scholarly journals Durability Optimization of Fiber Grating Hydrogen Sensor Based on Residual Stress

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7657
Author(s):  
Wenbo Ma ◽  
Yuyang Li ◽  
Ning Yang ◽  
Li Fan ◽  
Yanli Chen ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optical Fiber ◽  
Film Thickness ◽  
Equivalent Stress ◽  
Hydrogen Sensor ◽  
Fiber Grating ◽  
Durability Test ◽  
Element Analysis ◽  
The Times

In this paper, in order to improve the durability of optical fiber grating hydrogen sensors, an optical fiber grating hydrogen sensor with high precision, stability, and durability is prepared. Based on the simplified two-dimensional model and finite element analysis, the effects of film thickness, coating speed, and coating times on the residual Mises equivalent stress between the sensor film and substrate were studied, and the optimum coating parameters were determined. The finite element analysis results show that the residual equivalent stress between the film and the substrate increases with the increase in the film thickness between 50 and 150 nm. The range of 200–250 nm is relatively stable, and the value is small. The coating speed has almost no effect on the residual equivalent stress. When the thickness of the film is 200 nm, the residual equivalent stress decreases with the increase in coating times, and the equivalent force is the lowest when the film is coated three times. The best coating parameters are the thickness of 200 nm, the speed of 62.5 μm/s, and the times of coating three times. The results of finite element analysis are verified by the hydrogen sensitivity test and durability test.

Optimization design of titanium alloy connecting rod based on structural topology optimization

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bin Zheng ◽  
Yi Cai ◽  
Kelun Tang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Optimization Design ◽  
Equivalent Stress ◽  
Connecting Rod ◽  
Element Analysis ◽  
Content Type ◽  
The Finite Element Analysis ◽  
Maximum Equivalent Stress

Purpose The purpose of this paper is to realize the lightweight of connecting rod and meet the requirements of low energy consumption and vibration. Based on the structural design of the original connecting rod, the finite element analysis was conducted to reduce the weight and increase the natural frequencies, so as to reduce materials consumption and improve the energy efficiency of internal combustion engine. Design/methodology/approach The finite element analysis, structural optimization design and topology optimization of the connecting rod are applied. Efficient hybrid method is deployed: static and modal analysis; and structure re-design of the connecting rod based on topology optimization. Findings After the optimization of the connecting rod, the weight is reduced from 1.7907 to 1.4875 kg, with a reduction of 16.93%. The maximum equivalent stress of the optimized connecting rod is 183.97 MPa and that of the original structure is 217.18 MPa, with the reduction of 15.62%. The first, second and third natural frequencies of the optimized connecting rod are increased by 8.89%, 8.85% and 11.09%, respectively. Through the finite element analysis and based on the lightweight, the maximum equivalent stress is reduced and the low-order natural frequency is increased. Originality/value This paper presents an optimization method on the connecting rod structure. Based on the statics and modal analysis of the connecting rod and combined with the topology optimization, the size of the connecting rod is improved, and the static and dynamic characteristics of the optimized connecting rod are improved.

Three-Dimensional Nonlinear Contact Finite Element Analysis of Mandibular All-on-4 Design

2015 ◽  
Vol 41 (2) ◽  
pp. e12-e18 ◽  
Author(s):  
Mostafa Omran Hussein ◽  
Mahmoud Elsayed Rabie
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equivalent Stress ◽  
Stress And Strain ◽  
Element Analysis ◽  
Implant Position ◽  
Finite Element Software ◽  
Edentulous Mandible ◽  
Nonlinear Contact ◽  
Position And Orientation

The All-on-4 design was used successfully for restoring edentulous mandible. This design avoids anatomic cripples such as inferior alveolar nerve by tilting posterior implants. Moreover, tilting posterior implants of All-on-4 design had a mechanical preference than the conventional design. On the other hand, the anterior implants are parallel at the lateral incisor region. Several researches showed favorable results for tilting posterior implants. However, research did not study the influence of the anterior implant position or orientation on the mechanical aspects of this design. This study analyzes the influence of varying anterior implant position and orientation of the All-on-4 design using nonlinear contact 3D finite-element analysis. Three copied 3-dimensional models of the All-on-4 design were classified according to anterior implant position and orientation. The frictional contact between fixtures and bone was the contact type in this finite element analysis. Finally, von Mises stress and strain at implant and bone levels were recorded and analyzed using finite element software. Stress concentrations were detected mainly around the posterior implant at the loaded side. Values of the maximum equivalent stress and strain were around tilted implants of design III followed by design II, then design I. Changing the position or orientation of the anterior implants in All-on-4 design influences stress-strain distribution of the whole design.

The Finite Element Analysis on the Compression Splicing Position of Strain Clamp in Guy Tower

2014 ◽  
Vol 680 ◽  
pp. 249-253
Author(s):  
Zhang Qi Wang ◽  
Jun Li ◽  
Wen Gang Yang ◽  
Yong Feng Cheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Equivalent Stress ◽  
Element Model ◽  
Element Analysis ◽  
Elastic Plastic ◽  
The Finite Element Analysis

Strain clamp is an important connection device in guy tower. If the quality of the compression splicing position is unsatisfied, strain clamp tends to be damaged which may lead to the final collapse of a guy tower as well as huge economic lost. In this paper, stress distribution on the compressible tube and guy cable is analyzed by FEM, and a large equivalent stress of guy cable is applied to the compression splicing position. During this process, a finite element model of strain clamp is established for guy cables at compression splicing position, problems of elastic-plastic and contracting are studied and the whole compressing process of compressible position is simulated. The guy cable cracks easily at the position of compressible tube’s port, the inner part of the compressible tube has a larger equivalent stress than outside.

Application of Finite Element Analysis for the Prediction of the Fatigue Lifetime of Spot Welds with Triple SPCC plates

2007 ◽  
Vol 345-346 ◽  
pp. 1453-1456
Author(s):  
Byoung Ho Choi ◽  
Dong Ho Joo ◽  
Sam Hong Song
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shell Model ◽  
Crack Opening ◽  
Equivalent Stress ◽  
Shear Loading ◽  
Opening Angle ◽  
Element Analysis ◽  
Fatigue Lifetime ◽  
Empirical Prediction

The fatigue characteristic of triple spot welded SPCC plates with the variation of the thickness and the geometry under tensile-shear loading is studied by finite element analysis (FEA) and the obtained data is compared with experimental data. Using 3-D solid element model and 3-D beam-shell model, the maximum equivalent stress and the beam deformation angle (BDA) for various thickness and geometry is studied. The linear relation between crack opening angle (COA) from experiment and the BDA from FEA for beam-shell model is represented, and the empirical prediction of fatigue lifetime is proposed using the relation between COA and BDA.

Finite Element Analysis of the Influence of Balance Mode on Rolling Mill Universal Spindle Strength

2014 ◽  
Vol 548-549 ◽  
pp. 449-453 ◽  
Author(s):  
Zhi Qiang Guo ◽  
Ze Lu Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Model ◽  
Rolling Mill ◽  
Loading Condition ◽  
Equivalent Stress ◽  
Bending Moment ◽  
Element Model ◽  
Element Analysis ◽  
Universal Spindle

For the problem of balance bearing of universal spindle in rolling mill being prone to damage, the paper established mechanical model and finite element model of universal spindle. The paper has analyzed that the shear and bending moment in the middle of the shaft is the largest. The fillet near shoulder of balance bearing of the spindle is dangerous part. In order to reduce principal stress of universal spindle caused by moment, the paper improved balance mode of the spindle. The equilibrant was applied from in one place of shaft to put in two places. After optimizing, equivalent stress of the spindle is slight smaller than before under the same loading condition, which illustrates that the strength of the spindle is appropriately improved. Although the effect is not obvious, this has played a guiding role for the optimization of balance mode of universal spindle.

Finite Element Analysis of Hydraulic Clipping Machine Shear Platform Dased on ANSYS

2014 ◽  
Vol 945-949 ◽  
pp. 190-193
Author(s):  
Hai Lin Wang ◽  
Yi Hua Sun ◽  
Ming Bo Li ◽  
Gao Lin ◽  
Yun Qi Feng ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Elastic Strain ◽  
Optimization Design ◽  
Equivalent Stress ◽  
Element Model ◽  
Element Analysis ◽  
Maximum Equivalent Stress

Q43Y-85D type crocodile hydraulic clipping machine was taken as research object to optimization design. A finite element model for clipping machine was built using shell unit as fundamental unit. ANSYS12.0 finite element method was used to analyze the deformation and stress distribution of the shear platform model of hydraulic clipping machine. The result showed that the maximum equivalent stress at the dangerous area was 368.162 MPa and the maximum elastic strain was 0.1814×10-2 mm. After the structural optimization design, it was found that the maximum equivalent stress decreased to 186.238 MPa which did not exceed the material’s yield limitation 215 MPa and the maximum elastic strain decreased to 0.919×10-3 mm which satisfied the requirement of stiffness.

Finite Element Analysis of the Rolling-Sliding Contact of Vibrationally Loaded Bearings Based on a Micro Friction Model

2013 ◽  
Vol 768-769 ◽  
pp. 714-722 ◽  
Author(s):  
Andreas Konrad ◽  
Wolfgang Nierlich ◽  
Jürgen Gegner
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Residual Stresses ◽  
Equivalent Stress ◽  
Rolling Contact ◽  
Sliding Contact ◽  
Element Analysis ◽  
Fem Model ◽  
Mixed Friction

Mixed friction acting in a rolling contact increases the v. Mises equivalent stress and shifts the maximum towards the surface. Tangential stresses are superimposed to the stress distribution. The resulting position of the maximum v. Mises stress depends on the magnitude of the friction coefficient and is located directly on the surface from values of about 0.25 upwards. The impact of three-dimensional machine vibrations on rolling bearings in operation can cause severe mixed friction running conditions. Residual stress distributions measured on indentation-free raceways indicate high friction coefficients of up to greater than 0.25. The surfaces reveal smoothing of the finishing structure but no adhesive wear. The simulation of the vibrationally loaded rolling-sliding contact is based on the tribological model of localized friction coefficient. This approach avoids seizing by allowing for increased friction only in intermittently changing subareas of the contact at low sliding speed. The macroscopic friction coefficient, meeting a mixing rule, does not exceed 0.1. The finite element method (FEM) is used for the stress analysis. In the first step, a simplified FEM model involves a circumferentially oriented band of high friction coefficient from 0.2 to 0.5 within a cylindrical roller contact. The resulting depth distributions of the v. Mises equivalent stress during overrolling and the corresponding residual stresses are evaluated below the inner ring raceway of the bearing. The features of the FEM model are discussed in detail. The increased sliding friction in the band shifts the maximum of the v. Mises equivalent stress to the surface. Compressive residual stresses are induced in the edge zone. Depending on the applied Hertzian pressure, an additional subsurface peak occurs. First results of the finite element analysis are presented.

scholarly journals A Study on improving the durability of drone according to the area of impact applied with finite element analysis method

2018 ◽  
Vol 7 (2.12) ◽  
pp. 276
Author(s):  
Kye Kwang Choi ◽  
Jae Ung Cho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Stress ◽  
Equivalent Stress ◽  
Basic Data ◽  
Deformation Analysis ◽  
Analysis Method ◽  
Element Analysis ◽  
Finite Element Analysis Method ◽  
Rear Impact

The objective of this paper is to identify the dangers of damage on drones according to the area of impact and obtain the basic data for improving the durability. The durability by impact according to the weight and speed of the large-size drone is calculated and analyzed using a finite element analysis method with 3D model according to the area of impact. For the analytical results, the possibility of fracture is identified and weak areas are improved through the distribution of equivalent stress and deformation analysis using polyester resin, which is a material used for the drone. The equivalent stresses applied to drones in head-on impact and broadside impact were 296.22MPa and 349.36MPa respectively. The broadside impact producing the highest fracture stress of over 300MPa and the bottom part of the battery pack is limited to a fairly narrow area, so the improvements can be made by reinforcing this area. The great damage may occur from rear impact as the results show 828.28MPa, which is much higher than the fracture stress at rear impact to be the greatest drawback. Also for the deformation results, the values of head-on impact and broadside impact were in the safety range according to the elongation rate, while the drone greatly suffered from deformation and damage in rear impact. At the simulation analysis, the change of material must also be considered along with the change in design for rear collision. It is thought to obtain the basic data for future designing of large-sized drones by referring the results of this research, and it may contribute to the improvement of drone durability. By applying this study result to the drone, it is thought to contribute to the improvement on the durability of drone design due to the area of impact.  

scholarly journals Effect of cartilage thickness mismatch in osteochondral grafting from knee to talus on articular contact pressures: A finite element analysis

2021 ◽  
Vol 32 (2) ◽  
pp. 355-362
Author(s):  
Ömer Faruk Kılıçaslan ◽  
Ali Levent ◽  
Hüseyin Kürşat Çelik ◽  
Mehmet Ali Tokgöz ◽  
Özkan Köse ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Equivalent Stress ◽  
Cartilage Thickness ◽  
Frictional Stress ◽  
Element Analysis ◽  
Grafting From ◽  
Von Mises ◽  
Osteochondral Grafting

Objectives: The aim of this study was to investigate the effect of cartilage thickness mismatch on tibiotalar articular contact pressure in osteochondral grafting from femoral condyles to medial talar dome using a finite element analysis (FEA). Materials and methods: Flush-implanted osteochondral grafting was performed on the talar centromedial aspect of the dome using osteochondral plugs with two different cartilage thicknesses. One of the plugs had an equal cartilage thickness with the recipient talar cartilage and the second plug had a thicker cartilage representing a plug harvested from the knee. The ankle joint was loaded during a single-leg stance phase of gait. Tibiotalar contact pressure, frictional stress, equivalent stress (von Mises values), and deformation were analyzed. Results: In both osteochondral grafting simulations, tibiotalar contact pressure, frictional stress, equivalent stress (von Mises values) on both tibial and talar cartilage surfaces were restored to near-normal values. Conclusion: Cartilage thickness mismatch does not significantly change the tibiotalar contact biomechanics, when the graft is inserted flush with the talar cartilage surface.

Finite element analysis and animal test verification of nitinol alloy iliac vein stent performance

2019 ◽  
Vol 233 (17) ◽  
pp. 6197-6208 ◽  
Author(s):  
HQ Feng ◽  
SB Wang ◽  
YG Wang ◽  
XQ Li ◽  
YJ Mao ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Strength ◽  
Equivalent Stress ◽  
Iliac Vein ◽  
Control Group ◽  
Element Analysis ◽  
Animal Test ◽  
Significant Difference ◽  
Test Verification

The design and fatigue strength of a nitinol iliac vein stent (NIVS) proposed in this study are assessed using the finite element analysis method. The influence of stent diameter and different release scales on its strength, lifespan and biomechanical properties of the vein wall is analyzed for self-developed NIVS of three different diameters (12, 14 and 16mm) and length of 26mm, which were implanted into the corresponding iliac vein with different release scales (80% and 90%). The results obtained strongly indicate that with an increase in the release scale, the equivalent elastic strain, safety factors of fatigue strength, and equivalent stress of the vessel wall exhibit a downward trend, while the most stressed cross-section coincides with the arc of stent-connecting rods. The efficiency and safety of the above stents were verified by in vivo tests (with observation periods of 30, 90 and 180 days after operation) on ten lab pigs, which underwent NIVS implantation into the iliac veins, with observation of hemodynamics, stent deployment, presence/absence of thrombosis, and monitoring of stent lumen loss and its rate. During the animal test verification, the stent release was satisfactory, while the radiography revealed no obvious stent displacement at different time points. In addition, the patency rate of the stent was 100%. Except for the control group, where a small amount of old thrombus was found, other stents exhibited no thrombus; at the same time, there was no significant difference in the lumen loss rate of the stent at each time point. Therefore, the proposed nitinol NIVS samples demonstrated a good performance, accurate positioning, and release, in addition to the reduced risk of lateral iliac vein thrombosis.

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