Effects of Metal Material Stent Design Parameters on Longitudinal Stent Strength

2016 ◽  
Vol 723 ◽  
pp. 299-304 ◽  
Author(s):  
Xiang Shen ◽  
Zhong Min Xie ◽  
Yong Quan Deng ◽  
Song Ji
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blood Vessel ◽  
Design Parameters ◽  
Curvature Radius ◽  
Stent Design ◽  
Rigid Surface ◽  
Stent Deployment ◽  
Metal Material ◽  
Stent Deformation

The longitudinal stent deformation (LSD) was usually caused by the external force in the blood vessel. The effects of metal material stent design parameters on the longitudinal stent strength (LSS) were studied using finite element method (FEA). A longitudinal stent compression model was developed and a rigid surface was used to compress the stent after stent deployment in coronary arteries. Results showed that the connector length, the strut amplitude and the curvature radius at the crown junctions influenced the LSS hardly. However, the number of connector played the most significant role in the LSS, and increasing the number of connectors can substantially improve the LSS, and the LSS of stent with four connectors was nearly three times than that of the stent with two connectors. For the shape of connector, the LSS of the S-stent, M-stent and L-stent were successively increased. With regard to the L-stent, increasing the width of connector can improve the LSS. Reasonably changing stent design parameters can effectively strengthen the LSS. Conclusions obtained from this paper can help surgeons to select appropriate stents and designers to optimize the stent design to reduce the LSD.

Numerical Investigation of the Flexibility of a New Self-Expandable Tapered Stent

2020 ◽  
Vol 36 (4) ◽  
pp. 577-584
Author(s):  
X. Shen ◽  
J. B. Jiang ◽  
H. F. Zhu ◽  
Y. Q. Deng ◽  
S. Ji
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Investigation ◽  
Mechanical Performance ◽  
Peak Stress ◽  
Design Parameters ◽  
Stent Design ◽  
Performance Parameters ◽  
Space Width ◽  
Element Method

ABSTRACTFlexibility is one of the important mechanical performance parameters of stent. The flexibility of tapered stents, especially self-expanding tapered stents, remains unknown. In this study, we developed a new selfexpanding tapered stent for tapered arteries and performed a numerical investigation of stent flexibility by using finite element method. The effect of stent design parameters, including taper and link space width, on stent flexibility was studied. The flexibility of the proposed stent was also compared with that of traditional cylindrical stents. Results show that the tapered stent is more flexible than the traditional cylindrical stent. Furthermore, the flexibility of the tapered stent increases with increasing stent taper and stent link space width. The increase in the stent link space width can contribute to the reduction in the peak stress. Therefore, tapered stents with high link space width will improve the stent flexibility. This work provides useful information for improvement of stent design and clinical selection.

Deformations and Stresses in Face-Hobbed Spiral Bevel Gears

2011 ◽  
Author(s):  
Vilmos V. Simon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Nodal Point ◽  
Design Parameters ◽  
Element Discretization ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Tooth Surfaces ◽  
Spiral Bevel ◽  
Element Method

In this study an attempt is made to predict displacements and stresses in face-hobbed spiral bevel gears by using the finite element method. A displacement type finite element method is applied with curved, 20-node isoparametric elements. A method is developed for the automatic finite element discretization of the pinion and the gear. The full theory of the generation of tooth surfaces of face-hobbed spiral bevel gears is applied to determine the nodal point coordinates on tooth surfaces. The boundary conditions for the pinion and the gear are set automatically as well. A computer program was developed to implement the formulation provided above. By using this program the influence of design parameters and load position on tooth deflections and fillet stresses is investigated. On the basis of the results, obtained by performing a big number of computer runs, by using regression analysis and interpolation functions, equations for the calculation of tooth deflections and fillet stresses are derived.

DESIGN FEATURES OF CARBIDE ASSEMBLY WORKING ELEMENTS OF DEFORMING BROACHES

2021 ◽  
pp. 134-142
Author(s):  
Я.Б. Немировский ◽  
И.В. Шепеленко ◽  
С.Е. Шейкин ◽  
Ю.А. Цеханов ◽  
Ф.Й. Златопольский ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Hard Alloy ◽  
Contact Surface ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Design Features ◽  
Working Element ◽  
External Loads

Разработан алгоритм и проведена оценка прочности сборных твердосплавных элементов со сплошной и дискретной рабочими поверхностями. Получены зависимости, позволяющие установить связь между конструктивными параметрами сборных деформирующих инструментов и их прочностью. Выполнены прочностные расчеты деформирующего инструмента для обработки отверстий значительного диаметра со сплошной и дискретной рабочими поверхностями. Численным моделированием, методом конечных элементов получены распределения эквивалентных напряжений в элементах инструмента и контактных напряжений по поверхности контакта твердосплавная вставка-корпус, что позволило проанализировать прочность инструмента под нагрузкой. Определены конструктивные параметры инструмента и приведены алгоритмы последовательности расчета сборных деформирующих элементов (ДЭ). Разработан алгоритм последовательности расчета сборного ДЭ для дискретного протягивания. Предложенная конструкция сборного рабочего элемента позволяет не только улучшить обрабатываемость изделия резания, но и уменьшить расход остродефицитного твердого сплава по сравнению с твердосплавным ДЭ аналогичных размеров на 6 кг. Полученные результаты можно использовать в инженерных расчетах при проектировании сборного инструмента для дискретного деформирования, а также для оценки прочности сборных инструментов, например, фрез, зенкеров, разверток при уточнении внешних нагрузок We developed an algorithm and assessed the strength of prefabricated carbide elements with solid and discrete working surfaces. We obtained dependencies that make it possible to establish a relationship between the design parameters of prefabricated deforming tools and their strength. We performed strength calculations of the deforming tool for machining holes of significant diameter with solid and discrete working surfaces. We obtained the distributions of equivalent stresses in the elements of the tool and contact stresses over the contact surface of the hard-alloy insert - body by numerical modeling, by the finite element method, which made it possible to analyze the strength of the tool under load. We determined the design parameters of the tool and here we give algorithms for the sequence of calculation of prefabricated deforming elements (DE). We developed an algorithm for the sequence of calculating the prefabricated DE for discrete broaching. The proposed design of the prefabricated working element allows not only to improve the machinability of the cutting product but also to reduce the consumption of an acutely deficient hard alloy in comparison with a hard alloy DE of similar dimensions by 6 kg. The results obtained can be used in engineering calculations when designing a prefabricated tool for discrete deformation, as well as for assessing the strength of prefabricated tools, for example, cutters, countersinks, reamers when specifying external loads

Effects of piston design parameters on skirt-liner dynamic behavior

2016 ◽  
Vol 68 (2) ◽  
pp. 250-258 ◽  
Author(s):  
Ridha Mazouzi ◽  
Ahmed Kellaci ◽  
Abdelkader Karas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Loss ◽  
Design Methodology ◽  
Great Influence ◽  
Structural Deformation ◽  
Design Parameters ◽  
Content Type ◽  
Piston Cylinder ◽  
Oil Film Pressure

Purpose – This paper aims to study the effect of piston skirt design parameters on the dynamic characteristics of a piston–cylinder contact. Design/methodology/pproach – This paper focuses on an analysis of the piston dynamic response. The oil-film pressure and the structural deformation were approximated, respectively, by finite difference method and finite element method. Findings – The results show that the design parameters such as clearance, offset and the axial location of piston pin have a great influence on the dynamics of the piston and hence on the piston slap phenomenon and the frictional power loss. Originality/value – All the results mainly focus on the slap noise of the engine and can be used in the piston–liner development at the development of the engine.

Structural Deformation and Stress Analysis of Aircraft Wing by Finite Element Method

2014 ◽  
Vol 906 ◽  
pp. 318-322 ◽  
Author(s):  
M. Fazlay Rabbey ◽  
Anik Mahmood Rumi ◽  
Farhan Hasan Nuri ◽  
Hafez M. Monerujjaman ◽  
M. Mehedi Hassan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Properties ◽  
Structural Deformation ◽  
Design Parameters ◽  
Design Phase ◽  
Aircraft Wing ◽  
Detail Design ◽  
The Cost ◽  
Element Method

Wing of an aircraft is lift producing component. It makes aircraft airborne by generating lift>weight. The wing must take the full aircraft weight during flying. So, it is very sophisticated task for designing a wing by keeping consideration of every design parameters simultaneously. This paper contains analysis of structural properties of wing by using finite element method. For well-organized design all the variables must be considered from the beginning of the design phase. The design phases for aircraft are: conceptual, preliminary and detail design. Until the preliminary design phase the aircraft structure is not considered. During these phases the material of the wing should be selected in such a way so that it can perform efficiently with less unexpected phenomena (drag) for which responsible properties are displacement, stress etc. Currently the most focusing area for the aero-elastic investigation is to design wing with good aerodynamic shape which will associated with less dragging structural behavior. It helps to reduce SFC (Specific Fuel Consumption) and so the cost. The analysis on that has done through Computational means as well as simulation technique to develop knowledge about the variation of aircraft wing structural properties.

Influence of Acetabular Liner Design on Periprosthetic Pressures during Daily Activities

2014 ◽  
Vol 601 ◽  
pp. 159-162
Author(s):  
Mircea Krepelka ◽  
Mirela Toth-Taşcău
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Pressure ◽  
Design Parameters ◽  
Acetabular Liner ◽  
Hip Prostheses ◽  
Small Influence ◽  
The Difference ◽  
Contact Pressures ◽  
Element Method

In this study, periacetabular pressures produced by different acetabular liner geometries were analyzed using Finite Element Method. The cup models consist of hemispherical metal shells fitted with normal and different chamfered polyethylene liner geometries, with the same degree of femoral head coverage. The aim of this study was to understand the influence of the design parameters of the chamfered liners, which are primarily designed to increase the range of motion (ROM) of the hip joint and reduce the risk of impingement, on the acetabular contact pressures. The cup models were loaded to simulate periacetabular pressures during routine activities. The proposed models have been analyzed considering a cup position of 40olateral abduction and 15oanteversion. The results show that the difference in contact pressure between the normal and chamfer models was not substantial in the given orientation of the cup. Also, the increase of the chamfer angle has a small influence on the maximum contact pressures, although that could be also dependent on the reduction of the polyethylene thickness. Pre-clinical testing of total hip prostheses using Finite Element Method enables the evaluation of contact pressures and stress distribution, and proves to be a valuable tool to analyze the parameters reducing the contact pressure.

Robust Optimization for Tube Bending Process Based on Finite Element Method

2012 ◽  
Vol 531-532 ◽  
pp. 746-750
Author(s):  
Xue Wen Chen ◽  
Ze Hu Liu ◽  
Jing Li Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Robust Design ◽  
Process Parameters ◽  
Design Method ◽  
Design Parameters ◽  
Tube Bending ◽  
Performance Variation ◽  
Bending Process ◽  
Element Method

The main causes of performance variation in tube bending process are variations in the mechanical properties of material, initial tube thickness, coefficient of friction and other forming process parameters. In order to control this performance variation and to optimize the tube bending process parameters, a robust design method is proposed in this paper for the tube bending process, based on the finite element method and the Taguchi method. During the robust design process, the finite element analysis is incorporated to simulate the tube bending process and calculate the objective function value, the orthogonal design method is selected to arrange the simulation experiments and calculate the S/N ratio. Finally, a case study for the tube bending process is implemented. With the objective to control tube crack (reduce the maximum thinning ratio) and its variation, the robust design mathematical model is established. The optimal design parameters are obtained and the maximum thinning ratio has been reduced and its variation has been controlled.

scholarly journals Impact of Geometry Effects on Artery Stent Deployment Characteristics

2019 ◽  
Vol 9 (2) ◽  
pp. 2029-2035
Keyword(s):  
Heart Diseases ◽  
Research Work ◽  
Computational Method ◽  
Design Parameters ◽  
Stent Design ◽  
Elastic Recoil ◽  
Stent Deployment ◽  
Strut Thickness ◽  
Maximum Expansion

Intravascular stenting is the leading treatment procedure for atherosclerotic coronary heart diseases. Among the various procedures, it is simpler and faster with a high initial success rate. Stent design, stent material, and clinical procedure decide the efficacy and life of stents. Strut thickness and crown radius are two essential design parameters that dictate expansion characteristics of stents. This research work discusses computational analysis of a specific stent, to explore the influence of thickness of strut on the deployment characteristics like stress/strain, foreshortening, recoil, and dog boning. The optimum stent design is one which gives maximum expansion with minimum stress distribution, dogboning, and elastic recoil. Five similar stent models with thickness ranges from 65μ to 105µ were modeled and computational method was adopted to simulate the transitory expansion nature of stent/balloon system. The FE results were substantiated with an in-vitro experiment. It was found that strut thickness has a major impact on stent recoil and low impact on foreshortening and dogboning. Foreshortening per unit expansion was almost same for entire models. Strut thickness 70μ to 80μ gives better expansion characteristics for the model under study.

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