Mechanical Response and Incomplete Filling in Compression Molding With Microscale Double-Punch Sets

2019 ◽  
Author(s):  
Bin Zhang ◽  
M. Dodaran ◽  
S. Shao ◽  
W. J. Meng
Keyword(s):  
Mechanical Response ◽  
Ion Beam ◽  
Compression Molding ◽  
Molding Pressure ◽  
Small Scale ◽  
Width Ratio ◽  
Significant Dependence ◽  
Incomplete Filling ◽  
Surface Patterns ◽  
Scale Surface

Abstract Forming nano-/micro-scale surface patterns on metal surfaces by direct compression molding is an important means for achieving small scale surface features with potential usage in wide ranging technological applications. Geometric fidelity of molded features and the corresponding molding response are of critical importance in determining the usefulness of the molding replication technique. In this paper, two series of microscale punches made of tool steels were fabricated using Ga+ focused ion beam (FIB). In one series, the punch consists of a single protruding rectangular strip of different width, w (dubbed the “single punch”). In the other series, the punch consists of two rectangular strips of identical dimensions separated by a spacing in between, s (dubbed the “double punch”). These so-fabricated punches were used to mold elemental single crystal Al. The mechanical response during compression molding was measured and analyzed. For the double-punch experiments, measured characteristic molding pressure exhibited a significant dependence on the spacing to punch width ratio, λ = s/w, as well as a significant dependence on s when λ was fixed. The molded features were examined and the phenomenon of incomplete filling was observed to occur at λ < 0.5.

scholarly journals Nonlinear magneto-thermo-elastic vibration of mass sensor armchair carbon nanotube resting on an elastic substrate

2020 ◽  
Vol 7 (1) ◽  
pp. 153-165
Author(s):  
Rajendran Selvamani ◽  
M. Mahaveer Sree Jayan ◽  
Rossana Dimitri ◽  
Francesco Tornabene ◽  
Farzad Ebrahimi
Keyword(s):  
Carbon Nanotube ◽  
Mechanical Response ◽  
Scale Effects ◽  
Nonlocal Elasticity Theory ◽  
Wave Dispersion ◽  
Elastic Vibration ◽  
Ultrasonic Waves ◽  
Small Scale ◽  
Dimensionless Frequency ◽  
Mass Sensors

AbstractThe present paper aims at studying the nonlinear ultrasonic waves in a magneto-thermo-elastic armchair single-walled (SW) carbon nanotube (CNT) with mass sensors resting on a polymer substrate. The analytical formulation accounts for small scale effects based on the Eringen’s nonlocal elasticity theory. The mathematical model and its differential equations are solved theoretically in terms of dimensionless frequencies while assuming a nonlinear Winkler-Pasternak-type foundation. The solution is obtained by means of ultrasonic wave dispersion relations. A parametric work is carried out to check for the effect of the nonlocal scaling parameter, together with the magneto-mechanical loadings, the foundation parameters, the attached mass, boundary conditions and geometries, on the dimensionless frequency of nanotubes. The sensitivity of the mechanical response of nanotubes investigated herein, could be of great interest for design purposes in nano-engineering systems and devices.

Application of small-scale testing for investigation of ion-beam-irradiated materials

2012 ◽  
Vol 27 (21) ◽  
pp. 2724-2736 ◽  
Author(s):  
Daniel Kiener ◽  
Andrew M. Minor ◽  
Osman Anderoglu ◽  
Yongqiang Wang ◽  
Stuart A. Maloy ◽  
...  
Keyword(s):  
Ion Beam ◽  
Small Scale ◽  
Image Position

Abstract

scholarly journals Investigating the turbulent dynamics of small-scale surface fires

2021 ◽  
Author(s):  
Ajinkya Desai ◽  
Scott Goodrick ◽  
Tirtha Banerjee
Keyword(s):  
Small Scale ◽  
Surface Fires ◽  
Scale Surface

scholarly journals Measurement-free implementations of small-scale surface codes for quantum-dot qubits

2018 ◽  
Vol 97 (1) ◽  
Author(s):  
H. Ekmel Ercan ◽  
Joydip Ghosh ◽  
Daniel Crow ◽  
Vickram N. Premakumar ◽  
Robert Joynt ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Small Scale ◽  
Scale Surface

Double-Sided Microchannel Cooling of a Power Electronics Module Using Power Overlay

2009 ◽  
Author(s):  
Adam G. Pautsch ◽  
Arun Gowda ◽  
Ljubisa Stevanovic ◽  
Rich Beaupre
Keyword(s):  
Power Electronics ◽  
High Performance ◽  
Mechanical Response ◽  
Thermal Contact ◽  
Small Scale ◽  
Micro Channel ◽  
Performance Technology ◽  
Actual Performance ◽  
Low Performance ◽  
Microchannel Cooling

In the continuing effort to alleviate the increasing thermal loads for power electronics devices, numerous aggressive solutions have been developed, such as small-scale micro-channel heat exchangers. Although these methods can improve overall surface heat transfer to the order of 500 W cm−2, they are limited to single-sided cooling due to the typical wire-bonded electrical connections of the devices. Power overlay (POL) technology provides a stable planar structure for electrical connection, as well as attachment of an additional top-side heat exchanger. This study presents an analysis of double-sided microchannel cooling of a power electronics module. Two optimized, integral micro-channel heat sinks were attached above and below silicon power devices, with more traditional attachment on one side and a POL interface on the other. A compliant TIM was selected for low thermal resistance and good mechanical response, which allowed top-side connection to the POL surface. A theoretical model is presented that predicts the benefit of double-sided cooling based on the known performance of a single-sided heat sink and given addition thermal contact resistance for the top side. For microchannels with water, an enhancement of 26% was predicted. An experiment was also carried out to measure the actual performance benefit seen with double-sided cooling. An enhancement of over 30% was measured for a particular design. As the theory predicts, the benefit of double-sided cooling is limited for high performance designs. However, double-sided cooling could lead to high levels of thermal performance using low-performance technology.

scholarly journals Ion Irradiation-Induced Microstructural Evolution of Ni–Mo–Cr Low Alloy Steels

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2268
Author(s):  
Hongying Sun ◽  
Penghui Lei ◽  
Guang Ran ◽  
Hui Wang ◽  
Jiyun Zheng ◽  
...  
Keyword(s):  
Irradiation Dose ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Strength ◽  
Positron Annihilation Spectroscopy ◽  
Small Scale ◽  
Low Alloy Steels ◽  
Dislocation Loops ◽  
S Parameter

As leading candidates of sheet steels for advanced nuclear reactors, three types of Ni–Mo–Cr high-strength low alloy (HSLA) steels named as CNST1, CNST2 and CNSS3 were irradiated by 400 keV Fe+ with peak fluence to 1.4 × 1014, 3.5 × 1014 and 7.0 × 1014 ions/cm2, respectively. The distribution and morphology of the defects induced by the sample preparation method and Fe+ irradiation dose were investigated by transmission electron microscopy (TEM) and positron-annihilation spectroscopy (PAS). TEM samples were prepared with two methods, i.e., a focused ion beam (FIB) technique and the electroplating and twin-jet electropolishing (ETE) method. Point defects and dislocation loops were observed in CNST1, CNST2 and CNSS3 samples prepared via FIB. On the other hand, samples prepared via the ETE method revealed that a smaller number of defects was observed in CNST1, CNST2 and almost no defects were observed in CNST3. It is indicated that artifact defects could be introduced by FIB preparation. The PAS S-W plots showed that the existence of two types of defects after ion implantation included small-scale defects such as vacancies, vacancy clusters, dislocation loops and large-sized defects. The S parameter of irradiated steels showed a clear saturation in PAS response with increasing Fe+ dose. At the same irradiation dose, higher values of the S-parameter were achieved in CNST1 and CNST2 samples when compared to that in CNSS3 samples. The mechanism and evolution behavior of irradiation-induced defects were analyzed and discussed.

scholarly journals COMPRESSION OF ECAPED TITANIUM MICRO-PILLARS FOR TWO PRINCIPAL ORIENTATIONS

2020 ◽  
Vol 27 ◽  
pp. 1-5
Author(s):  
David Vokoun ◽  
Jan Maňák ◽  
Karel Tesař ◽  
Stanislav Habr
Keyword(s):  
Room Temperature ◽  
Focused Ion Beam ◽  
Mechanical Response ◽  
Thermomechanical Processing ◽  
Ion Beam ◽  
Orientation Dependence ◽  
Material Strength ◽  
Angular Pressing ◽  
Macro Scale ◽  
Micro Pillars

The thermomechanical processing by equal-channel angular pressing (ECAP) is used for certain metals and alloys in order to make their structure fine and to increase material strength. In the previous study done at our institute, grade 2 titanium was successfully processed using four consecutive route A passes via a 90 ° ECAP die with high backpressure at room temperature. Orientation dependence of compressive and tensile loading of ECAPed titanium samples was demonstrated at macro-scale. However, scarce attention has been paid so far to the mechanical behavior of ECAPed titanium samples at micro-scale. In the present study, compression experiments on titanium micropillars, fabricated using focused ion beam, are carried out for two main directions in respect to preceding ECAP pressing (insert and extrusion directions). The purpose of this study is to discuss the orientation dependence of mechanical response during compression of the as-ECAPed titanium micro-pillars.

Hemp Fiber Reinforced Unsaturated Polyester Composites

2006 ◽  
Vol 11-12 ◽  
pp. 521-524 ◽  
Author(s):  
Yuan Jian Tong ◽  
Liang Hua Xu
Keyword(s):  
Heat Treatment ◽  
Natural Fiber ◽  
Unsaturated Polyester ◽  
Compression Molding ◽  
Molding Pressure ◽  
Fiber Reinforced ◽  
Hemp Fiber ◽  
Fiber Fraction ◽  
Glass Fiber Reinforced ◽  
Loss Of Weight

Non-woven hemp fiber mat has been used to reinforce unsaturated polyester to make natural fiber composites. Thermal properties of the hemp fiber mat were investigated to discover the range of heat treatment temperatures suitable for the hemp fiber mat. Loss of weight during heat treatment and absorption of moisture from the environment during storage of the hemp fiber mat were also studied. Both hand lay-up technique and compression molding were used to make hemp mat composites. Due to the low fiber fraction, no significant reinforcing effect was found in the composite made by the hand lay-up technique. The effects of heat treatment of fibers, water content in the fibers, fiber fraction, and manufacture methods on tensile properties of the resulted composites were investigated. Hemp mat composites with tensile strength and modulus comparable to those of [±45°]4 glass fiber reinforced polyester were achieved by compression molding at a molding pressure of 2MPa.

Lubricant migration on stainless steel induced by bio-inspired multi-scale surface patterns

2018 ◽  
Vol 150 ◽  
pp. 55-63 ◽  
Author(s):  
Philipp G. Grützmacher ◽  
Andreas Rosenkranz ◽  
Adam Szurdak ◽  
Carsten Gachot ◽  
Gerhard Hirt ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Multi Scale ◽  
Surface Patterns ◽  
Lubricant Migration ◽  
Scale Surface

A finite element model to study the effect of porosity location on the elastic modulus of a cantilever beam

2019 ◽  
Vol 43 (4) ◽  
pp. 443-453
Author(s):  
Stephen M. Handrigan ◽  
Sam Nakhla
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Focused Ion Beam ◽  
Mechanical Response ◽  
Ion Beam ◽  
Three Dimensional ◽  
Beam Theory ◽  
Element Model ◽  
Fe Model ◽  
Three Dimensional Finite Element

An investigation to determine the effect of porosity concentration and location on elastic modulus is performed. Due to advancements in testing methods, the manufacturing and testing of microbeams to obtain mechanical response is possible through the use of focused ion beam technology. Meanwhile, rigorous analysis is required to enable accurate extraction of the elastic modulus from test data. First, a one-dimensional investigation with beam theory, Euler–Bernoulli and Timoshenko, was performed to estimate the modulus based on load-deflection curve. Second, a three-dimensional finite element (FE) model in Abaqus was developed to identify the effect of porosity concentration. Furthermore, the current work provided an accurate procedure to enable accurate extraction of the elastic modulus from load-deflection data. The use of macromodels such as beam theory and three-dimensional FE model enabled enhanced understanding of the effect of porosity on modulus.

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