scholarly journals Análisis experimental y teórico del ensayo de adherencia capa – sustrato en un acero DIN UC1 tratado termoquímicamente por borurización

2020 ◽  
pp. 7-14
Author(s):  
J. Merced MARTÍNEZ-VÁZQUEZ ◽  
Arnulfo PÉREZ-PÉREZ ◽  
Gabriel RODRÍGUEZ-ORTIZ ◽  
Esperanza BAÑOS-LÓPEZ
Keyword(s):  
Surface Morphology ◽  
Layer Thickness ◽  
Industrial Application ◽  
Thermochemical Treatment ◽  
Boride Layer ◽  
The Other ◽  
Von Mises Stress ◽  
Adherence Test ◽  
The Times ◽  
Von Mises

In this work, the effect of the boronizing thermochemical treatment on the adherence and surface morphology of the boride layer formed in DIN UC1 steel was evaluated. The process was carried out by packing at the temperature of 1273 K, at the times of 4800, 6000, 7200 and 14400 seconds. The HRC adherence test based on the VDI 1398 standard, was simulated in COMSOL 5.0®; analysing the effect of the thickness of the boride layer and the roughness on the Von Mises stress, in addition to the stress on the indentation footprint; in which it was observed that by increasing the thickness of the layer from 22.2 to 37.8 µm the stresses increased, and therefore the adhesion of the layer on the substrate improved, which causes only the formation of microcracks. On the other hand, in the greater layer thickness (60.04 µm) the layer delaminates. Therefore, for an industrial application of DIN UC1 steel treated thermochemically by borurization, layer thicknesses up to 37.8 µm are recommended.

Influence of a Hard Surface Layer on the Limit of Elastic Contact—Part II: Analysis Using a Modified GW Model

2002 ◽  
Vol 124 (4) ◽  
pp. 785-793 ◽  
Author(s):  
Takashi Nogi ◽  
Takahisa Kato
Keyword(s):  
Surface Layer ◽  
Layer Thickness ◽  
Contact Area ◽  
Substrate Material ◽  
Von Mises Stress ◽  
Real Contact Area ◽  
Surface Model ◽  
Real Surface ◽  
Correction Factors ◽  
Von Mises

The Greenwood and Williamson microcontact model of rough surfaces is modified to include the presence of a surface layer which is stiffer and harder than the substrate. The axisymmetric contact between a rigid spherical asperity and an elastic layered halfspace is analyzed numerically and correction factors for the contact area, load and the maximum von Mises stress are approximated to a closed form by using curve fits of the numerical results. The correction factors for the contact area and load are applied to the GW model to reflect the effect of the finite layer thickness and the substrate material. The correction factor for the maximum von Mises stress is used to calculate the plasticity index for layered surfaces. Parametric calculation of the ratio of plastic contact area to real contact area is carried out for a TiN-coated steel surface. The modified GW model is compared with a more rigorous real surface model and the validity of the present model is discussed. When the layer thickness is sufficiently large, the influence of the soft substrate can be neglected. A simple criterion for realizing the contact free of the effect of the substrate is proposed.

Stress Distribution Around Two Dental Implant Materials with New Designs: Comparative Finite Element Analysis Study

2021 ◽  
Vol 4 (1) ◽  
pp. 19
Author(s):  
Faaiz Alhamdani ◽  
Khawla H. Rasheed ◽  
Amjed Mahdi
Keyword(s):  
Stress Distribution ◽  
Dental Implant ◽  
Cancellous Bone ◽  
Stress Level ◽  
The Other ◽  
Von Mises Stress ◽  
Uniform Stress ◽  
Element Analysis ◽  
Other Hand ◽  
Von Mises

Background: The introduction of modified thread designs is one of the research areas of interest in the dental implantology field. Two suggested Buttress and Reverse Buttress thread designs in TiG5 and TiG4 models are tested against a standard TiG5 Fin Thread design (IBS®). Purpose: The study aims to compare stress distribution around the suggested designs and Fin Thread design. Methods: Three dental implant models: Fin Thread design, and newly suggested Buttress and Reverse Buttress designs of both TiG5 and TiG4 models were tested using FEA for stress distribution using static (70N, 0°) and (400N, 30°) occlusal loads. Results: The main difference between the suggested Buttress design and Fin Thread design lies in the overload (400N, 30°) condition. Maximum Von Mises stress is less in Buttress design than Fin Thread design. On the other hand the level of Von Mises stress over the buccolingual slop of the cancellous bone in Fin Thread design liess within the lowest stress level. The suggested Reverse Buttress design, on the other hand showed almost uniform stress distribution in both TiG4 and TiG4 models with maximum Von Mises stress higher than the elastic modulus of cancellous bone in overload (400N, 30°) condition. Conclusion: The suggested TiG4 Buttress design might have a minor advantage of stress level in cases of stress overload. In contrast, Fin Thread design shows minimal stress over the buccolingual slop of the cancellous bone. The suggested Reverse Buttress design might be more suitable for the D1 bone quality region with the advantage of almost uniform stress distribution

Optimization of a Bend-Twist-and-Sweep Compliant Mechanism

2014 ◽  
Author(s):  
Joseph Calogero ◽  
Mary Frecker ◽  
Aimy Wissa ◽  
James E. Hubbard
Keyword(s):  
Compliant Mechanism ◽  
Twist Angle ◽  
High Stress ◽  
Peak Stress ◽  
The Other ◽  
Optimal Designs ◽  
Von Mises Stress ◽  
Loading Conditions ◽  
Objective Functions ◽  
Von Mises

The overall goal of this research is to develop design optimization methodologies for compliant mechanisms that will provide passive shape change. Our previous work has focused on designing two separate contact-aided compliant elements (CCE): one for bend-and-sweep deflections, called the bend-and-sweep compliant element (BSCE), and another for twist deflection, called the twist compliant element (TCE). In the current paper, all three degrees of freedom, namely bending, twist, and sweep, are achieved simultaneously using a single passive contact-aided compliant mechanism. A new objective function for a contact-aided compliant mechanism is introduced and the results of the optimization procedure are presented. A bend-twist-and-sweep compliant element (BTSCE) can be inserted into the leading edge spar of an ornithopter, which is an avian-scale flapping wing un-manned air vehicle. The multiple objective functions of the optimization problem presented in this paper are: for upstroke, maximize tip bending and sweep deflections, maximize twist angle, and minimize the mass and peak von Mises stress in the BTSCE, and for downstroke, minimize tip bending and sweep deflections, minimize twist angle, and minimize the mass and peak von Mises stress in the BTSCE. This allows a designer to select a CCE from a set of optimal designs to accomplish all three displacement goals. The BTSCE was modeled using a commercial finite element program and optimized using NSGA-II, a genetic algorithm. The results for a single angled compliant joint (ACJ) for quasi-static upstroke loading conditions are presented. Two optimal designs are discussed and compared, one with a moderate peak stress and moderate deflections, the other with a high peak stress and large deflections. The optimization results are then compared to the previous results for the two independent CCEs. A design study showed that the angle of the ACJ needs to be obtuse to achieve a positive twist angle during upstroke, and an acute contact angle reduces peak stress. The deflection objective functions were relatively insensitive to eccentricity for upstroke and downstroke compared to the other parameters, and a high stress penalty was paid for any gains in deflection. The downstroke objective functions were relatively insensitive to all parameters compared to the upstroke objective functions, and were much smaller in magnitude. The optimization showed that under simplified upstroke loading conditions, the BTSCE with a single ACJ allowed bending deflection near 30% of the length of the BTSCE, twist angle near 0.14 radians, and sweep deflection near 5% of the length of the BTSCE.

Comparison of Torque Transmitting Shaft Connectivity Using a Trilobe Polygon Connection and an Involute Spline

2000 ◽  
Vol 122 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Zella L. Kahn-Jetter ◽  
Eugene Hundertmark ◽  
Suzanne Wright
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
The Other ◽  
Von Mises Stress ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Principal Compressive Stress ◽  
Torque Transmission ◽  
Von Mises ◽  
Involute Spline

The results of a finite element analysis of a trilobe polygon shaft connection used as an alternative for a spline for torque transmission is presented. These results are compared to the results of a finite element analysis previously performed on an involute spline. It is shown that the tensile stress in the polygon shaft is significantly smaller than in the involute spline and is smaller than all the other stresses in both the shaft and the hub in the polygon connection. Furthermore, the magnitudes and distributions of the maximum principal compressive stress, the shear stress, and the Von Mises stress are nearly the same on the shaft and the hub. It appears that polygonal connections can be more advantageous than splined connections because of lower stresses and the lack of stress concentrations typical of splines. [S1050-0472(00)00601-2]

scholarly journals Design and Shape Optimization of a Biodegradable Polymeric Stent for Curved Arteries Using FEM

2021 ◽  
Vol 7 ◽  
Author(s):  
Yasaman Baradaran ◽  
Mostafa Baghani ◽  
Morteza Kazempour ◽  
Seyed Kianoosh Hosseini ◽  
Morad Karimpour ◽  
...  
Keyword(s):  
Optimization Procedure ◽  
Optimization Method ◽  
Mechanical Tests ◽  
Middle Part ◽  
Pareto Set ◽  
The Other ◽  
Von Mises Stress ◽  
Middle Point ◽  
Radial Strength ◽  
Von Mises

Stent treatment has revealed safe and efficient outcomes for straight arteries, while it is still challenging for curved coronary arteries. On the one hand, a stent should be flexible enough to take the artery’s curvature with the least stress to the artery wall. On the other hand, it has to be strong enough to prevent any artery diameter reduction after the implant. In this work, the genetic algorithm multi-objective optimization method is exploited to provide a Pareto set and to design a curvature stent. The design has been performed based on the appropriate flexibility and radial strength design, depending on the characteristics of a particular case study. In the optimization procedure, flexibility and radial strength have been evaluated based on ASTM standard mechanical tests. These tests have been parametrically simulated using the finite element method. The strut curvature is formed by the spline curvature, whose middle point coordinates are two of the optimization variables. The other optimization variable is the thickness of the stent. Based on the Pareto set achieved from the optimization, five different stent designs have been proposed. In these designs, the middle part of the stent is stiffer (in the plaque aggregated) and benefits more radial strength rather than flexibility. At the stent’s extremes, where more deformation takes place, flexibility is weighted more than radial strength. These five design sets differ in their objective weight ratios. At the end of this research, their implementation in a curved vessel is simulated in ABAQUS/CAE, and von Mises stress distribution, maximum von Mises stress, and stent recoil after imposing the stent have been analyzed. The obtained Pareto front can also be a useful guide for physicians to design and manufacture customized stents for each patient.

Effect of Dielectric Materials on Stress-Induced Damage Modes in Damascene Cu Lines

2003 ◽  
Vol 795 ◽  
Author(s):  
Jong-Min Paik ◽  
Hyun Park ◽  
Ki-Chul Park ◽  
Young-Chang Joo
Keyword(s):  
Mechanical Properties ◽  
Hydrostatic Stress ◽  
Three Dimensional ◽  
Dielectric Materials ◽  
The Other ◽  
Von Mises Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Von Mises ◽  
Low K

ABSTRACTVarious low-k materials are being pursued as dielectric materials for future interconnects. However, poor thermo-mechanical properties of low-k materials cause tremendous reliability concerns, thus the proper materials for integration with Cu are not suggested yet. In this study, the line width and spacing dependence of damascene Cu lines embedded by TEOS and low-k materials (CORAL) was analyzed using x-ray diffraction. Generally, the hydrostatic stress of Cu/TEOS was greater than that of Cu/CORAL, while the opposite for von-Mises stress. Using a three-dimensional finite analysis (FEA), the effect of low-k materials on the stress and its distribution in via-line structures of dual damascene Cu interconnects was studied. In the case of Cu/TEOS, the hydrostatic stress was concentrated at the via and on the top of the lines, where it was suspected that the void would nucleate. On the other hand, in the via-line structures integrated with organic low-k materials, large von-Mises stress was maintained in the via. Therefore, the deformation of via, rather than voiding, may be the main failure mode in the interconnects with low-k materials.

scholarly journals PERANCANGAN DAN ANALISIS CARBODY LOKOMOTIF DENGAN METODE ELEMEN HINGGA

KOMPUTEK ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 8
Author(s):  
Arief Herman Soesilo ◽  
Fadelan Fadelan ◽  
Wawan Trisnadi Putra
Keyword(s):  
Yield Stress ◽  
The Other ◽  
Von Mises Stress ◽  
Ansys Software ◽  
Critical Part ◽  
A Value ◽  
Stress Maximum ◽  
Depth Analysis ◽  
Von Mises ◽  
Operational Time

A locomotive is one of critical part in train set, because a locomotive had to bear a big load and has operational time which long enough. So in a locomotive design required more in depth analysis compared to the other means of transportation. The purpose of this research is to make a design locomotive carbody according to those standards applied and analyze stress happened to carbody locomotive designed. In the design of this to analyze carbody locomotive construction strength, the analysis are done using finite element methode(FEM) with help of Ansys software. The simulation of loads working on the structure was made approaching the real loading. Structure of locomotive carbody should be able to hold the loads working on carbody construction. From the design results locomotive carbody that have been made, this locomotive carbody sized length 19000 mm, width 2790 mm, and high 3700 mm. Materials that used for the locomotive carbody design isSS 400 and SM 490A with Yield stress of 245 MPa dan 325 MPa. The analysis results received a value of von mises stress maximum of 195,429 MPa that occurs at the part of the end of underframe (end center sill), where the sress value are still below of Yield stress materials which are in the form of SM 490 at 325 MPa. From the analysis result suggests that overall locomotive carbody structure can be expressed as safe and able to hold the loads operational.

scholarly journals Optimization of Tungsten Carbide Opposite Anvils Used in the In Situ High-Pressure Loading Apparatus

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Zhang Ying ◽  
Chen Xiping ◽  
Sun Guangai ◽  
Lu Yuping ◽  
Gong Jian ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Tungsten Carbide ◽  
The Other ◽  
Von Mises Stress ◽  
Pressure Loading ◽  
Support Ring ◽  
Maximum Value ◽  
Von Mises ◽  
Good Agreement

In order to optimize the structure of anvils, finite element method is used to simulate two kinds of structures, one of which has a support ring but the other one does not. According to the simulated results, it is found that the maximum value of pressure appears at the center of culet when the bevelled angle is about 20°. Comparing the results of these two kinds of structures, we find that the efficiency of pressure transformation for the structure without support ring is larger than that for the structure with support ring. Considering the effect of von Mises stress, two kinds of tungsten carbide opposite anvils have been manufactured with bevelled angle of 10°. The experimental results for these two anvils are in good agreement with the simulation.

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

The Influence of Loading Position in A Priori High Stress Detection using Mode Superposition

2020 ◽  
Vol 1 (1) ◽  
pp. 93-102
Author(s):  
Carsten Strzalka ◽  
◽  
Manfred Zehn ◽  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
A Priori ◽  
High Stress ◽  
Von Mises Stress ◽  
Detailed Knowledge ◽  
Variable Loading ◽  
Numerical Effort ◽  
Von Mises

For the analysis of structural components, the finite element method (FEM) has become the most widely applied tool for numerical stress- and subsequent durability analyses. In industrial application advanced FE-models result in high numbers of degrees of freedom, making dynamic analyses time-consuming and expensive. As detailed finite element models are necessary for accurate stress results, the resulting data and connected numerical effort from dynamic stress analysis can be high. For the reduction of that effort, sophisticated methods have been developed to limit numerical calculations and processing of data to only small fractions of the global model. Therefore, detailed knowledge of the position of a component’s highly stressed areas is of great advantage for any present or subsequent analysis steps. In this paper an efficient method for the a priori detection of highly stressed areas of force-excited components is presented, based on modal stress superposition. As the component’s dynamic response and corresponding stress is always a function of its excitation, special attention is paid to the influence of the loading position. Based on the frequency domain solution of the modally decoupled equations of motion, a coefficient for a priori weighted superposition of modal von Mises stress fields is developed and validated on a simply supported cantilever beam structure with variable loading positions. The proposed approach is then applied to a simplified industrial model of a twist beam rear axle.

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