Fatigue Behavior and Microstructure of Pt-20Ir Wire as Lead Conductor in Implantable Medical Device

2012 ◽  
Author(s):  
Bernard Q. Li ◽  
Kailynn Cho ◽  
Haitao Zhang
Keyword(s):  
Medical Device ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Surface Region ◽  
Electrical Signal ◽  
The Body ◽  
Implantable Medical Device ◽  
Near Surface ◽  
Cold Draw ◽  
The Wire

Pt-20Ir cold draw wire has been used as lead conductor in implantable medical devices. The lead is a medical device to transfer the electrical signal from a implanted stimulator to the body area for stimulating such as brain and neurological nerves. In this study, fatigue behavior and failure mechanism of Pt-20Ir wire was studied with rotary bending fatigue testing. The relations between the cyclic strain amplitude (ε) and the cycles to failure (N) were obtained and compared with MP35N wire which is the most commonly used metal wire as lead conductors. The results show Pt-20Ir cold drawn wire (0.102 mm) has a fatigue endurance strain limit of 0.18% which is significant lower than that of MP35N wire. Microstructure of Pt-20Ir cold draw wire was also analyzed. Results show that the grain size of in wire is elongated like bundled fiber structure. The texture of wire is strongly fiber textured and with a strong gradient from outside layer to center of the wire. Near surface region has <111> textured grain and around center region of the wire has <100> textured grain. The center of grain also has larger size than near surface.

Fatigue Behavior of Pt-20%Ir Coils Used as Implanted Electrodes in Medical Devices

2013 ◽  
Author(s):  
Haitao Zhang ◽  
Bernard Q. Li
Keyword(s):  
Medical Devices ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Curve ◽  
Electrical Signal ◽  
The Body ◽  
Stress And Strain ◽  
Analysis Software ◽  
Element Analysis ◽  
Implanted Electrodes

Pt-20%Ir coils were used in medical devices as conductors for the leads that transfer the electrical signal from an implanted stimulator to the area of the body (e.g., brain or nerves) to be stimulated. In this study, the fatigue behavior and failure mechanism of Pt-20%Ir coils was studied with axial fatigue testing. The stress and strain on the coils was analyzed with the non-linear FEA (finite element analysis) software ABAQUS. A strain vs. fatigue curve was obtained. A SEM (scanning electron microscope) was used to analyze the fatigue fracture surface of the samples.

EFFECT OF VARIOUS HEAT TREATMENT PROCESSES ON FATIGUE BEHAVIOR OF TOOL STEEL FOR COLD FORGING DIE

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5495-5502
Author(s):  
S. U. JIN ◽  
S. S. KIM ◽  
Y. S. LEE ◽  
Y. N. KWON ◽  
J. H. LEE
Keyword(s):  
Heat Treatment ◽  
Tool Steel ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Cryogenic Treatment ◽  
Testing Machine ◽  
Near Surface ◽  
Treatment Processes ◽  
R Ratio ◽  
Quenching And Tempering

Effects of various heat treatment processes, including "Q/T (quenching and tempering)", "Q/CT/T (Quenching, cryogenic treatment and tempering)", "Q/T (quenching and tempering) + Ti -nitriding" and "Q/CT/T (Cryogenic treatment and tempering) + Ti -nitriding", on S - N fatigue behavior of AISI D2 tool steel were investigated. The optical micrographs and Vicker's hardness values at near surface and core area were examined for each specimen. Uniaxial fatigue tests were performed by using an electro-magnetic resonance fatigue testing machine at a frequency of 80 Hz and an R ratio of -1. The overall resistance to fatigue tends to decrease significantly with Ti -nitriding treatment compared to those for the general Q/T and Q/CT/T specimens. The reduced resistance to fatigue with Ti -nitriding is discussed based on the microstructural and fractographic analyses.

scholarly journals Investigation of the boundary layer zone with an aerodynamic flow around an axisymmetric spindle-shaped body for solving conjugate problems of heat and mass transfer

2021 ◽  
Vol 2131 (2) ◽  
pp. 022028
Author(s):  
T Novoselova ◽  
L Tolmacheva ◽  
A Palii ◽  
J Akopdjanyan
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Conjugate Heat Transfer ◽  
Transfer Problem ◽  
Surface Region ◽  
The Body ◽  
Temperature Fields ◽  
Similarity Coefficients ◽  
Near Surface ◽  
Shaped Body

Abstract The article discusses the possibility of calculating the thickness of the boundary layer when flowing around an axisymmetric spindle-shaped body without using empirical similarity coefficients. For this, the use of physical analogy of processes is proposed. The necessary flow conditions are described. The two-dimensional Laplace equation is solved for the near-surface region of the laminar flow around the body, obtained by rotating a curve of a given shape. When solving the problems of conjugate heat transfer, the regularities of the interaction of the flow with the body surface are taken into account, which, as a result, is reduced to the joint solution of the boundary layer equations describing the flow field and the heat conduction equations describing the propagation of temperature fields inside and outside the body. In view of the complexity or impossibility of the analytical solution of such problems, it is customary to resort to numerical methods for solving these equations. Even the numerical solution of the conjugate heat transfer problem is associated with a huge number of calculations, the availability of computing power and significant time costs. Therefore, it is customary to solve such problems in a quasi-stationary approximation, which imposes certain restrictions on the scope of application

scholarly journals Effect of Thermomechanical Treatment on Structure and Functional Fatigue Characteristics of Biodegradable Fe-30Mn-5Si (wt %) Shape Memory Alloy

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3327
Author(s):  
Sergey Prokoshkin ◽  
Yury Pustov ◽  
Yulia Zhukova ◽  
Pulat Kadirov ◽  
Maria Karavaeva ◽  
...  
Keyword(s):  
Body Temperature ◽  
Shape Memory ◽  
Corrosion Fatigue ◽  
Hot Rolling ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Alloy System ◽  
The Body ◽  
Grain Structure ◽  
Air Atmosphere

The Fe-Mn-Si shape memory alloys are considered promising materials for the biodegradable bone implant application since their functional properties can be optimized to combine bioresorbability with biomechanical and biochemical compatibility with bone tissue. The present study focuses on the fatigue and corrosion fatigue behavior of the thermomechanically treated Fe-30Mn-5Si (wt %) alloy compared to the conventionally quenched alloy because this important functionality aspect has not been previously studied. Hot-rolled and water-cooled, cold-rolled and annealed, and conventionally quenched alloy samples were characterized by X-ray diffraction, transmission electron microscopy, tensile fatigue testing in air atmosphere, and bending corrosion fatigue testing in Hanks’ solution. It is shown that hot rolling at 800 °C results in the longest fatigue life of the alloy both in air and in Hanks’ solution. This advantage results from the formation of a dynamically recrystallized γ-phase grain structure with a well-developed dislocation substructure. Another important finding is the experimental verification of Young’s modulus anomalous temperature dependence for the studied alloy system, its minimum at a human body temperature, and corresponding improvement of the biomechanical compatibility. The idea was realized by lowering Ms temperature down to the body temperature after hot rolling at 800 °C.

Preparation of cross-sectional samples for near-surface TEM studies

1987 ◽  
Vol 45 ◽  
pp. 380-381
Author(s):  
R.C. Dickenson ◽  
K.R. Lawless
Keyword(s):  
Standard Sample ◽  
Surface Region ◽  
Specimen Preparation ◽  
Thick Sheet ◽  
Drill Bit ◽  
Sample Holder ◽  
Metal Interface ◽  
Cross Sectional ◽  
Near Surface ◽  
Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

Microstructural changes of Aluminum Nitride after laser irradiation and electroless copper deposition

1994 ◽  
Vol 52 ◽  
pp. 636-637
Author(s):  
S. Cao ◽  
A. J. Pedraza ◽  
L. F. Allard
Keyword(s):  
Aluminum Nitride ◽  
Laser Irradiation ◽  
Electroless Deposition ◽  
Thermal Evaporation ◽  
Surface Region ◽  
Near Surface ◽  
Laser Patterning ◽  
Electroless Copper ◽  
Excimer Laser Irradiation ◽  
Laser Effect

Excimer-laser irradiation strongly modifies the near-surface region of aluminum nitride (AIN) substrates. The surface acquires a distinctive metallic appearance and the electrical resistivity of the near-surface region drastically decreases after laser irradiation. These results indicate that Al forms at the surface as a result of the decomposition of the Al (which has been confirmed by XPS). A computer model that incorporates two opposing phenomena, decomposition of the AIN that leaves a metallic Al film on the surface, and thermal evaporation of the Al, demonstrated that saturation of film thickness and, hence, of electrical resistance is reached when the rate of Al evaporation equals the rate of AIN decomposition. In an electroless copper bath, Cu is only deposited in laser-irradiated areas. This laser effect has been designated laser activation for electroless deposition. Laser activation eliminates the need of seeding for nucleating the initial layer of electroless Cu. Thus, AIN metallization can be achieved by laser patterning followed by electroless deposition.

A Fluidic Vibrational Energy Harvester for Implantable Medical Device Applications

2017 ◽  
Vol 137 (6) ◽  
pp. 152-158
Author(s):  
Satoshi Inoue ◽  
Takuya Takahashi ◽  
Momoko Kumemura ◽  
Kazunori Ishibashi ◽  
Hiroyuki Fujita ◽  
...  
Keyword(s):  
Medical Device ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Implantable Medical Device ◽  
Device Applications

Fatigue of Unidirectional Cord-Rubber Composites

1999 ◽  
Vol 27 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Y. Liu ◽  
Z. Wan ◽  
Z. Tian ◽  
X. Du ◽  
J. Jiang ◽  
...  
Keyword(s):  
Damage Accumulation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Testing System ◽  
Rubber Composites ◽  
Cycle Frequency ◽  
Periodic Loading ◽  
Fatigue Damage Accumulation ◽  
Rubber Composite

Abstract A fatigue testing system is established with which the real-time recording of stress, strain, temperature, and hysteresis loss of rubbers or cord-rubber composite specimens subjected to periodic loading or extension can be successfully carried out. Several problems are connected with the experimental study of the fatigue of rubber composites. In constant extension cycling, the specimen becomes relaxed because of the viscoelasticity of rubber composites, and the imposed tension-tension deformation becomes complex. In this method, the specimen is unlikely to fail unless the imposed extensions are very large. Constant load cycling can avoid the shortcomings of constant extension cycling. The specially designed clamps ensure that the specimen does not slip when the load retains a constant value. The Deformation and fatigue damage accumulation processes of rubber composites under periodic loading are also examined. Obviously, the effect of cycle frequency on the fatigue life of rubber composites can not be ignored because of the viscoelasticity of constituent materials. The increase of specimen surface temperature is relatively small in the case of 1 Hz, but the temperature can easily reach 100°C at the 8 Hz frequency. A method for evaluating the fatigue behavior of tires is proposed.

scholarly journals Computational Modeling of Vortex Generators for Turbomachinery

2002 ◽  
Author(s):  
R. V. Chima
Keyword(s):  
Computational Models ◽  
Body Force ◽  
Secondary Flows ◽  
The Body ◽  
Vortex Generators ◽  
Force Model ◽  
Suction Surface ◽  
Near Surface ◽  
Compressor Rotor ◽  
Surface Particle

In this work computational models were developed and used to investigate applications of vortex generators (VGs) to turbomachinery. The work was aimed at increasing the efficiency of compressor components designed for the NASA Ultra Efficient Engine Technology (UEET) program. Initial calculations were used to investigate the physical behavior of VGs. A parametric study of the effects of VG height was done using 3-D calculations of isolated VGs. A body force model was developed to simulate the effects of VGs without requiring complicated grids. The model was calibrated using 2-D calculations of the VG vanes and was validated using the 3-D results. Then three applications of VGs to a compressor rotor and stator were investigated: 1. The results of the 3-D calculations were used to simulate the use of small casing VGs used to generate rotor preswirl or counterswirl. Computed performance maps were used to evaluate the effects of VGs. 2. The body force model was used to simulate large partspan splitters on the casing ahead of the stator. Computed loss buckets showed the effects of the VGs. 3. The body force model was also used to investigate the use of tiny VGs on the stator suction surface for controlling secondary flows. Near-surface particle traces and exit loss profiles were used to evaluate the effects of the VGs.

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