Preferential Orientation Dependent Mechanical and Electrical Properties in Naβ-Alumina Ceramics

2006 ◽  
Vol 301 ◽  
pp. 147-150 ◽  
Author(s):  
Akira Kishimoto ◽  
Kousei Shimokawa
Keyword(s):  
Ionic Conductivity ◽  
Mechanical Strength ◽  
Hot Pressing ◽  
Bending Test ◽  
Two Dimensional ◽  
Mechanical Reliability ◽  
Alumina Ceramics ◽  
Three Point Bending ◽  
Mechanical And Electrical Properties ◽  
Test Pieces

Nab-alumina is a two- dimensional ionic conductor in which conducting planes of Na+ ion are separated by insulating spinel block layers. For practical use, Nab- alumina needs not only high ionic conductivity but also mechanical reliability. Therefore, we prepared preferentially oriented Nab-alumina ceramics by hot pressing and evaluated the ionic conductivity and mechanical strength. The ionic conductivity perpendicular to the c-axis-oriented plane was five times higher than that parallel to c-axis. From the preferentially oriented Nab-alumina ceramics three types of test pieces were cut for a three-point bending test. In one type of test piece, the longest side was parallel to the hot-pressing direction, while the longest sides were perpendicular to that direction in the other types of test pieces. The latter test pieces showed mechanical strength 1.5 times that of the former.

scholarly journals The relationship between microstructure and mechanical properties of directly bonded copper-alumina ceramics joints

2014 ◽  
Vol 62 (1) ◽  
pp. 23-32 ◽  
Author(s):  
K. Pietrzak ◽  
W. Olesinska ◽  
D. Kalinski ◽  
A. Strojny-Nedza
Keyword(s):  
Mechanical Strength ◽  
Transition Layer ◽  
Diffraction Method ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
Microscopy Method ◽  
Materials Used ◽  
The Individual

Abstract The effect of phase transformations induced in the surface layer of alumina ceramics during its direct joining with copper activated with oxygen or titanium on the mechanical strength of the ceramic/copper joints was examined. The materials used in the experiments were an alumina single crystal, alumina ceramics (97.5 wt% Al2O3), the cermet mixtures: Cu-Cu2O with 10-50 wt% of Cu2O, copper with 5 wt% of Ti, and copper with 5 wt% of Ti and 10 wt% of Ag. The microstructure of the transition layer was examined by the X-ray diffraction method (XRD), scanning electron microscopy method (SEM) and energy dispersive x-ray spectroscopy (EDX). The mechanical strength of the joints was measured using the three-point bending method. The amount of oxygen optimal for the joining process was determined. It has been demonstrated that the cohesion of the joints depends not only on the formation of the individual phases but also, or even primarily, on the microstructure of the transition layer formed between them.

scholarly journals A Mathematical Solution for Calculating the Springback of Laminated Beech Stacks Molded within the Elastic Range

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 725 ◽  
Author(s):  
Moritz Sanne ◽  
Gudrun Ahn-Ercan ◽  
Alexander Pfriem
Keyword(s):  
Negligible Effect ◽  
Elastic Region ◽  
Bending Test ◽  
Internal Stresses ◽  
Mathematical Solution ◽  
Three Point Bending ◽  
Elastic Range ◽  
Test Pieces ◽  
Polyurethane Resin ◽  
Molded Wood

The springback effect in molded wood laminations within the elastic range has, to date, not yet been mathematically described. Once cured, residual internal stresses within the laminations cause the final form to deviate from that of the die. Test pieces of beech laminations of 1 mm, 2 mm and 4 mm thicknesses and stack sizes of between 2 and 16 laminations were used. The elasticity value of each stack was obtained using non-glued laminations in a three-point bending test within the elastic region. The laminations were glued with polyurethane resin and mounted in a radius form die. The stress induced by the die onto the stack is within the elastic region of the material without any prior chemical or physical plasticisation of the wood. After curing was complete and the laminations removed from the die, the actual radius was calculated using a circular equation within the CAD program, using three measurement points taken from the stack. The radius of the die within the limits of this study has a negligible effect when predicting the springback of the stack. The exponential correlation between springback and the number of laminations, was used to calculate the springback effect on molded laminated stacks.

Fabrication of High Strength α-SiAlON/BN Composition Ceramics by Hot Pressing

2012 ◽  
Vol 512-515 ◽  
pp. 816-819 ◽  
Author(s):  
Ying Chun Shan ◽  
Guang Wang ◽  
Hui Ye ◽  
Xiao Guang Han ◽  
Jiu Jun Xu ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
High Strength ◽  
Bending Test ◽  
Composite Ceramics ◽  
Major Phase ◽  
Three Point Bending ◽  
Powder Body

Dense Y3+-dopted α-SiAlON/BN composition ceramics was fabricated by hot pressing at 1900 °C for 60 min, and flextural strength at room and 1000 °C was investigated through three-point bending test. The results show that h-BN contribute to the densification of powder body, but h-BN have little affect on the key temperature region of sintering densification of α-SiAlON ceramics. When content of BN is lower, which didn’t affect on the phase transformation of α-SiAlON, but when content of BN is higher, besides of major phase α-SiAlON, a little of β-SiAlON was also formed. For the α-SiAlON/BN composite ceramics content of 20 wt.% h-BN, the higer flexural strength( room-temperature and 1000 °C) were abtained, the formation of β-SiAlON should be an important resonon for the higher strentgh, more important is , whose flexural strength at 1000 °C is higher 50 MPa than at room temperature, the differnce of thermal properties between SiAlON and BN should contribute to the improve of high-temperature flextural strength.

Manipulation of Thin Metallic Wires by Joule Heat Joining

2009 ◽  
Author(s):  
Hironori Tohmyoh ◽  
Hironao Takeda ◽  
M. A. Salam Akanda ◽  
Masumi Saka
Keyword(s):  
Potential Drop ◽  
Bending Test ◽  
Core Wire ◽  
Thin Wire ◽  
Electromagnetic Actuators ◽  
Three Point Bending ◽  
Simply Supported ◽  
Mechanical And Electrical Properties ◽  
Thin Wires ◽  
Metallic Wires

Various kinds of metallic thin wires are expected to be key elements in future NEMS or MEMS due to their excellent physical properties and geometrical merits. However, it is not so easy task to manipulate thin wires for many kinds of application nowadays. We report manipulation techniques based on weld-joining on a substrate by Joule heating. The Pt thin wires with the diameter of about 625 nm were welded onto In wires as substrates. The Pt wires on the In substrate were taken for the three-point bending test and potential drop test for determining their mechanical and electrical properties. Moreover, based on the manipulation technique, by twisting the Pt thin wire around a core wire, simply-supported micro-coils on electrode chips were successfully fabricated, and their utility as electromagnetic actuators was realized.

scholarly journals Additive Manufacturing-Based In Situ Consolidation of Continuous Carbon Fibre-Reinforced Polycarbonate

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2450
Author(s):  
Andreas Borowski ◽  
Christian Vogel ◽  
Thomas Behnisch ◽  
Vinzenz Geske ◽  
Maik Gude ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fibre ◽  
Bending Test ◽  
Thermoplastic Composites ◽  
Experimental Investigations ◽  
Material Structure ◽  
Three Point Bending ◽  
Continuous Fibre ◽  
Local Material

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

scholarly journals Experimental and Numerical simulation of a Three Point Bending Test of a Stainless Steel Beam

2021 ◽  
Vol 55 ◽  
pp. 1114-1121
Author(s):  
Daniel Jindra ◽  
Zdeněk Kala ◽  
Jiří Kala ◽  
Stanislav Seitl
Keyword(s):  
Numerical Simulation ◽  
Stainless Steel ◽  
Bending Test ◽  
Steel Beam ◽  
Three Point Bending

scholarly journals Fracture and Size Effect of PFRC Specimens Simulated by Using a Trilinear Softening Diagram: A Predictive Approach

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
A Priori ◽  
Plain Concrete ◽  
Specimen Size ◽  
Bending Test ◽  
Orientation Factor ◽  
Fibre Reinforced Concrete ◽  
Softening Function ◽  
Three Point Bending

The size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function. Nevertheless, in the case of polyolefin-fibre-reinforced concrete (PFRC), this is not directly applicable, since using only diagram cannot capture the material behaviour on elements with different sizes due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin-fibre-reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin-fibre-reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well-known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner and then compared with a previous experimental campaign in which PFRC notched specimens of different sizes were tested with a three-point bending test setup, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.

Experimental and Numerical Investigation of Critical Buckle Load of Composite Specimens

2015 ◽  
Vol 732 ◽  
pp. 85-90
Author(s):  
Lukáš Bek ◽  
Radek Kottner ◽  
Jan Krystek ◽  
Tomáš Kroupa
Keyword(s):  
Static Analysis ◽  
Glass Fibre ◽  
Large Deformations ◽  
Bending Test ◽  
Test Results ◽  
Beam Test ◽  
Three Point Bending ◽  
Box Beams ◽  
Buckle Beam ◽  
Thin Walled

Different carbon and glass fibre strips were subjected to the double clamp buckle beam test. Furthermore, thin-walled glass fibre box-beams were subjected to the three-point bending test. Results of experiments were compared to different numerical simulations using buckling analysis or static analysis considering large deformations.

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