Multilayer Microelectromechanical Structures for Material Property Characterization

1998 ◽  
Vol 518 ◽  
Author(s):  
R. I. Pratt ◽  
G. C. Johnson
Keyword(s):  
Mass Density ◽  
Base Material ◽  
Single Layer ◽  
Analytical Techniques ◽  
Multilayer Structures ◽  
New Materials ◽  
Multilayered Structures ◽  
Micro Electro Mechanical Systems ◽  
Resonant Structures ◽  
Rigid Mass

AbstractA new class of micro-electro-mechanical systems (MEMS) for material characterization is presented. These multilayered structures are lateral resonators which allow the determination of material properties of the different materials making up the system. Of particular significance is the ability to characterize many new materials previously untestable by resonant techniques. The basic lateral resonant structures are made of a single material, usually doped polycrystalline silicon, with beams anchored to the substrate at one end and supporting a rigid mass at the other. The rigid mass has a comb-shaped region on each side for electrostatically actuating and sensing the motion. The use of this electrostatic comb drive requires that the structure be made of a material that is electrically conductive. Thus, the class of materials which is amenable to characterization by resonance techniques has been somewhat limited. Multilayer structures, tested in conjunction with these basic monolithic structures, permit properties of both the base material and the subsequent layers to be determined. Stiffness and mass density of many new materials can be obtained by comparing the behavior of multilayer structures with their single-layer counterparts. Experimental designs and the associated analytical techniques for obtaining various properties are presented.

scholarly journals Vibration analysis of a sandwich cylindrical shell in hygrothermal environment

2021 ◽  
Vol 10 (1) ◽  
pp. 414-430
Author(s):  
Chunwei Zhang ◽  
Qiao Jin ◽  
Yansheng Song ◽  
Jingli Wang ◽  
Li Sun ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Single Layer ◽  
Functionally Graded ◽  
Sandwich Shell ◽  
Continuous Change ◽  
Multilayered Structures ◽  
Cylindrical Sandwich Shell ◽  
Vibrational Behavior

Abstract The sandwich structures are three- or multilayered structures such that their mechanical properties are better than each single layer. In the current research, a three-layered cylindrical shell including a functionally graded porous core and two reinforced nanocomposite face sheets resting on the Pasternak foundation is used as model to provide a comprehensive understanding of vibrational behavior of such structures. The core is made of limestone, while the epoxy is utilized as the top and bottom layers’ matrix phase and also it is reinforced by the graphene nanoplatelets (GNPs). The pattern of the GNPs dispersion and the pores distribution play a crucial role at the continuous change of the layers’ properties. The sinusoidal shear deformation shells theory and the Hamilton’s principle are employed to derive the equations of motion for the mentioned cylindrical sandwich shell. Ultimately, the impacts of the model’s geometry, foundation moduli, mode number, and deviatory radius on the vibrational behavior are investigated and discussed. It is revealed that the natural frequency and rotation angle of the sandwich shell are directly related. Moreover, mid-radius to thickness ratio enhancement results in the natural frequency reduction. The results of this study can be helpful for the future investigations in such a broad context. Furthermore, for the pipe factories current study can be effective at their designing procedure.

scholarly journals Analysis of Different Complex Multilayer PACVD Coatings on Nanostructured WC-Co Cemented Carbide

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 823
Author(s):  
Danko Ćorić ◽  
Mateja Šnajdar Musa ◽  
Matija Sakoman ◽  
Željko Alar
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Base Material ◽  
Single Layer ◽  
Production Costs ◽  
Structural Defects ◽  
Cemented Carbides ◽  
Material System ◽  
Tin Coating ◽  
Ticn Coating

The development of cemented carbides nowadays is aimed at the application and sintering of ultrafine and nano-sized powders for the production of a variety of components where excellent mechanical properties and high wear resistance are required for use in high temperature and corrosive environment conditions. The most efficient way of increasing the tribological properties along with achieving high corrosion resistance is coating. Using surface processes (modification and/or coating), it is possible to form a surface layer/base material system with properties that can meet modern expectations with acceptable production costs. Three coating systems were developed on WC cemented carbides substrate with the addition of 10 wt.% Co using the plasma-assisted chemical vapor deposition (PACVD) method: single-layer TiN coating, harder multilayer gradient TiCN coating composed of TiN and TiCN layers, and the hardest multilayer TiBN coating composed of TiN and TiB2. Physical and mechanical properties of coated and uncoated samples were investigated by means of quantitative depth profile (QDP) analysis, nanoindentation, surface layer characterization (XRD analysis), and coating adhesion evaluation using the scratch test. The results confirm the possibility of obtaining nanostructured cemented carbides of homogeneous structure without structural defects such as eta phase or unbound carbon providing increase in hardness and fracture toughness. The lowest adhesion was detected for the single-layer TiN coating, while coatings with a complex architecture (TiCN, TiBN) showed improved adhesion.

scholarly journals Characteristics of Oceanic Warm Cloud Layers within Multilevel Cloud Systems Derived by Satellite Measurements

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 465 ◽  
Author(s):  
Yuhao Ding ◽  
Qi Liu ◽  
Ping Lao
Keyword(s):  
Double Layer ◽  
Lower Layer ◽  
Single Layer ◽  
Distribution Patterns ◽  
Radar Data ◽  
Multilayered Structures ◽  
Layer System ◽  
Cloud Systems ◽  
Warm Cloud ◽  
Double Layer System

Low-level warm clouds are a major component in multilayered cloud systems and they are generally hidden from the top-down view of satellites with passive measurements. This study conducts an investigation on oceanic warm clouds embedded in multilayered structures by using spaceborne radar data with fine vertical resolution. The occurrences of warm cloud overlapping and the geometric features of several kinds of warm cloud layers are examined. It is found that there are three main types of cloud systems that involve warm cloud layers, including warm single layer clouds, cold-warm double layer clouds, and warm-warm double layer clouds. The two types of double layer clouds account for 23% and in the double layer occurrences warm-warm double layer subsets contribute about 13%. The global distribution patterns of these three types differ from each other. Single-layer warm clouds and the lower warm clouds in the cold-warm double layer system they have nearly identical geometric parameters, while the upper and lower layer warm clouds in the warm-warm double layer system are distinct from the previous two forms of warm cloud layers. In contrast to the independence of the two cloud layers in cold-warm double layer system, the two kinds of warm cloud layers in the warm-warm double layer system may be coupled. The distance between the two layers in the warm-warm double layer system is weakly dependent on cloud thickness. Given the upper and lower cloud layer with moderate thickness of around 1 km, the cloudless gap reaches its maximum when exceeding 600 m. The cloudless gap decreases in thickness as the two cloud layers become even thinner or thicker.

Comparison of Electromigration Induced Resistance Changes in Multilayer Al-Si/Ti and Al-Si/Ta Interconnects

1986 ◽  
Vol 71 ◽  
Author(s):  
M. Finetti ◽  
I. Suni ◽  
G. Desanti ◽  
L. Bacci ◽  
C. Caprile
Keyword(s):  
Induced Resistance ◽  
Single Layer ◽  
Multilayer Structures ◽  
Resistance Analysis ◽  
Temperature Ramp

AbstractWe have applied a temperature-ramp resistance analysis to investigate electromigration effects in unpassivated Al-Si/Ta multilayer structures. The results are compared to the behaviour previously observed in Al-Si/Ti interconnects. For comparison, single layer Al-Si metallizations were also studied.

Particle Swarm Optimization Algorithm in Electromagnetics- Case Studies

2012 ◽  
pp. 72-99
Author(s):  
Arezoo Modiri ◽  
Kamran Kiasaleh
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Analytical Techniques ◽  
Pso Algorithm ◽  
Multilayer Structures ◽  
Efficient Design ◽  
Swarm Optimization ◽  
Electromagnetic Problems ◽  
Microwave Techniques ◽  
High Level

This chapter is intended to describe the vast intrinsic potential of the swarm-intelligence-based algorithms in solving complicated electromagnetic problems. This task is accomplished through addressing the design and analysis challenges of some key real-world problems, ranging from the design of wearable radiators to tumor detection tools. Some of these problems have already been tackled by solution techniques other than particle swarm optimization (PSO) algorithm, the results of which can be found in the literature. However, due to the relatively high level of complexity and randomness inherent to these problems, one has to resort to oversimplification in order to arrive at reasonable solutions utilizing analytical techniques. In this chapter, the authors discuss some recent studies that utilize PSO algorithm particularly in two emerging areas; namely, efficient design of reconfigurable radiators and permittivity estimation of multilayer structures. These problems, although unique, represent a broader range of problems in practice which employ microwave techniques for antenna design and microwave imaging.

scholarly journals Predicting the bulk modulus of single-layer covalent organic frameworks with square-lattice topology from molecular building-block properties

Nanoscale ◽  
2021 ◽  
Author(s):  
Antonios Raptakis ◽  
Arezoo Dianat ◽  
Alexander Croy ◽  
Gianaurelio Cuniberti
Keyword(s):  
Bulk Modulus ◽  
Elastic Properties ◽  
Building Block ◽  
Rational Design ◽  
Computational Study ◽  
Single Layer ◽  
Building Blocks ◽  
Square Lattice ◽  
New Materials ◽  
Molecular Building Block

This computational study establishes a correlation between the elastic properties of COFs and their building-blocks towards the rational design of new materials with tailored properties.

scholarly journals Preparation of Boron Nitride Nanoplatelets via Amino Acid Assisted Ball Milling: Towards Thermal Conductivity Application

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1652
Author(s):  
Nan Yang ◽  
Haifeng Ji ◽  
Xiaoxia Jiang ◽  
Xiongwei Qu ◽  
Xiaojie Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Amino Acid ◽  
Boron Nitride ◽  
Ball Milling ◽  
Hexagonal Boron Nitride ◽  
Base Material ◽  
Single Layer ◽  
Self Healing ◽  
Dispersion State ◽  
Pva Hydrogel

Hexagonal boron nitride nanoplatelets (BNNPs) have attracted widespread attention due to their unique physical properties and their peeling from the base material. Mechanical exfoliation is a simple, scalable approach to produce single-layer or few-layer BNNPs. In this work, two amino acid grafted boron nitride nanoplatelets, Lys@BNNP and Glu@BNNP, were successfully prepared via ball milling of h-BN with L-Lysine and L-Glutamic acid, respectively. It was found that the dispersion state of Lys@BNNP and Glu@BNNP in water had been effectively stabilized due to the introduction of amino acid moieties which contained a hydrophilic carboxyl group. PVA hydrogel composites with Lys@BNNP and Glu@BNNP as functional fillers were constructed and extensively studied. With 11.3 wt% Lys@BNNP incorporated, the thermal conductivity of Lys@BNNP/PVA hydrogel composite was up to 0.91 W m−1K−1, increased by 78%, comparing to the neat PVA hydrogel. Meanwhile, the mechanical and self-healing properties of the composites were simultaneously largely enhanced.

Dynamic Stress Analysis of Multilayered Structure With Radial Gaps of Cylindrical Pressure Vessel Under Plane Strain Conditions

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Huadong Liu ◽  
Weiqiang Wang
Keyword(s):  
Plastic Deformation ◽  
Dynamic Response ◽  
Plane Strain ◽  
Pressure Vessel ◽  
Single Layer ◽  
Multilayered Structure ◽  
Multilayered Structures ◽  
Loading Process ◽  
Cylindrical Pressure Vessel ◽  
Gap Height

Radial gaps were found in multilayered cylindrical vessels which experience inner explosion accidents in chemical plants in the past few years worldwide. It is necessary to investigate the dynamic response of multilayered structures with radial gaps to ensure the vessel safety. This paper presented a numerical modeling of the dynamic response of a multilayered structure with radial gaps of cylindrical pressure vessel under plane strain conditions by using the ANSYS/ls-dyna package. The effects of the dynamic loading profile and the radial gap height are considered in the investigation. The stress spatial distribution, the stress and the plastic deformation variation curves with time are emphatically analyzed. The results show that the stress variation of the entire loading process can be divided into four stages: the oscillation stage, the yield stage, the fast increase stage, and the redistribution stage. The layer stress distributes discontinuously at the gaps between layers and distributes unevenly in any single layer. The inner layer stress is not always larger than the outer layers' during the whole loading process. The effect of loading profile on the dynamic response is not as obvious as the gap height. As the gap height increases, the stress oscillation stage is suppressed and becomes shorter. While the loading recovers to the operation pressure, the stress and the plastic deformation of inner layers increases and vice versa for the outer layers.

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