Properties Of Multilayer Materials Research Articles

Preparation and sound absorption properties of multi-layer composites formed by waste polyphenylene sulfide filters

Composite materials with multi-layer structure were prepared by combining polyurethane film and waste polyphenylene sulfide filters by hot melting, which could be used as sound-absorbing materials to contribute to the noise control and reutilization of industrial waste. The structure, mechanical property, pore size distribution and stability of waste polyphenylene sulfide filters were investigated and could directly affect the quality of recycled products. The effects of layer numbers, layering sequence and polyurethane film thickness on sound absorption and insulation properties were also analyzed using an impedance tube absorption test system. The results showed that multi-layer materials had a better sound absorption effect than single-layer polyphenylene sulfide filters at low frequency. The sound absorption coefficients of the single-layer sample was only 0.081 at 1000 Hz, while the sound absorption coefficients of the five-layer sample could reach 0.26. The sound absorption properties of multi-layer materials were slightly affected by layering sequence, but polyurethane film thickness had a significant effect on sound absorption properties. The α of the SUS1 and USU1 samples were 0.151 and 0.170, while the α of the SUS3 and USU3 samples were only 0.076 and 0.056, respectively. Meanwhile, the sound insulation properties of multi-layer materials could be significantly influenced by the polyurethane film position. The sound transmission loss of the SUSUSU3 sample was just 32.83 dB, whereas that of the USUSU3 sample could reach 47.94 dB. Moreover, when polyurethane film was located on the sound facing side of multi-layer materials, the increase in polyurethane film thickness could cause the average sound reduction index of the USUSU sample to increase from 28.76 dB to 47.94 dB.

Inverse Estimation of Effective Thermal Conductivity of Multilayer Materials Considering Thermal Contact Resistance

Abstract Multilayer materials have been widely used in engineering applications, attributed to excellent thermo-mechanical performances. However, the thermal or mechanical properties of multilayer materials remain elusive, owing to contact behaviors etc. factors. In order to address this issue, an innovative method is employed to estimate the effective thermal conductivity (ETC) of multilayer materials considering thermal contact resistance (TCR) between layers, and the equivalence performance is investigated by solving three-dimensional inverse heat conduction problems. First, the equivalence method is validated by available experimental data of a multilayered insulation composite material. Then, the precision of different equivalence methods is compared, and the results indicate that the anisotropic equivalence method has higher accuracy than the isotropic and orthotropic equivalences for the five-layer material in the present work. Finally, the robustness and stability of the anisotropic equivalence method are evaluated in detail. The present work provides a new alternative method for predicting the effective thermal conductivity of multilayer materials.

Non-invasive study to determine changes in physical properties of multilayer materials

Non-invasive study to determine changes in physical properties of multilayer materials

Microstructures and mechanical properties of multi-layered materials composed of Ti-6Al-4V, vanadium, and 17–4PH stainless steel produced by directed energy deposition

The joining of dissimilar Ti alloy and stainless steel (SS) is challenging but necessary for the extensive applications of Ti alloy/SS hybrid materials. Consequently, joints formed by the sequential laser deposition of V and 17–4PH SS on Ti-6Al-4V and V and Ti-6Al-4V on 17–4PH SS were investigated. The effect of the laser power (150, 180, 210, and 300 W) on the properties of the joints was also investigated to determine the optimal conditions for the deposition of the V interlayer. The microstructures and mechanical properties of the joints were compared with those of similar Ti-6Al-4V/V/17–4PH SS joints produced by welding. The joints produced on Ti-6Al-4V substrates using laser powers of 180 (VTi180) and 210 W (VTi210) were crack-free and consisted mainly of body-centered cubic phases throughout their Ti-6Al-4V/V/17–4PH SS microstructures. The joints produced on 17–4PH SS substrates using laser powers of 180 (VFe180) and 210 W (VFe210) had regions with cracks near their 17–4PH SS/V interfaces, owing to the presence of the brittle Fe–V σ phase. The joints produced with V deposited using a low laser power of 150 W or a high laser power of 300 W delaminated. The tensile strengths of VTi180, VTi210, VFe180, and VFe210 were 575, 700, 520, and 470 MPa, respectively, markedly exceeding those of most similar reported welded joints. Narrow fusion zones, negligible heat-affected zones, and the presence of compositionally graded interlayers that cause interlayer strengthening accounted for the high strengths of the additively manufactured joints. The comparatively high Ti content of the V interlayer of the VTi210 joint accounted for its extraordinary tensile strength (700 MPa) and relatively high hardness. The lower strengths of VFe180 and VFe210 were attributed to the presence of brittle interlayer regions formed by the incorporation of Fe. Therefore, the use of V in the Fe-V-Ti sequence is not recommended. • Compositionally graded structure could be obtained throughout the V interlayer. • Joints of VTi180 and VTi210 are crack free with mainly BCC phases. • Joints of VFe180 and VFe210 contain cracks due to Fe–V σ phases at interfaces. • AM process can produce a sample with a relatively large size of 90 × 40 × 7 mm 3 .

Enhanced energy storage performance of all-organic sandwich structured dielectrics with FPE and P(VDF-HFP)

Rational design of multilayer structures can greatly improve the breakdown strength and is thus an effective method to improve the energy density of all-organic polymers. In this paper, a simple hot-pressing method was used to combine P(VDF-HFP) with FPE to prepare an all-organic multi-layered composite film with a symmetric structure. The effects of the sandwich structure on the breakdown strength, dielectric properties, and energy storage properties of multilayer materials were investigated in depth. Compared with the single-layer P(VDF-HFP), the FPE on both sides of the composite significantly enhanced the breakdown strength and inhibited the dielectric loss. In particular, when the multi-layer structure composite film with intermediate layer P (VDF-HFP) thickness of 6 μm, the energy storage density and energy storage efficiency reach 11.0 J/cm3 and 86.7%, respectively, realizing double-improvement. This work can provide reliable theoretical analysis and experimental guidance for the preparation of high-performance flexible all-organic dielectrics.

Research on Optimal Design of Thermal Emitter Based on Thermal Photovoltaic Technology

Improving the thermal conversion efficiency of thermal photovoltaic system to optimize the design of thermal emitter in thermophotovoltaic has attracted worldwide attention in recent years due to the world’s major power have devoted great efforts to the exploration of outer space. Based on this background, the focus of this study is to adjust the emission spectrum of the thermal emitter to improve the thermoelectric conversion efficiency of the thermal photovoltaic system. Aiming at the problems of emission spectrum and material characteristics, the model of TMM transfer matrix is established, and the problems of solving thermal radiation emission and calculating emission spectrum in Maxwell equation are solved. Use appendix website: https://refractiveindex.info/, the transmittance of 50 nm thick tungsten at the wavelength of 0.3 ~ 5 μ m is obtained to draw the emission spectrum of tungsten. According to the wavelength analysis of tungsten in the people's Republic of China, it is verified to be within a reasonable range. Aiming at the problems of spectrum and material characteristics of composite structures, a TMM transmission matrix model is established. The coherent light reflection and transmission of multilayer material structure are expressed as the product of matrix. The relationship equation between the properties of multilayer material and its emission spectrum is obtained, and the problem of emission spectrum is solved.

Microstructural and Mechanical Properties of Multi-Layered Materials Composed of Ti-6al-4v, Vanadium, and 17-4ph Stainless Steel Produced by Directed Energy Deposition

Microstructural and Mechanical Properties of Multi-Layered Materials Composed of Ti-6al-4v, Vanadium, and 17-4ph Stainless Steel Produced by Directed Energy Deposition

A hybrid method of predicting the acoustical properties of multi-layered materials

Many numerical and measuring approaches are widely used in predicting and analysing the acoustic performances of laminated materials for noise control applications. However, numerical methods generally require a set of non-acoustic parameters, and the measuring methods are not available for exceedingly thick materials. The main aim of this article is to address a hybrid approach of evaluating the normal incidence sound transmission loss and absorption coefficients of multi-layered materials. This method is performed with some special parameters that contain the sound transmission and reflection coefficients of each sub-layer of a multi-layer specimen and can be measured by a standing wave tube system. The accuracy and feasibility of the present method are validated by the experimental and numerical comparisons between different methods and samples. Moreover, this present approach can be applied as a numerical tool of estimating the acoustical behaviours of multi-layered structures in noise control treatments, such as automotive, building and aerospace industries.

Study of structure and properties of multilayer materials based on titanium alloys

sThe article presents the results of the study of the structure and properties of multilayer materials based on titanium alloys of various classes. The selection of initial compositions founded upon the approach previously tested in the development of multilayer materials based on steels is presented. The basic possibility of forming a laminar structure in titanium multilayer materials has been shown. Based on the analysis of the microstructure, especially the interlayer boundaries, the starting composition that is most suitable for this purpose has been proposed. In reliance upon the conducted tensile tests, it was established that multilayer materials based on titanium alloys have a complex of mechanical properties characteristic of this class of materials. The impact hardness tests performed, as well as the subsequent fractographic studies, allowed concluding about the effect of the condition of the interlayer boundary on the increase in the resistance of the material to dynamic fracture.

Investigating dynamic-mechanical properties of multi-layered materials for biomedical applications

Abstract The development and advancement of polymeric implant materials is a frequent focus in current research. The combination of polymeric materials with diverging properties provides a wide range of new materials with innovative characteristics. One technology for combining materials is to apply a coated layer onto a base material. In this work, a hyperelastic, synthetic base material was combined with a rigid biopolymer coating layer. A multilayered material with combined characteristics of both was built. In the field of processed polymers, the analysis of coating adhesion is not feasible using established methods. Therefore, a dynamic-mechanical method was investigated, which supplements the uniaxial tensile test and provides knowledge regarding mechanical resistance of the multilayered polymer structure. Furthermore, the method gets validated by SEM-imaging and evaluation of coating composition before and after testing under dynamic conditions.

High-Barrier and Antioxidant Poly(lactic acid)/Nanocellulose Multilayered Materials for Packaging.

In the current context, the development of bio-based and high-performance materials is one of the main research priorities. This study aims to combine the outstanding properties of cellulose nanofibrils (CNFs) or nanocrystals (CNCs) with those of bio-based poly(lactic acid) (PLA). Three-phase multilayered materials (TMLs) were built up by complexing a dry CNF- or CNC-based film with two PLA sheets, using a heat-pressing process. Before the preparation of the nanocellulosic films, CNFs and CNCs were modified by the adsorption of a rosin-based nanoemulsion. The rosin mixture as a natural compound is of interest because of its low cost, renewability, hydrophobicity, and its antimicrobial and antioxidant properties. After demonstrating the efficiency of the complexing procedure, we investigated the barrier properties of the multilayered materials against both oxygen and water vapor, with highly encouraging results. In fact, the presence of nanocellulose as an inner layer between the two PLA films significantly enhanced the oxygen barrier, with a decrease in oxygen permeability comprised between 84 and 96% and between 44 and 50% for neat nanocelluloses and nanocelluloses with rosins as the inner layer, respectively. On the other hand, the antioxidant properties of the final multilayered materials including rosins were highlighted, with a highly encouraging radical scavenging activity close to 20%. Because of the simplicity and the efficiency of the proposed method, this study paves the way toward the development of hybrid multimaterials that could be highly attractive for food packaging applications.

Thermal protective qualities of the combined material with reflective thermal insulation from aluminium foil

The article presents the results of experimental and theoretical studies of the thermal insulation qualities of foamed polyethylene with layers of reflective thermal insulation located in its thickness. Currently, the determination of the heat-protection properties of multilayer materials with reflective thermal insulation is carried out experimentally in laboratory conditions. Theoretical studies of the processes of heat transfer in the bulk of such multilayer materials and developed thermophysical model of the heat transfer process through this combined multilayer thermal insulation allowed to develop an engineering calculation method for determining the thermal resistance of multilayer polyethylene foam with reflective thermal insulation from aluminium foil, taking into account thermal conductivity and radiation. The obtained values of the thermal resistance of multilayer polyethylene of various thicknesses by calculation showed the convergence with experimental values. This indicates that reflective thermal insulation with a low emissivity of the surface, located in the thickness of the foamed polyethylene, increases its thermal performance qualities.

Review on Accumulative Roll Bonding (ARB) Techniques for Improving the Mechanical Properties of Multi-Layered Materials

Accumulative Roll Bonding (ARB) is one among the techniques in Severe Plastic Deformation (SPD) which is used to produce ultrafine grains and nanocrystalline structure in the materials used. Tensile test, micro hardness test, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and bending tests are the various tests carried out to understand the grain refinement of ARB materials. ARB is carried out in homogenous and heterogeneous materials to bring out the useful applications of ultrafine grained materials. ARB process mainly carried out in room, warm and hot temperature. The variations in the structure of the material are obtained by changing the load applied on the roller and by increasing the number of passes. This review paper brings out how the mechanical properties of the materials are improved by ARB process

Vulnerability analysis on the interaction between Asymmetric stent and arterial layer.

The utilization of Asymmetric stent for recovering atherosclerotic diseases, particularly non-symmetric obstruction, is a quite challenging breakthrough treatment. In terms of eccentric plaque, the non-uniform stiffness of arterial layer causes the increasingly complex issues of vulnerability. This study investigated the vulnerability of the interaction between the Asymmetric stent and the surrounding arterial layer using structural transient dynamic analysis in ANSYS. Four combinations of stent deployment, i.e. the Sinusoidal stent expanded by the offset balloon, the Sinusoidal stent expanded by the ordinary cylindrical balloon, the Asymmetric stent expanded by the offset balloon, and the Asymmetric stent expanded by the ordinary cylindrical balloon, are generated for this comparative study. Multilayer material properties from recent in vitro experiments are adopted for the surrounding arterial layer, such as a fibrous cap, lipid core, diseased-healthy intima, and diseased-healthy media. In order to address plaque vulnerability, the Cauchy stresses and Hencky strains are used for stress measure because of convenience in comparison with the uniaxial/biaxial tension test data. The location-specific threshold value from the diseased human carotid artery is adopted for rupture criteria. The simulation indicated that as regards the eccentric plaque, the plaque vulnerability is caused by the plaque shape and components rather than caused by the geometrical structure of the stent or balloon expansion method. Nevertheless, the non-symmetric inflation of balloon, which leads against the plaque, contributed to an increase in the vulnerability of fibrous cap of fibroatheroma plaque.

Atomic force microscopy methodology and AFMech Suite software for nanomechanics on heterogeneous soft materials

Atomic force microscopy has proven to be a valuable technique to characterize the mechanical and morphological properties of heterogeneous soft materials such as biological specimens in liquid environment. Here we propose a 3-step method in order to investigate biological specimens where heterogeneity hinder a quantitative characterization: (1) precise AFM calibration, (2) nano-indentation in force volume mode, (3) array of finite element simulations built from AFM indentation events. We combine simulations to determine internal geometries, multi-layer material properties, and interfacial friction. In order to easily perform this analysis from raw AFM data to simulation comparison, we propose a standalone software, AFMech Suite comprising five interacting interfaces for simultaneous calibration, morphology, adhesion, mechanical, and simulation analysis. We test the methodology on soft hydrogels with hard spherical inclusions, as a soft-matter model system. Finally, we apply the method on E. coli bacteria supported on soft/hard hydrogels to prove usefulness in biological field.

Tunable quantum order in bilayer Bi2Te3: Stacking dependent quantum spin Hall states

Recent years have seen the rising importance of interface stacking in determining the electronic properties of multilayer materials stemming from the interlayer coupling; however, the stacking effects on exotic topological quantum orders largely remain to be explored. Here, we show by first-principles studies that bilayer Bi2Te3 host stacking is dependent on quantum spin Hall effects, with a topological phase transition induced by a change in the interlayer stacking pattern. The spin-filtered helical edge states are concomitantly switched on/off along with the changing interlayer stacking pattern. Since few-layer Bi2Te3 has already been experimentally synthesized, the present finding opens an avenue for exploring the fundamental mechanisms and the practical implications of the quantum phenomena associated with band topology in this versatile and intriguing 2D material.

Overall thermomechanical properties of layered materials for energy devices applications

This paper is concerned with the analysis of effective thermomechanical properties of multi-layered materials of interest for solid oxide fuel cells (SOFC) and lithium ions batteries fabrication. The recently developed asymptotic homogenization procedure is applied in order to express the overall thermoelastic constants of the first order equivalent continuum in terms of microfluctuations functions, and these functions are obtained by the solution of the corresponding recursive cell problems. The effects of thermal stresses on periodic multi-layered thermoelastic composite reproducing the characteristics of solid oxide fuel cells (SOFC-like) are studied assuming periodic body forces and heat sources, and the solution derived by means of the asymptotic homogenization approach is compared with the results obtained by finite elements analysis of the associate heterogeneous material.

Determination of properties of sheet damping material with viscoelastic coupling layer during shear deformation

The paper proposes a scheme of testing with a uniform deformation for measuring the properties of multi-layer material with viscoelastic connective layer while performing experiments on the shift. Experimental results showing the features of large shear deformation of a viscoelastic layer and the elastic layer in the samples are provided.

Multilayer material properties of aorta determined from nanoindentation tests

In a wide range of biomechanical modeling of aorta from traumatic injury to stent grafts, the arterial wall has been considered as a single homogeneous layer vessel, ignoring the fact that arteries are composed of distinct anatomical layers with different mechanical characteristics. In this study, using a custom-made nanoindentation technique, changes in the mechanical properties of porcine thoracic aorta wall in the radial direction were characterized using a quasi-linear viscoelastic model. Two layers of equal thickness were mechanically distinguishable in descending aorta based on the radial variations in the instantaneous Young's modulus E and reduced relaxation function G(t). Overall, comparison of E and G∞ of the outer half (70.27±2.47kPa and 0.35±0.01) versus the inner half (60.32±1.65kPa and 0.33±0.01) revealed that the outer half was stiffer and showed less relaxation. The results were used to explain local mechanisms of deformation, force transmission, tear propagation and failure in arteries.

Hydration and internal properties of polyelectrolyte multilayers

In this review we summarize novel aspects of the hydration and internal properties of polyelectrolyte multilayers formed by layer-by-layer assembly. Reflectivity techniques monitor the water content and swelling behavior, while spin relaxation monitors water mobility. Odd–even effects in dependence on the number of layers are discussed in terms of an influence of the terminating layer. Other novel methodological approaches like X-ray microscopy or NMR cryoporometry address the water content in hollow capsules, and the water pore size distribution, respectively. Multilayer material properties are relevant for different applications. As a novel concept, dielectric properties are monitored in a field effect transistor device. Ion mobility and redox processes in multilayers are revealed by the electrochemical properties. Mechanical properties of multilayers, studied by colloidal probe atomic force microscopy depend on the conformation of the polymers involved.