity is used to carry out the quasi-static compression test at a speed of 2 mm/min adopting an indenter of truncated nose shape. The Dynamic Enhancement Factor, or DEF, is computed as the ratio of quasi-static perforation energy to impact perforation energy. The measured DEF in the present study is compared with previously published results for metal and polycarbonate. Also local deformation of the plate after perforation is compared for both quasi-static test and dynamic test.

Abstract: Environmental issues over the eventual fate of post-consumer polymers can be dealt with in two separate ways which is recycling or using biodegradable polymers. However, it is evident that recycling polymers from post-consumer polymers can decrease the mechanical properties over time. Hence, to strengthen the recycled polymers, integrating fibers, such as luffa, into the High-Density Polyethylene (HDPE) matrix, was carried out to produce a fiber reinforced recycled polymer (FRrP) composite. The tensile testing of the FRrP composite shows that the 10% fiber volume fraction (FVF) composite exhibits a higher tensile strength of 3.9% than the neat recycled HDPE (RHDPE). In terms of Young’s Modulus, the 5% FVF of FRrP is shown to have a higher value than the neat RHDPE by 54%. The low density of luffa fibers also contributes to the composites lightweight character. The impact testing shows that the FRrP enhances the impact properties when compared to the neat RHDPE. The peak load, perforation energy, and the total energy absorbed by the FRrP indicate an increasing trend when luffa, of up to 15% FVF, is added as the reinforcement. Thus, the addition of luffa as reinforcement in RHDPE shows significant potential as a high-performance, sustainable, and environmentally friendly material, such as automotive parts and protective gear.

Abstract: The AA2014/SiC/Gr hybrid metal matrix composites are developed with addition of 0.5% to 1.5% SiC particles (weight fraction) in 0.5% weight fraction interval and the graphite (Gr) is 1% weight fraction constant for all composites were prepared by stir casting method. The effects of SiC and Gr on the microstructural and mechanical properties of the base cast and hybrid composites were studied by SEM, hardness, and impact tests. The results indicate that mechanical properties of the aluminium hybrid metal matrix composites (AHMMCs) change according to their increment of SiC and Gr particle. The hardness and impact strength of base cast and hybrid composites increased during the addition of SiC and Gr particle. The hardness and impact strength of base cast and hybrid composites increased during the addition of SiC and Gr particle. The maximum hardness is observed in the fourth sample with 1% Gr and 1.5% SiC with 7% increment which is 102.4 VHN. The high impact strength was observed for base alloy of 24% than hybrid composite. The composite of 1% SiC and 1% Gr is given less wear loss and coefficient of friction. The Corrosion resistance is better in the composite of 0.5% SiC and 1% Gr and the optical micrographs shows that the composite with 0.5% SiC and 1% Gr shows good texture.

Abstract: The insertion of bainite as a total or partial substitute for martensite is a promising option concerning the combination of high strength and toughness, properties mainly sought after by the aerospace and high technology industries. High-carbon, carbide-free bainitic steels are obtained through thermomechanical processing, with a final microstructure consisting of bainitic ferrite and retained austenite. The presence of carbides in these steels can reduce fracture toughness when compared to conventional quenched and tempered steels. This article aims to correlate the microstructure and impact resistance of four high carbon steel alloys with varying contents of Nickel, Silicon, and Manganese, which were austenitized at 870 °C and austempered at 280 °C at 12-hour intervals, 24 hours, 72 hours, and 168 hours. Thus, the microstructural characteristics, their morphological and kinetic aspects were determined, evaluating the mechanical properties from Rockwell C hardness tests, where commonly in the four alloys there is a decrease in the hardness values, due to the stress relief that occurred during the treatment of austempered, causing the bainitic microstructure to have larger lath shapes, causing a drop in hardness values in the impact test. For the fractographic analysis of the samples using scanning electron microscopy (SEM), the analyses showed three stages of the phase transformation: martensitic microstructure; multiphase microstructure composed of bainitic ferrite, martensite, and retained austenite; microstructure formed by bainitic ferrite and retained austenite, due to the stasis of the bainitic reaction. The alloys obtained lower rates of energy absorption in the initial times (from 24 hours) due to the instability of the austenite which consequently generated an increase in the energy absorption capacity, obtained from the energy dissipated by the impact of the Charpy test the effect called plasticity. Transformation-induced (TRIP) phenomenon causing when austenite becomes martensite, thus favoring increased ductility. Finally, it was observed that alloy (a), with lower content (%) of nickel, has a predominance of brittle fracture, as a microcleavage mechanism resulting from a combined action of a failure micromechanism. For alloy (c) with higher nickel content (%), the predominant fracture is also of the brittle type, with the presence of small microcavities common to the alveoli. The other important point to be considered is the influence of the treatment time, which does not interfere in the failure mechanism, remaining fragile until the end for alloy (a), alloy (b), and alloy (c).

Abstract: The natural fibers are the alternative to glass and other human-made fibers, because of their low cost and readily available from natural resources and acts as a reinforcing material for the polymer composites. Jute is the most widely used natural fibers among the various fibers due to its superior characteristics. Composite materials are made with different materials that are physically and chemically different alienated by interfaces. In this work, epoxy and polyester hybrid composites reinforced with jute and glass fiber were fabricated by hydraulic press method and their tensile and impact properties were compared. The mechanical properties of jute/glass hybrid composites with different layers such as tensile strength, percentage of elongation and impact strength were evaluated using ASTM specifications. Tensile and Charpy impact test results indicated that jute/glass fiber reinforced epoxy composites have shown optimum properties than polyester composites.

Abstract: The effect of the addition of submicron glass fibers into the matrix of curved thin shell of CFRP in thickness direction on the energy absorption during out-of-plane impact was investigated with four types of specimens. Four types of CFRP shells were prepared in which each shape was: (a) flat plate (b) half-cylinder (c) low wide elliptical half-cylinder (d) high wide elliptical half-cylinder. The results showed that improvement of impact energy absorption was obtained for thin shell specimen with curved geometry as well as that for flat plate by adding submicron glass fiber into the matrix. This study found that design with half-cylinder CFRP shell is rather effective to utilize the result of modification with submicron glass fibers previously added into the matrix where the impact energy absorption was improved.

Abstract: Composite material referred to build speed boats with a lightweight and also endured to support a crushing load. To design and analyze speed boats to support a collision accident, the composite material would be implemented into finite element model. This research had proposed the material model of a fiberglass composite material which used to construct speed boats in Pattaya, Thailand. The rectangular plate of composite material was analyzed according to the drop weight impact test. The orthotropic and isotropic material models were applied to define material properties of the finite element model of the fiberglass plate. The finite element analysis (FEA) results were compared with experimental data. The FEA with isotropic material for modeling the fiberglass material results were in good agreement with experiment. There was an average difference of 0.4195 J when compared the residual energy with the experimental data. Consequently, this fiberglass material model would be used to analyze the speed boat collision in a further work.

Abstract: The aim of the present work was to study the mechanical properties of thin nanocomposite Mo-B-C coatings consisting of nanocrystalline Mo₂BC embedded in amorphous Mo-B-C matrix. Magnetron sputtering of three targets, B₄C, C and Mo, was used for coatings preparation. The Mo-B-C coatings were deposited on high speed steel substrates. The fracture resistance of Mo-B-C coatings was studied by both indentation and dynamic impact tests. The impact tests enabled us to predict the load limit causing the coating destruction.

Abstract: The structure of the heat resistant 12Cr1MoV steel modified by Zr⁺ ion beam treatment was investigated by optical, scanning electron and transmission electron microscopy as well as X-ray diffraction methods. It was shown that the modification occurs over the entire cross section of the irradiated specimen with thickness of 1 mm. Changes in mechanical properties under static, cyclic and dynamic loading of the specimens after the treatment are interpreted in term of structural modifications.

Abstract: This paper studies the mechanical properties of the aramid fiber reinforced epoxy resin composite by varying the percentage composition. Three different compositions of aramid fiber are 30 %, 35 % and 45 % by weight. The aramid epoxy composite was manufactured by the vacuum suction method. The manufactured composites are then cured by the hot air oven for 180 minutes. The prepared composites undergo through various tests such as the tensile test, hardness test and impact test. The results of the tests on the three compositions analyzed and variation in its mechanical properties is noted.