Sealing Performance of Pipe Flange Connections With Shape Memory Alloy Gaskets Under Internal Pressure

2004 ◽  
Author(s):  
Teruhisa Tatsuoka ◽  
Yoshio Takagi ◽  
Toshiyuki Sawa
Keyword(s):  
Elastic Modulus ◽  
Numerical Analysis ◽  
Low Temperature ◽  
Shape Memory ◽  
Strain Behavior ◽  
Sealing Performance ◽  
Low Elastic Modulus ◽  
Thermal Expansion Effect ◽  
Expansion Effect

Due to the long-term durability and the excellent resistance to aging degradation, metal gaskets are expected to give a longer life compared to conventional polymer gaskets. However, the nature of high elastic modulus of the metal reduces the sealing performance at interface. On the other hand, shape memory alloys (SMA) like nickel-titanium (Ni-Ti) alloy have a super elasticity and an excellent deformation capability with relatively low elastic modulus as a metal. Therefore, Ni-Ti SMA is expected to show an excellent performance as a gasket. In order to evaluate the applicability of Ni-Ti SMA to gasket, experimental and numerical analysis were conducted in this study. As an experimental evaluation, the new gasket constants and the tightness parameter proposed by PVRC (Pressure Vessel Research Council) were measured by the leakage tests. The constants and the tightness parameter of Ni-Ti SMA gasket were superior to those of aluminum gasket. The numerical analysis revealed that the clamping temperature highly affected on the performance of Ni-Ti SMA gasket because the stress-strain behavior of Ni-Ti SMA strongly depended on the temperature. Since the Ni-Ti SMA has a softer phase at low temperature, e.g. less than 11°C (As point), the flange connection initially clamped at low temperature showed a higher sealing performance. In addition, the heat cycle test with the cycle of the initial clamp temperature (0 or 20°C) to 40°C also suggested that the lower clamp temperature yielded a higher contact force due to the thermal expansion effect.

Analysis on the Martensitic Transformation in the Ti-xNb Alloys Using a Phenomenological Theory

2007 ◽  
Vol 124-126 ◽  
pp. 1669-1672 ◽  
Author(s):  
Hi Won Jeong ◽  
Seung Eon Kim ◽  
Chang Yong Jo ◽  
Yong Tae Lee ◽  
Joong Kuen Park
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Titanium Alloys ◽  
Martensitic Transformations ◽  
Phenomenological Theory ◽  
Transition Elements ◽  
Low Elastic Modulus ◽  
Diffraction Peaks

The titanium alloys containing the Nb transition elements have been investigated as the Ni-free shape memory and the biomedical alloys with a low elastic modulus. The mechanical properties of the alloys depended upon the meta-stable phases like the α`, α``, ω. To study the martensitic transformations from the β to α`` or α` the Ti-xNb (x=0 to 40 wt%) alloys were melted into the button type ingots using a VAR, and followed by the water-quenching after the soaking at 1000oC for 2hrs. The crystallography of the martensitic phases in the water-quenched alloys was analyzed using a XRD. The diffraction peaks of the orthorhombic martensites were identified by the crystallographic relationship with the bcc matrix. The lattice parameters of the orthorhombic martensites were varied continuously with the contents of the Nb elements. The martensitic transformations of the alloys were studied using the phenomenological theory of Bowles and Mackenzie.

Temperature Dependent Characteristics of 1D Photonic Crystal with Defects

2012 ◽  
Vol 535-537 ◽  
pp. 1299-1303
Author(s):  
Hui Bo Wang ◽  
Kai Tong ◽  
Mei Ting Wang ◽  
Chao Cong Guo
Keyword(s):  
High Temperature ◽  
Photonic Crystal ◽  
Low Temperature ◽  
Linear Relationship ◽  
Temperature Characteristic ◽  
Central Wavelength ◽  
Temperature Changes ◽  
Icp Etching ◽  
Thermal Expansion Effect ◽  
Expansion Effect

When the temperature is changed, due to the influence of the thermal expansion effect and thermo-optic effect, the thickness and refractive index of each layer of medium of photonic crystal will be Varied. As shown by optical resonators theory, the drift amount of the wavelength has a linear relationship with the variation of temperature. The electron beam lithography technology (EBL) and induction coupling plasma(ICP) etching were used for making the PCs with 1550nm central wavelength. An experiment mode is constructed for analyzing temperature characteristic of one-dimensional PCs, and then PCs is experimented at low temperature and high temperature. It can be found by experiment that, as the temperature changes, the central wavelength of photonic crystal has a linear relationship with the temperature, the drift amount of central wavelength at the low temperature is 0.072nm/°C,the drift amount at the high temperature is 0.076nm/°C,and the 3dB bandwidth of transmission spectrum of photonic crystal has no significant change, the spectral shape is changed very little.

The characterization of shape memory effect for low elastic modulus biomedical β-type titanium alloy

2010 ◽  
Vol 61 (5) ◽  
pp. 535-541 ◽  
Author(s):  
Liqiang Wang ◽  
Weijie Lu ◽  
Jining Qin ◽  
Fan Zhang ◽  
Di Zhang
Keyword(s):  
Titanium Alloy ◽  
Elastic Modulus ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Low Elastic Modulus

The Effect of the Thermal Expansion Coefficient on the Sealing Performance of Pipe Flange Connections With NiTi Shape Memory Alloy Gaskets

2006 ◽  
Author(s):  
Yoshio Takagi ◽  
Teruhisa Tatsuoka ◽  
Toshiyuki Sawa
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Research Council ◽  
Nickel Titanium ◽  
Niti Shape Memory Alloy ◽  
Ti Alloy ◽  
Sealing Performance

Due to the long-term durability and the excellent resistance to aging degradation, metal gaskets are expected to endure a longer life compared to conventional polymer gaskets. However, the nature of high elastic modulus of the metal reduces the sealing performance at interface. The authors have paid attention to the super elasticity of the shape memory alloys like Nickel-Titanium (Ni-Ti) alloy and evaluated its applicability to a gasket. In the process, leakage tests of the flange connections with Ni-Ti alloy gaskets were done and the sealing performance was evaluated with the new gasket constants and the tightness parameter proposed by PVRC (Pressure Vessel Research Council, ASME). The results revealed that Ni-Ti alloy gaskets showed a superior sealing performance to the conventional aluminum gasket. However, the thermal expansion coefficient of Ni-Ti alloy is smaller than that of stainless steel of which the flange is made. The increase in temperature of the flange like 20 °C to 40 °C accordingly induced a slight degradation of the sealing performance. In this paper, the effect of the change in temperature on the sealing performance of the pipe flange connections with Ni-Ti alloy gasket was numerically evaluated with the measured thermal expansion coefficient. Moreover, the effect of the clamped temperature on the sealing performance was evaluated taking into account the temperature dependence of the mechanical properties of Ni-Ti alloy.

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.

Influence of Cold Work in the Elastic Modulus of the Ti-16.2Hf-24.8Nb-1Zr Alloy Characterized by Instrumented Nanoindentation

2009 ◽  
Vol 423 ◽  
pp. 113-118 ◽  
Author(s):  
Marta González ◽  
J. Peña ◽  
Jose Maria Manero ◽  
F.J. Gil
Keyword(s):  
Elastic Modulus ◽  
Shape Memory ◽  
Load Transfer ◽  
Cold Work ◽  
Elastic Response ◽  
Vacuum Arc ◽  
Damping Capacity ◽  
Heat Treated ◽  
Low Elastic Modulus ◽  
Cold Worked

Nowadays, β type Ti-based alloys have been developed for load transfer clinical applications due to their superelasticity, shape memory effect, low elastic modulus and high damping capacity [1]. These properties promote bone regeneration and make them promising candidates for being used in load transfer implantology. The objective of the present work is to achieve a material with shape memory properties and/or low elastic modulus. The influence of cold work on the thermoelastic martensitic transformation and elastic modulus of the Ti-16.2Hf-24.8Nb-1Zr alloy has been investigated to determine optimal conditions. The homogenized vacuum arc melted button was heat treated at 1100°C during 2 hours and quenched. Samples of each alloy were microstructurally and mechanically characterized after being cold rolled from 5 up to 95%. The elastic response for each condition was evaluated by instrumented nanoindentation by using a Berkovich tip and a spherical tip. A decrease in elastic modulus was observed when increasing the cold work percentage. The lowest value, 44 GPa, similar to that of cortical bone, was found in the 95% cold worked condition.

Stress Analysis and Sealing Performance of Pipe Flange Connections With NiTi Shape Memory Alloy Gasket

2007 ◽  
Author(s):  
Yoshio Takagi ◽  
Teruhisa Tatsuoka ◽  
Naoki Kawasaki ◽  
Toshiyuki Sawa
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Niti Alloy ◽  
Fem Analysis ◽  
Effect Of Temperature ◽  
Niti Shape Memory Alloy ◽  
3D Fem ◽  
Sealing Performance

Due to the long-term durability and the excellent resistance to aging degradation, metal gaskets are expected to give a longer life compared to conventional polymer gaskets. However, the nature of high elastic modulus of the metal reduces the sealing performance at interface. Nickel-Titanium shape memory alloy (NiTi alloy) shows an excellent elasticity and is expected to be applicable as a gasket. The authors have already evaluated the sealing performance of the pipe flange connections with NiTi gaskets. The results revealed that NiTi alloy showed a superior sealing performance to the conventional aluminum gasket. However, the sealing performance of the connection depended on the ambient temperature due to the change in physical properties like the elastic modulus and the thermal expansion coefficient of NiTi alloy. In this paper, the stress distribution was analyzed with 3D FEM and the effect of temperature in the sealing performance was evaluated. In the analysis, the particular element code was adopted for analyzing the deformation behavior of NiTi alloy gasket. The elements worked well in the analysis and helped to evaluate the sealing behavior of the flange connections. According to the analysis, the gasket contact stress decreased as increasing the temperature because of the lower thermal expansion of NiTi alloy than that of austenitic stainless steel of which the flange and bolt material were made. On the other hand, the FEM analysis suggested that the increment of elastic modulus of NiTi alloy compensate the reduction of compression strain of the gasket due to the difference of thermal expansion between gasket and flange. As a result of the ex-experimental study and FE analysis, the recommendable assembling process for NiTi alloy gasket was proposed.

scholarly journals Evaluation of Sealing Performance of Pipe Flange Connections for Low Temperature Fluids by Numerical Analysis

2019 ◽  
Vol 54 (5) ◽  
pp. 758-764
Author(s):  
Toshimichi Fukuoka ◽  
Masataka Nomura ◽  
Ami Nakada
Keyword(s):  
Numerical Analysis ◽  
Low Temperature ◽  
Sealing Performance

Study of New Multifunctional Shape Memory and Low Elastic Modulus Ni-Free Ti Alloys

2008 ◽  
Vol 39 (4) ◽  
pp. 742-751 ◽  
Author(s):  
M. Arciniegas ◽  
J.M. Manero ◽  
J. Peña ◽  
F.J. Gil ◽  
J.A. Planell
Keyword(s):  
Elastic Modulus ◽  
Shape Memory ◽  
Ti Alloys ◽  
Low Elastic Modulus

scholarly journals Experimental Investigation for Tensile Performance of GFRP-Steel Hybridized Rebar

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Dong-Woo Seo ◽  
Ki-Tae Park ◽  
Young-Jun You ◽  
Sang-Yoon Lee
Keyword(s):  
Elastic Modulus ◽  
Concrete Structures ◽  
Tensile Tests ◽  
Test Results ◽  
Building Technology ◽  
Gfrp Bars ◽  
Low Elastic Modulus ◽  
Tensile Performance ◽  
The Individual

Tensile performance of the recently developed “FRP Hybrid Bar” at Korea Institute of Civil Engineering and Building Technology (KICT) is experimentally evaluated by the authors. FRP Hybrid Bar is introduced to overcome the low elastic modulus of the existing GFRP bars to be used as a structural member in reinforced concrete structures. The concept of material hybridization is applied to increase elastic modulus of GFRP bars by using steel. This hybridized GFRP bar can be used in concrete structures as a flexural reinforcement with a sufficient level of elastic modulus. In order to verify the effect of material hybridization on tensile properties, tensile tests are conducted. The test results for both FRP Hybrid Bar and the existing GFRP bars are compared. The results indicate that the elastic modulus of FRP Hybrid Bar can be enhanced by up to approximately 250 percent by the material hybridization with a sufficient tensile strength. To ensure the long-term durability of FRP Hybrid Bar to corrosion resistance, the individual and combined effects of environmental conditions on FRP Hybrid Bar itself as well as on the interface between rebar and concrete are currently under investigation.

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