Article of the Year 2020
Calculation and Estimation of Surface Roughness and Energy Consumption in Milling of 6061 AlloyRead the full article
Advances in Materials Science and Engineering publishes research in all areas of materials science and engineering, including the synthesis and properties of materials, and their applications in engineering applications.
Chief Editor, Amit Bandyopadhyay, is based at Washington State University and is interested in the fields of additive manufacturing or 3D printing of advanced materials. His current research is focused on metal additive manufacturing, biomedical devices and multi‑materials structures.
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Effect of Hemp Fibre Surface Treatment on the Fibre-Matrix Interface and the Influence of Cellulose, Hemicellulose, and Lignin Contents on Composite Strength Properties
Natural fibres have recently become an attractive alternative to synthetic fibres in the implementation of polymer composite structures. Inherent flaws within natural fibres in terms of their constituent contents (hemicellulose, cellulose, and lignin) reduce the compatibility of these fibres with polymer matrices. In this study, the effects of chemical treatments on hemp fibres and the resulted polyester matrix composite are investigated. The fibres were treated with alkali (0–10% NaOH), acetyl, and silane chemicals. Long unidirectional fibre composites were prepared by vacuum-assisted resin transfer moulding (VARTM) process. Thermal properties of the fibres were tested using differential scanning calorimetry (DSC) analyses. The mechanical properties of the composite samples were tested using compression and bending tests. Failure analysis of tested composites was undertaken through Optical Microscope (OM) and Scanning Electron Microscope (SEM). The results showed that the treatments of the 4% NaOH reduced interfacial bonding strength and decreased composite properties compared to untreated samples. At higher concentrations (6–10% NaOH), the mechanical properties of the composites increased as a result of greater interfacial bonding. Different trends were observed in the case of alkalised fibres that were further treated with acetyl and silane treatments. It was observed that the treated fibres effectively improved the bonding properties of composites and was in agreement with the micrographs.
Experimental Study on the Impact Resistance of Closed-Cell Aluminum Foam Protective Materials to RC Piers under Lateral Impact
In this study, the lateral impact tests of six RC piers which were protected by closed-cell aluminum foam (CCAF) were carried out by making use of an ultrahigh drop hammer horizontal impact test system. The protective effects of CCAF with different densities on the piers were then analyzed. The data regarding the piers’ impact force, displacement, reinforcement strain, and crack and damage development were mainly collected during the experimental testing processes. The results indicated that, when the impact energy was less than 7258 J and the density of the CCAF was 0.45 g/cm3, the cumulative impact force and displacements of the piers decreased by 67% and 35%, respectively. Therefore, it was considered that the CCAF with a density of 0.45 g/cm3 had displayed the best protective effects at that stage. It was also observed that when the impact energy was greater than 7258 J and the density of the CCAF was 0.55 g/cm3, the cumulative impact force and displacements of the piers decreased by 25% and 18%, respectively. Therefore, the CCAF with a density of 0.55 g/cm3 had displayed the best protective effects at that stage. Furthermore, under the conditions of constant accumulative impact energy, the protective effects of CCAF on the piers were observed to be weakened if it entered the densification stage too early and high-yield platforms were formed due to the density levels becoming too high. However, it was found that reasonable density and thickness increases could effectively delay the entry of CCAF into the densification stage, which effectively reduced the shearing effects which occurred when the impact speeds were too high, thereby preventing the shear failure of the piers.
Statistical Modelling to Study the Implications of Coated Tools for Machining AA 2014 Using Grey Taguchi-Based Response Surface Methodology
Milling is the surface machining process by removing material from the raw stock using revolving cutters. This process accounts for a major stake in most of the Original Equipment Manufacturing (OEM) industries. This paper discusses optimizing process parameters for machining the AA 2014 T 651 using a vertical milling machine with coated cutting tools. The process parameters such as cutting speed, depth of cut, and type of the cutting tool with all its levels are identified from the previous literature study and several trial experiments. The Taguchi L9 Orthogonal Array (OA) is used for the experimental order with the chosen input parameters. The commonly used cutting tools in the machining industry, such as High-Speed Steel (HSS) and its coated tools, are considered in this study. These tools are coated with Titanium Nitride (TiN) and Titanium Aluminum Nitride (TiAlN) by Physical Vapor Deposition (PVD) technique. The output responses such as cutting forces along the three-axis are measured using a milling tool dynamometer for the corresponding input factors. The input process parameters are optimized by considering the output responses such as MRR, machining torque, and thrust force. Grey Taguchi-based Response Surface Methodology (GTRSM) is used for multiobjective multiresponse optimization problems to find the optimum input process parameter combination for the desired response. Polynomial regression equations are generated to understand the mathematical relation between the input factor and output responses as well as Grey Relational Grade (GRG) values. The optimum process parameter combination from the desirability analysis is the HSS tool coated with TiAlN at a cutting speed of 270 rpm and a depth of cut value of 0.2 mm.
Performance of Cracked Ultra-High-Performance Fiber-Reinforced Concrete Exposed to Dry-Wet Cycles of Chlorides
This paper presents an experimental study on the performance of cracked ultra-high-performance fiber-reinforced concrete (UHPC) exposed to dry-wet cycles of 3.5% NaCl solution under the temperature of 60°C. The results show that the wider the crack, the higher the corrosion degree of steel fibers embedded in UHPC, and the deeper the chloride ion diffusion on both sides of the crack. With the increase of dry-wet cycles, the flexural strength of precracked UHPC first decreases and then increases, and the lowest flexural strength was observed in 60 dry-wet cycles. Although self-healing is hard to cease the corrosion of steel fibers, it can relieve the corrosion of steel fibers and improve the flexural strength exposed to 100 dry-wet cycles.
Study on the Rock Fracture during Fluid Injection Using a Coupled Flow-Stress-Damage (FSD) Model: Insight into the Stress Shadow Effect
In order to investigate the influence of pore pressure on hydraulic fracturing behavior in the local and whole model, the coupled flow-stress-damage (FSD) analysis system RFPA-Flow was used to study the influence of rock heterogeneity, natural stress ratio, double-hole spacing, and water pressure gradient on the stress shadow effect. The numerical results show that the tensile crack induced by pore water pressure is significantly affected by the pore water pressure and water pressure gradient. The larger the pore pressure gradient is, the more asymmetrical the crack development pattern and the smaller the instability pressure of the model. In addition, the shape of hydraulic fracture becomes much more irregular with the increase in rock heterogeneity. The number and shape of tip microcracks under the influence of local water pressure are closely related to the homogeneity of rock. Moreover, when the natural stress difference is large, the hydraulic fracture propagates parallel to the maximum principal stress; when the stress field is close and the spacing between two holes is less than 5 times the diameter, the propagation direction of hydraulic fractures between holes is perpendicular to the maximum principal stress. It is found that no hydraulic fractures occur between the two holes when the distance between holes is greater than 5 times the diameter.
The Ontology-Based Approach Supporting Holistic Energy-Tunnel Design considering Cost, Heat Flux, and System Feasibility
As an emerging geothermal structure, the energy tunnel has been an important part of geothermal engineering. However, the conventional methods for designing energy tunnels mostly rely on complex numerical models. Furthermore, a macrolevel multidomain collaborative design method to consider multiple areas and design indicators is unavailable. This study combined ontology and semantic Web rule language to establish the domain knowledge of energy tunnels which is an enrichment of the conventional ground source heat pump domain knowledge and develop a comprehensive decision-making tool named OntoETS for the design of energy-tunnel systems. The tool can promote the optimal design scheme with an optimal combination of multiple indexes through an analysis of the economy, heat flux, and system feasibility of the energy-tunnel system from a macroperspective by combining multiple domains. Furthermore, a case study was conducted to demonstrate the effectiveness and practicability of the developed holistic decision-making system.