The deadliest accident ratio for cars and trucks on highways occurs when vehicles are running underneath trucks, causing serious and even fatal injuries to the occupants of the vehicle. When heavyweight trucks collide...
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The work intends to prepare a cotton/viscose fabric-reinforced hybrid composite (CVFRHC) using a compression moulding process using graphene as a filler material and investigate the mechanical characteristics of the c...
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The emergence of bioabsorbable implant materials has generated significant enthusiasm in medical and engineering research. The present systematic review study thoroughly examines the development, characteristics, uses...
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Despite the widespread use of Al7075-SiC composites in various engineering applications, their tribological performance remains a subject of interest due to challenges related to friction and wear. This study addresse...
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Two-wheeled self-balancing robot maintains balance and performs driving functions using two wheels, featuring excellent mobility due to its simple structure and wheel-driven system. However, when a long longitudinal s...
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The unconventional machining is an essential role in metal forming process. The dimensional accuracy and super finish are the main features of modern machining methods. Electric discharge machining is a competent proc...
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When a person makes a decision, it is automatically accompanied by a subjective probability judgment of the decision being correct, in other words, a confidence judgment. A better understanding of the mechanisms respo...
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Urban buses, particularly in large cities, are exposed to significant noise pollution. This paper presents a new family of materials at the micro/nano level designed for urban noise attenuation, specifically for appli...
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Challenge 3 of the 2022 NIST additive manufacturing benchmark(AM Bench)experiments asked modelers to submit predictions for solid cooling rate,liquid cooling rate,time above melt,and melt pool geometry for single and ...
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Challenge 3 of the 2022 NIST additive manufacturing benchmark(AM Bench)experiments asked modelers to submit predictions for solid cooling rate,liquid cooling rate,time above melt,and melt pool geometry for single and multiple track laser powder bed fusion process using moving *** in-house developed Additive Manufacturing Computational Fluid Dynamics code(AM-CFD)combined with a cylindrical heat source is implemented to accurately predict these *** heat source calibration is proposed relating volumetric energy density(ψ)based on experiments available in the *** parameters of the heat source of the computational model are initially calibrated based on a Higher Order Proper Generalized Decomposition-(HOPGD)based surrogate *** prediction using the calibrated heat source agrees quantitatively with NIST measurements for different process conditions(laser spot diameter,laser power,and scan speed).A scaling law based on keyhole formation is also utilized in calibrating the parameters of the cylindrical heat source and predicting the challenge *** addition,an improvement on the heat source model is proposed to relate the Volumetric Energy Density(VED_(σ))to the melt pool aspect *** model shows further improvement in the prediction of the experimental measurements for the melt pool,including cases at higher VED_(σ).Overall,it is concluded that the appropriate selection of laser heat source parameterization scheme along with the heat source model is crucial in the accurate prediction of melt pool geometry and thermal measurements while bypassing the expensive computational simulations that consider increased physics equations.
In this study, high velocity impact behaviour of friction stir welded AA7075-T651 25 mm thick plates were investigated using a 7.62 mm × 51 mm lead core and 7.62 mm × 39 mm steel core projectiles. Prior to b...
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In this study, high velocity impact behaviour of friction stir welded AA7075-T651 25 mm thick plates were investigated using a 7.62 mm × 51 mm lead core and 7.62 mm × 39 mm steel core projectiles. Prior to ballistic trails, mechanical and metallurgical properties of friction stir welded AA 7075-T651 25 mm thick plates were studied. Microstructural and hardness studies revealed that friction stir welds constituted three distinct regions namely Weld Nugget(WN), Thermo-mechanically Affected Zone(TMAZ) and Heat Affected Zone(HAZ). Base Material(BM) and all three weld regions were ballistically tested as per military standard NIJ.0108.01 using lead and steel core bullets at maximum permissible velocities of 830 ± 20 and 700 ± 30 m/s, respectively. It has been found that base material(AA7075-T651)and all three weld regions of 25 mm thick plates were able to resist perforation by both types of projectiles used. However depth of penetration has been found to increase from BM to WN, HAZ and TMAZ for both types of projectiles. In all cases steel core projectiles caused higher depth of penetration compared to those caused by lead core projectiles. TMAZs of the friction stir welds were found to be the weakest zone. The fracture that occurred in the base material was spall fragmentation indicating brittle failure, whereas all zones of friction stir welded AA7075-T651 targets with a front petalling, indicating ductile failure. The post-ballistic tested samples showed no significant change in the microstructure of the BM and WN. On the other hand, TMAZ and HAZ showed severe grain deformation in the direction of projectile penetration, and the formation of adiabatic shear bands(ASB). This work showed that 25 mm thick friction stir welded AA7075-T651 joints responded well to ballistic impact loads, making them a good choice for light combat vehicles.
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