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11 – 20 of over 1000Eujin Pei, Giselle Hsiang Loh, David Harrison, Henrique de Amorim Almeida, Mario Domingo Monzón Verona and Rubén Paz
The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single material, and 4D…
Abstract
Purpose
The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single material, and 4D printing of multiple materials. It is proposed that 4D printing can be achieved through the use of functionally graded materials (FGMs) that involve gradational mixing of materials and are produced using an additive manufacturing (AM) technique to achieve a single component.
Design/methodology/approach
The latest state-of-the-art literature was extensively reviewed, covering aspects of materials, processes, computer-aided design (CAD), applications and made recommendations for future work.
Findings
This paper clarifies that functionally graded additive manufacturing (FGAM) is defined as a single AM process that includes the gradational mixing of materials to fabricate freeform geometries with variable properties within one component. The paper also covers aspects of materials, processes, CAD, applications and makes recommendations for future work.
Research limitations/implications
This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process involving gradational mixing of materials to fabricate freeform geometries with variable properties within one component. FGAM requires better computational tools for modelling, simulation and fabrication because current CAD systems are incapable of supporting the FGAM workflow.
Practical implications
It is also identified that other factors, such as strength, type of materials, etc., must be taken into account when selecting an appropriate process for FGAM. More research needs to be conducted on improving the performance of FGAM processes through extensive characterisation of FGMs to generate a comprehensive database and to develop a predictive model for proper process control. It is expected that future work will focus on both material characterisation as well as seamless FGAM control processes.
Originality/value
This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process that includes gradational mixing of materials to fabricate freeform geometries with variable properties within one component.
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Sanjay Kumar Singh, Lakshman Sondhi, Rakesh Kumar Sahu and Royal Madan
The purpose of the study is to perform elastic stress and deformation analysis of a functionally graded hollow disk under different conditions (rotation, gravity, internal…
Abstract
Purpose
The purpose of the study is to perform elastic stress and deformation analysis of a functionally graded hollow disk under different conditions (rotation, gravity, internal pressure, temperature with variable heat generation) and their combinations.
Design/methodology/approach
The classical method of solution, Navier's equation, is used to solve the governing equation. The analysis considers thermal and mechanical boundary conditions and takes into account the variation of material properties according to a power law function of the radius of the disk and grading parameter.
Findings
The findings of the study reveal distinct trends and behaviors based on different grading parameters. The influence of gravity is found to be negligible, resulting in similar patterns to the pure rotation case. Variable heat generation introduces non-linear temperature profiles and higher displacements, with stress values influenced by grading parameters.
Practical implications
The study provides valuable insights into the behavior of displacement and stresses in hollow disks, offering a deeper understanding of their mechanical response under varying conditions. These insights can be useful in the design and analysis of functionally graded hollow disks in various engineering applications.
Originality/value
The originality and value of this study lies in the consideration of various loading combinations of rotation, gravity, internal pressure and temperature with variable heat generation. Furthermore, the study of effect of various angular rotations, temperatures and pressures expands the understanding of the mechanical behavior of such structures, contributing to the existing body of knowledge in the field.
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Hongyan Tian, Jianbing Sang, Rihan Ao and Shujun Hou
As a good absorbing material candidate, a functionally graded wave absorber can be tailored to satisfy the impedance match principle by gradually changing material property. The…
Abstract
Purpose
As a good absorbing material candidate, a functionally graded wave absorber can be tailored to satisfy the impedance match principle by gradually changing material property. The paper aims to discuss these issues.
Design/methodology/approach
The electromagnetic wave absorption properties are discussed. An analysis model is proposed to provide an insight into its mechanical characteristics during wave absorption. Considering the energy-converting and thermal deformation properties, the thermoelastic behaviors of an absorber are analyzed by numerical method. The effects of material and geometrical properties are discussed in detail.
Findings
The results demonstrate that absorbing effect of graded composite is enhanced. Good performance of low reflectance and high absorption with gentle thermal stress distribution can be obtained by proper designing of the gradient absorber.
Originality/value
Functionally graded materials exhibit a progressive compositional gradient change along certain dimension of structures, which can be used as absorbing materials for the gradual change of material property tailored to satisfy the principle of impedance match. The design of functionally graded absorbing materials usually should consider not only the electromagnetic performance, but also the mechanical properties simultaneously. Therefore, few investigations have addressed the mechanical characteristics of absorbers. This paper presents some studies on the electromagnetic, especially mechanical behaviors during electromagnetic wave absorption. It is helpful to provide mechanical reference for designing an absorber.
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Bo Chen, Tao Wang, Xin Xi, Caiwang Tan and Xiaoguo Song
Ti-Al composite plates have been used in aerospace and other important fields for specific purposes in recent years. However, relatively few studies have concentrated on Ti-Al…
Abstract
Purpose
Ti-Al composite plates have been used in aerospace and other important fields for specific purposes in recent years. However, relatively few studies have concentrated on Ti-Al additive manufacturing because during additive manufacturing process the local fusion and mixing of Ti/Al are inevitable. These areas where Ti and Al are mixed locally, especially interface, could easily generate high residual stresses and cracks. This study aims to manufacture Ti-Al functionally graded material and investigate the interaction of interface.
Design/methodology/approach
In this study, Ti6Al4V/AlSi10Mg functionally graded materials were fabricated by laser based directed energy deposition (L-DED) and a strategy using V interlayer to relieve interfacial stress was investigated.
Findings
The area between the two materials was divided into transition zone (TZ) and remelting zone (RZ). The phase distribution, microstructure and micro-Vickers hardness of the TZ and RZ were investigated. Typical intermetallic compounds (IMCs) such as TiAl3, Ti3Al and Ti5Si3 were found in both composites. The addition of V interlayer promoted the homogenization of IMCs near interface and led to the formation of new phases like V5Si3 and Al3V.
Originality/value
The solidification process near the interface of Ti-Al functionally graded material and the possible generation of different phases were described. The result of this paper proved the feasibility of manufacturing Ti-Al functionally graded material by L-DED.
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Upendra Bajpai, Palash Soni, Vivek Kumar Gaba and Shubhankar Bhowmick
When the temperature of an air conditioning unit’s fin surface goes below its dew point temperature, condensation forms on the unit’s surface. As a result, the cooling coil’s…
Abstract
Purpose
When the temperature of an air conditioning unit’s fin surface goes below its dew point temperature, condensation forms on the unit’s surface. As a result, the cooling coil’s performance is compromised. By altering the cross-section and heat conductivity of the fins, the performance of such systems can be improved. This study aims to analyze the thermal performance of longitudinal fins made up of a variable thickness (assuming constant weight) and functionally graded material.
Design/methodology/approach
Different grading parameters are considered for an exponential variation of thermal conductivity. The humidity ratio and the corresponding fin temperatures are assumed to follow a cubic relationship. The Bvp4c solver in MATLAB® is used to solve the differential heat transfer equation resulting from balancing heat transfer in a small segment.
Findings
Validation of the methodology is provided by previous research presented in this area. For different combinations of grading parameters, geometry parameters and relative humidity, the normalized temperature distribution along the fin length and fin efficiency contours are plotted, and the results are very promising.
Originality/value
When compared to the efficiency of an isotropic homogenous rectangular longitudinal fin with optimal geometry and grading parameters, a 17% increase in efficiency under fully wet conditions is measured. When it comes to fin design, these efficiency contour plots are extremely useful.
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Royal Madan and Shubhankar Bhowmick
Functionally graded materials are a special class of composites in which material are graded either continuously or layered wise depending upon its applications. With such…
Abstract
Purpose
Functionally graded materials are a special class of composites in which material are graded either continuously or layered wise depending upon its applications. With such variations of materials, the properties of structure vary either lengthwise or thickness wise. This paper aims to investigate models for effective estimation of material properties, as it is necessary for industries to identify the properties of composites or functionally graded materials (FGM’s) before manufacturing and also to develop novel material combinations.
Design/methodology/approach
Available models were compared for different material combinations and tested with experimental data for properties such as Young’s modulus, density, coefficient of thermal expansion (CTE) and thermal conductivity. Combinations of metal–ceramic and metal–metal were selected such that their ratios cover a wide range of materials.
Findings
This study reveals different models will be required depending on the material used and properties to be identified.
Practical implications
The results of the present work will help researchers in the effective modeling of composites or FGM’s for any analysis.
Originality/value
This paper presents a comparison and review of various analytical methods with experimental data graphically to find out the best suitable method. For the first time, the Halpin-Tsai model was extended in the analysis of the CTE which shows good approximations.
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Mehdi Soodi, Syed H. Masood and Milan Brandt
This paper aims to investigate the changes in tensile properties of novel functionally graded materials (FGMs) and wafer structures created by direct metal deposition (DMD…
Abstract
Purpose
This paper aims to investigate the changes in tensile properties of novel functionally graded materials (FGMs) and wafer structures created by direct metal deposition (DMD) additive manufacturing (AM) technology.
Design/methodology/approach
Laser-assisted DMD was used to create two innovative sets of metallic structures – the functionally graded and wafer-layered structures – using pairs of six different engineering alloys in different combinations. These alloys were selected due to their high popularity within a diverse range of industries and engineering applications. The laser-assisted DMD was selected as a suitable technique to create these complex structures because of its capability to deposit more than one alloy powder at a time. After creation of these structures, their tensile strength was tested in a series of tensile tests and the results were compared with those of single alloy samples.
Findings
It was observed that the mechanical properties of FGMs and wafer structure samples were clearly different from those of the single alloy samples, a fact which creates a whole pool of opportunities for development of new materials or structures with desired mechanical properties that cannot be achieved in single alloy parts.
Originality/value
The study demonstrates the application of the DMD process to produce unique structures and materials, which would be high in demand in engineering applications, where metallic parts are exposed to high loads and where excessive tensile stresses may adversely affect the performance of such parts.
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Supen Kumar Sah and Anup Ghosh
The purpose of this paper is to carry out free vibration and buckling analysis of functionally graded material (FGM) plate.
Abstract
Purpose
The purpose of this paper is to carry out free vibration and buckling analysis of functionally graded material (FGM) plate.
Design/methodology/approach
Equilibrium and stability equations of FGM rectangular plate under different boundary conditions are derived using finite element method-based inverse trigonometric shear deformation theory (ITSDT). Eight-noded rectangular plate element with seven degrees of freedom at each node is used for the present analysis. The power-law distribution method has been considered for the continuously graded variation in composition of the ceramic and metal phases across the thickness of a functionally graded plate.
Findings
The finite element formulation incorporated with ITSDT and provisions of the constitutive model of FGM plate has been implemented in a numerical code to obtain the natural frequency and critical buckling load under uniaxial and biaxial compressive load. The influence of material gradation, volume fraction index, span to thickness ratio and boundary constraints over free vibration and buckling response has been studied.
Originality/value
Development and validation of finite element methodology using ITSDT to predict the structural response of the FGM plates under different loading, geometric and boundary conditions.
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This study aims to investigate the production and abrasive wear rate of functionally graded TiB2/Al composites. TiB2 particles have been spontaneously formed in liquid matrix…
Abstract
Purpose
This study aims to investigate the production and abrasive wear rate of functionally graded TiB2/Al composites. TiB2 particles have been spontaneously formed in liquid matrix using in situ technique. The properties of composites such as hardness, abrasive wear rate and microstructure have been examined.
Design/methodology/approach
In situ TiB2 reinforcement phase was synthesized by using a liquid Al–Ti–B system. A semi-solid composite (Al(l)-TiB2(s)) prepared at 900°C was solidified under a centrifugal force to both grade functionally and give the final shape to materials. Abrasive wear test of materials was conducted using the pin-on-disk method at room temperature. The wear tests were carried out with two different loads of 1 Newton (N) and 2 N, a sliding velocity of 3.5 m s−1 and a sliding distance of 75 m.
Findings
This research provided the following findings; TiB2 particles can be successfully synthesized with in situ reaction technique in molten aluminum. It was determined that abrasive wear rate increases with increasing load and decreases with increasing TiB2 reinforcement content within matrix.
Originality/value
In previous studies, there have been many trials on the in situ production of TiB2-reinforced aluminum matrix composites. However, there are few studies on production of in situ TiB2-reinforced aluminum matrix functionally graded materials. At the same time, there is no study that the properties of composite, such as hardness and abrasive wear rate, are examined together according to centrifugal force.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0538/
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Mehmet Eker, Durmuş Yarımpabuç and Kerimcan Çelebi
This paper aims to present thermal and mechanical stresses in solid and hollow thick-walled cylinders and spheres made of functionally graded materials (FGMs) under the effect of…
Abstract
Purpose
This paper aims to present thermal and mechanical stresses in solid and hollow thick-walled cylinders and spheres made of functionally graded materials (FGMs) under the effect of heat generation.
Design/methodology/approach
Constant internal temperature and convective external conditions in hollow bodies along with internal heat generation with a combination of outer convective conditions in solid bodies are investigated individually. The effect of the heat convection coefficient on solid bodies is additionally discussed. The variation of the FGM properties in the radial direction is adapted to the Mori–Tanaka homogenization schemes, which produces irregular and two-point linear boundary value problems that are numerically solved by the pseudospectral Chebyshev method.
Findings
It has been shown that the selection of the mixtures of FGMs has to be made correctly to keep the thermal and mechanical loads acting on objects at low levels.
Originality/value
In this study, both solid and hollow functionally graded cylinders and spheres for different boundary conditions that are as their engineering applications are examined with the proposed method. The results have demonstrated that the pseudospectral Chebyshev method has high accuracy, low calculation costs and ease of application and can be easily adapted to such engineering problems.
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