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

Author(s):  
Haitao Zhang ◽  
Bernard Q. Li

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.

Author(s):  
Bernard Q. Li ◽  
Kailynn Cho ◽  
Haitao Zhang

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.


2012 ◽  
Vol 538-541 ◽  
pp. 2681-2684
Author(s):  
Zhi Cheng Huang

Took a type of ceramics for daily use vertical type high pressure grouting machine as the object of study, study the stress and strain of its upper and lower mould plates. Established their 3D model by CAD software Pro-E, and then import them into finite element analysis software to analysis the value and distribution of the stress and strain. The analysis results can provide some reference for design, and have some engineering and practical value.


Author(s):  
Justin Karl ◽  
Ali P. Gordon

Contemporary computing packages handle a wide variety of stress analysis types, but are yet to provide an optimal way to handle certain load cases and geometries. Blades in gas turbine systems, for instance, undergo repetitive thermal and mechanical load cycles of varied shape and phasing. Complexly-shaped airfoils create non-uniform stress paths that exacerbate the problem of FEA software attempting to determine the correct states of stress and strain at any point during the load history. This research chronicles the update and integration of Miller’s original viscoplasticity model with ANSYS finite element analysis software. Elevated temperature strain-controlled LCF and strain-controlled TMF loadings were applied to single-element, uniaxial simulation runs and the results were then compared to data from duplicate experimental testing. Initial findings indicate that the model maintains significant accuracy through several cycles, but longer tests produce varying error in hysteretic response. A review of the modernized implementation of Miller’s viscoplasticity model is presented with a focus on modifications that may be used to improve future results.


2010 ◽  
Vol 148-149 ◽  
pp. 1639-1642
Author(s):  
Jian Feng Xie

The stresses and strains on the protected FBG and protected layer under varied temperature were analyzed in theory. In order to verify the theoretical analysis of stress and strain,a finite element analysis software(ANSYS) was used to simulate the stresses and strains on the protected FBG and protected layer. Both simulation and theoretical analysis are show that the strain and stress on protected layer in r direction decreases with the increasing of radius(r), while the strain and stress in direction increases with the increasing of radius(r) . The results of theoretical analysis matches the ones form simulations well.


2014 ◽  
Vol 602-605 ◽  
pp. 709-712
Author(s):  
Jin Hong Ma ◽  
Bin Tao ◽  
Xiao Han Yao

Y-Type rolling mill with three roller is a new kind of wire mill.The three-dimensional models of rolling are established by Pro/E. Based on the finite element analysis software ANSYS/LS-DYNA, the rolling process of wire by Y-type rollers is simulated. The rolling piece movement is analysed. Stress and strain of Y-type roller are also analysed.


2010 ◽  
Vol 148-149 ◽  
pp. 1634-1638
Author(s):  
Jian Feng Xie

After FBG was protected and embedded into cement mortar, the stresses and strains on the FBG ,protected layer and cement mortar under varied temperature were analyzed in theory. In order to verify the theoretical analysis of stress and strain,a finite element analysis software(ANSYS)was used to simulate the stresses and strains on the FBG ,protected layer and cement mortar. The results of theoretical analysis matches the ones form simulations well.


2013 ◽  
Vol 690-693 ◽  
pp. 164-167
Author(s):  
Xiao Long Hu ◽  
Lian Fei Tan ◽  
Qing Xuan Wang

This paper present that experimental research on the fatigue behavior of beam with Q345c steel corrugated webs. There are four test specimens with different structural feature will be tested in three-point bending to load by Shinmadzu 4890 fatigue testing machine. Moreover, the finite-element analysis will be used to simulate the fatigue behavior of common beam with corrugated steel web. Weld will be our focus on importance object.


2012 ◽  
Vol 164 ◽  
pp. 317-321
Author(s):  
Zhi Cheng Huang

In order to study the stress and strain of front and back mould plates of high pressure grouting machine, this paper took a type of ceramics for daily use horizontal type high pressure grouting machine as the object of study. Established its CAD model and analysed it with finite element analysis software. The analysis results can provide a reference for design, and have some engineering and practical value.


2009 ◽  
Vol 417-418 ◽  
pp. 77-80
Author(s):  
Hui Min Zhou ◽  
Qing Fen Li ◽  
Yu Feng Zheng ◽  
Li Li

Nickel-titanium alloy are extensively used in engineering and biomedical fields for their excellent properties of shape-memory, super-elasticity and biocompatibility. Their fatigue performance has been attracted increasingly attention, because they are often used under cyclic conditions. In this paper, the ultrasonic fatigue behavior of nickel-titanium endodontic files under unconstrained condition has been studied using the self-designed ultrasonic fatigue testing equipment. The vibration and harmonious response properties of nickel-titanium endodontic files are also analyzed using finite element method. Experimental results show that the average ultrasonic fatigue life of nickel-titanium endodontic files under unconstrained conditions is more than 108. Fracture of the files always occurred at the position about 2 -3 mm near the file tip. Results of finite element analysis show that the maximum stress of the nickel-titanium endodontic files located at the position about 2 -3 mm near the file tip, where is prone to generate fatigue cracks. The results of finite element analysis are consistent with the experimental results. The scanning electronic microscope (SEM) results show that the ultrasonic fatigue cracks always initiated at the surfaces of the files, where the secondary phases or impurities existed and induced fatigue cracks under repeated stress.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 744 ◽  
Author(s):  
Mikel Armentia ◽  
Mikel Abasolo ◽  
Ibai Coria ◽  
Joseba Albizuri

Fatigue is the most common mechanical failure type in dental implants. ISO 14801 standardizes fatigue testing of dental implants, providing the load-life curve which is most useful for comparing the fatigue behavior of different dental implant designs. Based on it, many works were published in the dental implant literature, comparing different materials, component geometries, connection types, surface treatments, etc. These works are useful for clinicians in order to identify the best options available in the market. The present work is intended not for clinicians but for dental implant manufacturers, developing a design tool that combines Finite Element Analysis, fatigue formulation and ISO 14801 experimental tests. For that purpose, 46 experimental tests were performed on BTI INTERNA® IIPSCA4513 implants joined with INPPTU44 abutments by means of INTTUH prosthetic screws under three different tightening torque magnitudes. Then, the load case was reproduced in a FE model from where the nominal stress state in the fatigue critical section was worked out. Finally, Walker criterion was used to represent accurately the effects of mean stress and predict fatigue life of the studied dental implant assembly, which can be extended to most of the products of BTI manufacturer. By means of this tool, dental implant manufacturers will be able to identify the critical design and assembly parameters in terms of fatigue behavior, evaluate their influence in preliminary design stages and consequently design dental implants with significantly better fatigue response which in turn will reduce future clinical incidences.


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