scholarly journals Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: stress-strain tests

2013 ◽  
Vol 18 (4) ◽  
pp. 35-42 ◽  
Author(s):  
Marco Abdo Gravina ◽  
Ione Helena Vieira Portella Brunharo ◽  
Cristiane Canavarro ◽  
Carlos Nelson Elias ◽  
Cátia Cardoso Abdo Quintão
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Orthodontic Treatment ◽  
Testing Machine ◽  
The Other ◽  
Lower Percentage ◽  
Machine Model ◽  
Military Institute ◽  
The Military

OBJECTIVE: This research aimed to compare, through traction tests, eight types of superelastic and heat-activated NiTi archwires, by six trade companies (GAC, TP, Ormco, Masel, Morelli and Unitek) to those with addition of copper (CuNiTi 27ºC and 35ºC, Ormco). METHODS: The tests were performed in an EMIC mechanical testing machine, model DL10000, capacity of 10 tons, at the Military Institute of Engineering (IME). RESULTS: The results showed that, generally, heat-activated NiTi archwires presented slighter deactivation loadings in relation to superelastic. Among the archwires that presented deactivation loadings biologically more adequate are the heat-activated by GAC and by Unitek. Among the superelastic NiTi, the CuNiTi 27ºC by Ormco were the ones that presented slighter deactivation loadings, being statistically (ANOVA) similar, to the ones presented by the heat-activated NiTi archwires by Unitek. When compared the CuNiTi 27ºC and 35ºC archwires, it was observed that the 27ºC presented deactivation forces of, nearly, ⅓ of the presented by the 35ºC. CONCLUSION: It was concluded that the CuNiTi 35ºC archwires presented deactivation loadings biologically less favorable in relation to the other heat-activated NiTi archwires, associated to lower percentage of deformation, on the constant baselines of deactivation, showing less adequate mechanical behavior, under traction, in relation to the other archwires.

Mechanical Behavior of Alumina Toughened Zirconia Nanocomposites with Different Alumina Additions

2014 ◽  
Vol 96 ◽  
pp. 61-66 ◽  
Author(s):  
Luis Antonio Díaz ◽  
Sergio Rivera ◽  
Adolfo Fernández ◽  
Anna Okunkova ◽  
Yu.G. Vladimirov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crack Propagation ◽  
Mechanical Behavior ◽  
Crack Growth ◽  
Disperse Phase ◽  
Subcritical Crack Growth ◽  
The Other ◽  
Structural Components ◽  
Monolithic Ceramics

ZrO2 and Al2O3 are monolithic ceramics used today in a wide variety of structural components. However, both materials present important drawbacks for some specific applications. In the case of Al2O3, its moderate strength (500 MPa) and toughness (4 MPa.√m) makes it unsuitable for high loading conditions. On the other hand, ZrO2 presents higher strength and toughness values (900 MPa and 6 MPa.√m) than Al2O3 but it is a material limited in its long-term behaviour due to its bad response to hydrothermal ageing and a pronounced tendency for subcritical crack growth. Due to this fact, ceramic nanocomposites made of Al2O3 and ZrO2 (ATZ and ZTA) have been developed in the last years in order to overcome the main drawbacks of the monolithic materials as they can combine the properties of both, strong and tough materials, simultaneously, with null ageing and even higher biocompatibility. In this work, several amounts of Al2O3 disperse phase (15, 35 and 50 vol %) were added to one ZrO2 matrix (CeO2 - 10 mol %) in order to see their effect on the mechanical properties, subcritical crack propagation and long-term reliability.

scholarly journals Static and Dynamic Tensile Mechanical Behavior of Polyvinyl Chloride Elastomers with Different Shore Hardness

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jingfa Lei ◽  
Yan Xuan ◽  
Tao Liu ◽  
Feiya Duan ◽  
Zhan Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Polyvinyl Chloride ◽  
Mechanical Characteristics ◽  
Testing Machine ◽  
Tensile Load ◽  
Small Error ◽  
Polymer Materials ◽  
Design Development ◽  
Shore Hardness

An experiment on the static and dynamic tensile mechanical properties of polyvinyl chloride (PVC) elastomers is conducted using an Instron-5943 universal testing machine and an improved Split Hopkinson Tensile Bar to study the dynamic tensile mechanical properties of PVC elastomer materials. The stress-strain curves of PVC materials with three types of Shore hardness (57A, 52A, and 47A) under the strain rates of 0.1 s−1 and 400 ∼ 1800 s−1 are obtained. Results show that the mechanical behavior of PVC elastomer materials with different Shore hardness has remarkable linear elastic characteristics under the action of quasistatic tensile load. It has substantial sensitivity to strain rate and viscoelastic mechanical characteristics under the action of dynamic tensile load. The Zhu–Wang–Tang nonlinear viscoelastic constitutive model is used to characterize the viscoelastic mechanical characteristics with small error. This paper can provide theoretical model and method support for the design, development, production, and reliability analysis of PVC elastomers and other soft polymer materials.

Synthesis and Characterisation of New Superelastic and Low Elastic Modulus Ti-Nb-X Alloys for Biomedical Application

2011 ◽  
Vol 409 ◽  
pp. 170-174
Author(s):  
A. Ramarolahy ◽  
Philippe Castany ◽  
Thierry Gloriant ◽  
Frédéric Prima ◽  
P. Laheurte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Shape Memory ◽  
Biomedical Application ◽  
The Other ◽  
Alloying Element ◽  
Low Elastic Modulus ◽  
Superelastic Behavior ◽  
Good Biocompatibility

Ti-Nb based alloys are well known to their good mechanical properties, shape memory effect, superelasticity, as well as good biocompatibility. The Ti-24Nb (at%) binary alloy presents a shape memory behavior and low elastic modulus. Our study is focused on the improvement of their mechanical properties by adding a third alloying element (oxygen, nitrogen or silicon). Addition of 0.5 at% of N or O modifies drastically the mechanical behavior of Ti-24Nb alloy that exhibits superelastic behavior instead of shape memory one. On the other hand, addition of 0.5 at% of Si increased yield strength of the Ti-24Nb shape memory alloy.

scholarly journals Three Palatal Arches Used to Correct Posterior Dental Crossbites

2006 ◽  
Vol 76 (6) ◽  
pp. 1047-1051 ◽  
Author(s):  
Fernando Lima Martinelli ◽  
Priscilla Sobral Couto ◽  
Antonio Carlos Oliveira Ruellas
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Statistical Analysis ◽  
Orthodontic Treatment ◽  
Elasticity Modulus ◽  
Steel Wire ◽  
Testing Machine ◽  
Stainless Steel Wire ◽  
Quad Helix ◽  
One Way Anova

Abstract Objective: To assess the force, resilience, and elasticity modulus produced by the Coffin appliance, “W” arch, and quad-helix made with 0.032-inch and 0.036-inch stainless steel wire. Materials and Methods: Two groups of 15 arches were made as Coffin appliances, two groups of 15 arches were made as “W” arches, and two groups of 15 arches were made as quad-helices. One group of each appliance was formed in 0.032-inch and one group in 0.036-inch stainless steel wire. All arches (6 groups of 15 each) were submitted to compression trials in the mechanical testing machine EMIC DL-10000, simulating 5-, 8-, 10-, and 12-mm activation. The force and resilience means received a one-way ANOVA statistical analysis. Results: The results showed that the mechanical properties depended on the shape of the appliance, the diameter of the wire used, and the amount of activation. Conclusions: The three appliances assessed produce appropriate forces for orthodontic treatment as long as they are correctly planned during clinical application.

Research on Mechanical Properties of TiNi Shape Memory Alloy Wires Reinforced Al Matrix Composite Material

2015 ◽  
Vol 1120-1121 ◽  
pp. 502-506
Author(s):  
Sheng Nan Yang ◽  
Su Yuan Yang
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Volume Fraction ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Hopkinson Pressure Bar ◽  
Pressing Method ◽  
Pressure Bar ◽  
Al Matrix

TiNi/Al shape memory alloy (SMA) composite was fabricated by a vacuum hot-pressing method to investigate the phase , microstructure and mechanical properties. Phase analysis was conducted by XRD . Interface bonding between TiNi wire and Al matrix was observed by using SEM and EDS. Quasi-static and dynamic compressive mechanical properties of the composite were investigated by using electronic universal testing machine (INSTRON5985) and Split-Hopkinson Pressure Bar (SHPB),respectively. The experiment results show that new phases Ni4Ti3 and Ti2Ni precipitined from TiNi wire. Interfacial reactions occurred at the bonding between matrix and TiNi wire, creating a diffusion layer about 2μm thick. Both quasi-static and dynamic compressive mechanical properties are anisotropic , and the degree of the anisotropy increased with the increase of TiNi volume fraction.

Effects of Moisture Exposure on the Mechanical Behavior of Polymer Encapsulants in Microelectronic Packaging

2013 ◽  
Author(s):  
Nusrat J. Chhanda ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Testing Machine ◽  
Adsorbed Water ◽  
Ultimate Tensile Stress ◽  
Stress Strain ◽  
Uniaxial Test ◽  
Organic Structure ◽  
Strain Behavior ◽  
Humidity Chamber

Polymer encapsulants exhibit evolving properties that change significantly with environmental exposures such as moisture uptake, isothermal aging and thermal cycling. In this study, the effects of moisture adsorption on the stress-strain behavior of a polymer encapsulant were evaluated experimentally. The uniaxial test specimens were exposed in an adjustable thermal and humidity chamber to combined hygrothermal exposures at 85 °C/85% RH for various durations. After moisture preconditioning, a microscale tension-torsion testing machine was used to evaluate the complete stress-strain behavior of the material at several temperatures. It was found that moisture exposure caused plasticization and strongly reduced the mechanical properties of the encapsulant including the initial elastic modulus and ultimate tensile stress. Reversibility tests were also conducted to evaluate whether the degradations in the mechanical properties were recoverable. Upon fully redrying, the polymer was found to recover most but not all of its original mechanical properties. As revealed by FTIR, some of the adsorbed water had been hydrolyzed in the organic structure of the epoxy-based adhesive, causing permanent changes to the mechanical behavior.

scholarly journals High-speed camera test of newly developed igniter’s charges for artillery rounds

2021 ◽  
Vol 2090 (1) ◽  
pp. 012129
Author(s):  
A Plachá ◽  
J Recko
Keyword(s):  
High Speed ◽  
The Other ◽  
Ignition Process ◽  
High Speed Camera ◽  
Test Results ◽  
Black Powder ◽  
Time To Ignition ◽  
Military Institute ◽  
The Military

Abstract The article presents the results of the high-speed camera test of newly developed igniter’s charges for artillery rounds. The test was performed to take a closer look at the ignition process of mixtures, that is, to check the time-to-ignition of samples, and to assess the presence and quantity of solid igniting particles (if any). Five compositions were tested: Three of them contained the new igniter’s charges developed by the Military Institute of Armament Technology, and the other two contained black powder in different granularity classes as a comparison mixture. This article presents the collated test results.

scholarly journals EFFECTS OF THE HEAT TREATMENT ON THE MECHANICAL PROPERTIES OF 6201 ALUMINIUM ALLOY WIRE

2019 ◽  
Vol 57 (3A) ◽  
pp. 11 ◽  
Author(s):  
Khanh Cong Huynh
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminium Alloy ◽  
Tensile Testing ◽  
Solution Heat Treatment ◽  
Testing Machine ◽  
Machine Model ◽  
Tensile Testing Machine ◽  
Alloy Wire ◽  
Heat Treated

Type 6201 aluminium alloy wires are produced by drawing 4.7 mm diameter billet-on-billet extruded redraw rod down to 2.7 mm diameter wires. Before drawing, the first group of redraw rod coils was annealed at 480oC for 4 hours to reduce the hardness of the redraw rod. The second group of redraw rod coils was drawn without annealing. With each group of redraw rod, after drawing, some wire coils were solution heat treated, then artificially aged or naturally aged. The other wire coils were artificially aged or naturally aged without solution heat treatment. Mechanical properties of the wires were assessed by a tensile testing machine (model UTM-1000)With suitable aging temperature and aging time, wires produced from each group of redraw rod coils with or without solution heat treatment attain tensile requirements of ASTM B398, but wires produced with solution heat treatment attain higher elongation than wires produced without solution heat treatment.

Fabrication and Properties of Shape Memory Polyurethane Surface Modified Vapor Grown Carbon Nanofiber Composites

2011 ◽  
Vol 239-242 ◽  
pp. 855-859
Author(s):  
Hao Cen ◽  
Shan Li ◽  
Ming Liang Du ◽  
Ya Qin Fu
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Shape Memory ◽  
Coupling Agent ◽  
Carbon Nanofiber ◽  
Sol Gel ◽  
Testing Machine ◽  
Dynamic Mechanical ◽  
Sol Gel Process ◽  
Shape Memory Polyurethane

Shape memory polyurethane (SMPU)/Vapor grown carbon nanofibers (VGCNF) composites with different surface functionalized method were prepared via sol-gel process. The structure and properties of the composites were investigated by scanning electron microscopy (SEM), universal testing machine, and dynamic mechanical analysis (DMA). The results show that the dispersion of VGCNF with surface modification in matrix is better than that of pristine. The mechanical properties of the composites with VGCNF modified by concentrated nitric acid deteriorated substantially. However, both the tensile strength and elongation at break of the composites combined surface modification of silane coupling agent and sol-gel method increased obviously. The substantially improved mechanical properties are mainly attributed to the cross-link between coupling agent and the network structure of SiO2produced during the sol-gel process. The DMA analysis suggests that the surface treatment of the VGCNF exhibit obviously effect on the dynamic mechanical properties of the composites.

Investigate Mechanical Behavior of Gold Nanowire with Defect

2013 ◽  
Vol 481 ◽  
pp. 49-54
Author(s):  
Jia Lin Tsai ◽  
Cheng Fong Hong
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Mechanical Behavior ◽  
Cross Section ◽  
Md Simulation ◽  
The Other ◽  
Gold Nanowires ◽  
Gold Nanowire ◽  
Section Size ◽  
The Cross

This study aims to investigate the mechanical properties of gold nanowires using molecular dynamics (MD) simulation. The effects of the cross section size and the defects on the stress strain curves of the nanowires are examined. Moreover, the inception as well as the processing of dislocationin the nanowire is accounted by means of the centro-symmetry parameter and meanwhile, the energy variation during the dislocation is calculated. Results indicated for the pristine gold nanowire, as the cross section size increases, Youngs modulus increases, but the yielding stress decreases accordingly. Once the ultimate linear point is attained, the dislocation takes place abruptly from the nanowire surfaceand extended along the {111} planes. On the other hand, for the nanowire with defect, it was found that the dislocation is initiated from the defect which can significantlyreduce the yielding stress of the nanowires.

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