scholarly journals Fabrication and Mechanical Properties of Rolled Aluminium Unidirectional Cellular Structure

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 770 ◽  
Author(s):  
Matej Vesenjak ◽  
Masatoshi Nishi ◽  
Toshiya Nishi ◽  
Yasuo Marumo ◽  
Lovre Krstulović-Opara ◽  
...  
Keyword(s):  
Cellular Structure ◽  
Dynamic Testing ◽  
Rate Sensitivity ◽  
Fabrication Process ◽  
Foil Thickness ◽  
Metallographic Analysis ◽  
Explosive Compaction ◽  
Novel Approach ◽  
Strain Behaviour ◽  
Wavy Interface

The paper focuses on the fabrication of novel aluminium cellular structures and their metallographic and mechanical characterisation. The aluminium UniPore specimens have been manufactured by rolling a thin aluminium foil with acrylic spacers for the first time. The novel approach allows for the cheaper and faster fabrication of the UniPore specimens and improved welding conditions since a lack of a continuous wavy interface was observed in the previous fabrication process. The rolled assembly was subjected to explosive compaction, which resulted in a unidirectional aluminium cellular structure with longitudinal pores as the result of the explosive welding mechanism. The metallographic analysis confirmed a strong bonding between the foil surfaces. The results of the quasi-static and dynamic compressive tests showed stress–strain behaviour, which is typical for cellular metals. No strain-rate sensitivity could be observed in dynamic testing at moderate loading velocities. The fabrication process and the influencing parameters have been further studied by using the computational simulations, revealing that the foil thickness has a dominant influence on the final specimen geometry.

Metallographic analysis of M2 high speed steel granules

2019 ◽  
pp. 78-85
Author(s):  
L. E. Afanasieva
Keyword(s):  
Solid Solution ◽  
Cellular Structure ◽  
High Speed ◽  
Solution Structure ◽  
Supersaturated Solid Solution ◽  
High Speed Steel ◽  
Metallographic Analysis ◽  
M2 High Speed Steel ◽  
Melt Composition

The article is devoted to the metallographic analysis of the M2 high-speed steel granules. The study is based on the investigation of the microstructure of the M2 high-speed steel granules obtained by melt atomization. It is demonstrated that granules of similar size can harden both by chemically separating and chemically non-separating mechanism. These last ones have supersaturated solid solution structure of the liquid melt composition, a dispersed dendritic-cellular structure and an increased microhardness HV = 10267±201 MPa.

scholarly journals On-chip nanophotonic broadband wavelength detector with 2D-Electron gas

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vishal Kaushik ◽  
Swati Rajput ◽  
Sulabh Srivastav ◽  
Lalit Singh ◽  
Prem Babu ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Detection System ◽  
Low Cost ◽  
Electron Gas ◽  
Fabrication Process ◽  
Novel Approach ◽  
Efficient Alternative ◽  
Wavelength Detector ◽  
On Chip ◽  
Wavelength Detection

Abstract Miniaturized, low-cost wavelength detectors are gaining enormous interest as we step into the new age of photonics. Incompatibility with integrated circuits or complex fabrication requirement in most of the conventionally used filters necessitates the development of a simple, on-chip platform for easy-to-use wavelength detection system. Also, intensity fluctuations hinder precise, noise free detection of spectral information. Here we propose a novel approach of utilizing wavelength sensitive photocurrent across semiconductor heterojunctions to experimentally validate broadband wavelength detection on an on-chip platform with simple fabrication process. The proposed device utilizes linear frequency response of internal photoemission via 2-D electron gas in a ZnO based heterojunction along with a reference junction for coherent common mode rejection. We report sensitivity of 0.96 μA/nm for a broad wavelength-range of 280 nm from 660 to 940 nm. Simple fabrication process, efficient intensity noise cancelation along with heat resistance and radiation hardness of ZnO makes the proposed platform simple, low-cost and efficient alternative for several applications such as optical spectrometers, sensing, and Internet of Things (IOTs).

scholarly journals Biochemical characterization of catilages by a novel approach of blunt impact testing

2007 ◽  
pp. S61-S68
Author(s):  
F Varga ◽  
M Držík ◽  
M Handl ◽  
J Chlpík ◽  
P Kos ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Dynamic Testing ◽  
Hysteresis Loops ◽  
Impact Testing ◽  
Cartilage Tissue ◽  
Dissipation Energy ◽  
Blunt Impact ◽  
Novel Approach ◽  
Wide Range ◽  
Definition Of

The present article introduces a novel method of characterizing the macromechanical cartilage properties based on dynamic testing. The proposed approach of instrumented impact testing shows the possibility of more detailed investigation of the acting dynamic forces and corresponding deformations within the wide range of strain rates and loads, including the unloading part of stress-strain curves and hysteresis loops. The presented results of the unconfined compression testing of both the native joint cartilage tissues and potential substitute materials outlined the opportunity to measure the dissipation energy and thus to identify the initial mechanical deterioration symptoms and to introduce a better definition of material damage. Based on the analysis of measured specimen deformation, the intact and pathologically changed cartilage tissue can be distinguished and the differences revealed.

160 MILLI-OHM ELECTRICAL RESISTANCE THRU-WAFER INTERCONNECTS WITH 10:1 ASPECT RATIO

2014 ◽  
Vol 2014 (1) ◽  
pp. 000505-000510 ◽  
Author(s):  
A. Efimovskaya ◽  
A.M. Shkel
Keyword(s):  
Aspect Ratio ◽  
Microelectromechanical Systems ◽  
Equivalent Circuit Model ◽  
Signal Amplitude ◽  
Parasitic Capacitance ◽  
Fabrication Process ◽  
Silicon On Insulator ◽  
Measurement Unit ◽  
Novel Approach ◽  
Electroplating Process

We present a novel approach for high-aspect ratio low resistance Thru-Wafer Interconnects for Double-Sided (TWIDS) fabrication of MicroElectroMechanical Systems (MEMS). The interconnects are formed by etching blind via holes in the handle substrate of an SOI (Silicon on Insulator) wafer, followed by filling the holes with copper, using sonic-assisted seedless copper electroplating process. This technique does not require additional conductive layer deposition, but utilizes a highly doped silicon device layer as a seed. The donut-shape gaps are etched around the copper filled vias to provide interconnects insulation. We introduced the fabrication process and characterized the performance of interconnects. Experimental analysis of an array of 22 interconnects demonstrated that the resistance values as low as 160 milli-Ohm can be achieved. Parasitic capacitance of interconnects is analytically calculated and the distortion of the MEMS resonator transduction spectrum is predicted using an equivalent circuit model. Signal amplitude and phase distortion due to the parasitic capacitance are estimated to be 1.15 dB and 5.96 deg, respectively, for the optimum 60 um diameter via with 35 um insulating gap. The method presented is compatible with an in-house folded MEMS fabrication process and may enable 3D folded TIMU (Timing Inertial Measurement Unit) structures with thru-wafer interconnects.

scholarly journals Development of Unidirectional Cellular Structure with Multiple Pipe Layers and Characterisation of Its Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3880
Author(s):  
Matej Vesenjak ◽  
Yutaka Nakashima ◽  
Kazuyuki Hokamoto ◽  
Zoran Ren ◽  
Yasuo Marumo
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Cellular Structure ◽  
Cellular Materials ◽  
Constant Cross Section ◽  
Explosive Compaction ◽  
Typical Behaviour ◽  
Compressive Testing ◽  
Copper Structure ◽  
Transversal Cross Section

This study is concerned with the development of a new unidirectional cellular (UniPore) copper structure with multiple concentric pipe layers. The investigated UniPore structures were grouped into three main types, each having a different number of pipes (3, 4, and 5 pipes per transversal cross-section) and different pore arrangements. The specimens were fabricated by explosive compaction to achieve tightly compacted structures with a quasi-constant cross-section along the length of the specimens. The bonding between copper pipes was observed by a metallographic investigation, which showed that the pipes and bars were compressed tightly without voids. However, they were not welded together. The mechanical properties were determined by quasi-static compressive testing, where the typical behaviour for cellular materials was noted. The study showed that porosity significantly influences the mechanical properties, even more so than the arrangement of the pipes.

scholarly journals Crystal-Plasticity-Finite-Element Modeling of the Quasi-Static and Dynamic Response of a Directionally Solidified Nickel-Base Superalloy

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2990
Author(s):  
Rafael Sancho ◽  
Javier Segurado ◽  
Borja Erice ◽  
María-Jesús Pérez-Martín ◽  
Francisco Gálvez
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Crystal Plasticity ◽  
Dynamic Testing ◽  
Rate Sensitivity ◽  
Growth Direction ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Nickel Base ◽  
Base Superalloy

The flow stress behaviour of a directionally solidified nickel-base superalloy, MAR-M247, is presented through the combination of experiments and crystal-plasticity simulations. The experimental campaign encompassed quasi-static and dynamic testing in the parallel and perpendicular orientation with respect to the columnar grains. The material showed low strain-rate sensitivity in all cases. Virtual samples were generated with DREAM3d and each grain orientation was established according to the DS nature of the alloy. The elasto-visco-plastic response of each crystal is given by phenomenological-base equations, considering the dislocation–dislocation interactions among different slip systems. The hardening-function constants and the strain-rate sensitivity parameter were fitted with the information from tests parallel to the grain-growth direction and the model was able to predict with accuracy the experimental response in the perpendicular direction, confirming the suitability of the model to be used as a tool for virtual testing. Simulations also revealed that in oligocrystalline structures of this type, the yield-strength value is controlled by the grains with higher Schmid factor, while this influence decreases when plastic strain increases. Moreover, the analysis of the micro-fields confirmed that grains perpendicular to the loading axis are prone to nucleate cavities since the stresses in these regions can be twice the external applied stress.

Static and Dynamic Collapse Characteristics of Scale Model Corrugated Tubular Sections

1975 ◽  
Vol 97 (4) ◽  
pp. 357-362 ◽  
Author(s):  
P. H. Thornton
Keyword(s):  
Scaling Laws ◽  
Dynamic Testing ◽  
Plastic Hinge ◽  
Rate Sensitivity ◽  
Scale Model ◽  
Complex Deformation ◽  
Collapse Characteristics ◽  
Rate Effects ◽  
Deformation Processes ◽  
Tubular Sections

The collapse load of a series of scale model, corrugated tubular sections was determined, both by quasi-static and by dynamic testing. Provided that the material from which the models are made is identical to that of the full size component, then the scaling laws for structures undergoing complex deformation processes will be obeyed. The dynamic collapse response, which occurred by the operation of a plastic hinge mechanism, is governed by the strain rate sensitivity of the material; structural rate effects do not affect the collapse process.

scholarly journals A Novel Approach for Dynamic Testing of Total Hip Dislocation under Physiological Conditions

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0145798 ◽  
Author(s):  
Sven Herrmann ◽  
Daniel Kluess ◽  
Michael Kaehler ◽  
Robert Grawe ◽  
Roman Rachholz ◽  
...  
Keyword(s):  
Dynamic Testing ◽  
Hip Dislocation ◽  
Physiological Conditions ◽  
Total Hip ◽  
Novel Approach
Sign in / Sign up

Export Citation Format

Share Document