Dimensional Finite Element Analysis Research Articles

Exploring Nonlinear Behavior of Gasket Joints in DEF Dosing Units through Finite Element Analysis

Gaskets serve the crucial function of maintaining a durable seal within 2fixed components within a mechanical structure, even when subjected to varying pressures and temperatures during operation. Gasket joint is necessary in many mechanical systems to form a leak free joint. DEF dosing system is one of the examples where gasket joints are used to prevent exhaust gases leaking before going through SCR. Gasket joint requires certain minimum pressure to make leak free joints. If the gasket pressure goes below the pressure of the internal fluid in the assembly, then there are chances of leaking the fluid out. If the gasket pressure is increased by applying high bolt preload, then there may be chances of yielding of the flanges or this may cause damage to bolt/nut threads. So, there must be optimum gasket pressure in the assembly. The gasket pressure gets affected by many parameters. The present paper aims to avoid leak in case of gasket joints. There are number of parameters which affects the performance of the gaskets e.g. bolt preload, bolt tightening sequence, internal pressure, temperature of internal fluid, creep of gasket etc. Different analysis has been carried out to check effect of allthese parameter on the contact pressure at the gaskets joint. Initial gasket pressure was mainly controlled by bolt preload/torque. The effect of bolt torque on the performance of the gasket joint assembly was studied. A dimensional nonlinear finite element analysis was carried out on the gasket joint and sealing performance was correlated with experimental study. Different geometric configurations are studied at different bolt pre-load levels. Effect of bolt torque on gasket pressure as well as other components of the assembly was studied. The best configuration which gives gasket pressure above minimum required to maintain leak proof joint and with no yielding in the assembly has been recommended.

Pullout behaviour of strip plate anchors in clay overlying sand

Plate anchors are being increasingly employed to establish mooring systems for offshore floating facilities owing to their notable efficiency and cost-effectiveness. The majority of prior studies have concentrated on plate anchors, examining the vertical to horizontal orientations, particularly when embedded in single layer clay or sand. However, it is common to encounter multiple layers of soil with varying characteristics in practical engineering, leading to inaccurate estimation of pullout capacity when based solely on the properties of a single soil layer. This paper reports pullout behaviours of strip plate anchors in clay overlying sand by adopting two dimensional finite element analysis. To simulate the hardening and subsequent softening behaviour of medium to dense sand, a modified Mohr-Coulomb model is considered. The current Finite Element (FE) results are in good agreement when compared with both previous FE simulations and physical model test data. Then, the soil flow mechanisms (e.g. the accumulated plastic shear strain, the friction angle) surrounding the anchor during pullout out are revealed. Based on a series of FE results, a calculation framework considering the effect of thickness of clay layer is designed to predict the pullout behaviour of plate anchors in clay overlying sand.

Comparative analysis of stress patterns between mono-cortical and bi-cortical mini-screws: A three dimensional finite element analysis

Comparative analysis of stress patterns between mono-cortical and bi-cortical mini-screws: A three dimensional finite element analysis

Improved Coreless Axial Flux Permanent-Magnet Machine With Nonuniformly Distributed Winding

The windings of coreless axial flux permanent-magnet machine (CAFPM) are exposed to the rotor magnetic field, where each back electromotive force (EMF) harmonic is induced not only by several different spatial field harmonics but also by the winding distribution. In order to reduce the time harmonics of back EMF for CAFPM with non-overlapping winding, one new winding structure with non-uniform distributed coils is proposed in this paper, in which the coils are arranged in a non-uniform way with annular distribution in the stator. Firstly, the relationship between uniform and non-uniform distributed windings is analyzed based on the phasor diagram of each coil EMF, and the analytical expression of back EMF under non-uniform distributed windings is established. Secondly, key performance indexes under different working states, like no-load, are investigated by three dimensional (3-D) finite element analysis (FEA). Finally, comprehensive experiments are carried out to verify related theoretical analysis, which demonstrate that the non-uniform distributed windings can effectively reduce the time harmonics and increase the working efficiency.

Three dimensional finite element analysis of biomechanics of osteotomy ends with three different fixation methods after hallux valgus minimally invasive osteotomy.

Biomechanical study of fixation methods post hallux valgus minimally invasive osteotomy using finite element technology hasn't been reported. This study aimed to compare maximum displacement and stress distribution of osteotomy ends after minimally invasive osteotomy fixed by bandage, Kirschner wire, Herbert screw. Foot CT images of a patient with mild-moderate hallux valgus were collected. Three-dimensional finite element model of hallux valgus was established through CT image. This study simulated bandage, Kirschner wire and Herbert screw fixation, and analyzed maximum displacement and stress distribution of osteotomy ends in plantar flexion position of foot after fixation. Maximum equivalent stress of osteotomy end fixed with bandage, Kirschner wire, Herbert screw was 7.8615, 14.253, 8.3156MPa, respectively. Total displacement of osteotomy end fixed by bandage, Kirschner wire, Herbert screw was 0.26,896, 0.022,779, 0.029,195mm, respectively. Maximum stress of Kirschner wire and Herbert screw near osteotomy end was 154.7 and 46.404MPa, respectively. Fixation strength and stability of Kirschner wire and Herber screw were better than bandage. Kirschner wire had stress concentration phenomenon, with potential fracture risk. Stress of Herbert screw was evenly distributed around osteotomy end, and there was a certain stress concentration, playing an important role in maintaining fracture end stability. Herbert screw showed good fixation strength and stability, and stress distribution was uniform, which can well maintain stability of minimally invasive osteotomy ends. Findings of this study would provide a theoretical basis for selection of fixation methods after clinical minimally invasive osteotomy for hallux valgus.

Three Dimensional Finite Element Analysis of Stresses Induced Around Inclined Implants with Different Framework Materials in Maxillary Complete Arch Prostheses (All on 4)

Three Dimensional Finite Element Analysis of Stresses Induced Around Inclined Implants with Different Framework Materials in Maxillary Complete Arch Prostheses (All on 4)

A three dimensional finite element analysis of apical stress distribution during intrusion of maxillary central incisor with different inclinations in labial and lingual appliance systems

The objective of this study was to evaluate apical stress distribution during intrusion of the maxillary central incisor with different inclinations in the labial and lingual appliance systems using a three-dimensional finite element model.The three-dimensional finite element models of the maxillary central incisor were produced with 25 ° (normoclined), 30 ° (proclined), and 20 °(retroclined) inclinations. Each incisor model was subjected to an intrusive force of 15cN. The stress level at the apex was calculated in terms of maximum principal stresses.The stress distribution at the apex and cervix was lower in the labial compared to the lingual appliance system for the maxillary central incisor models with an inclination of 25° (normoclined) and 30° (proclined). Whereas the maxillary central incisor model with 20° (retroclined) inclination in the lingual appliance system showed the maximum stress in the cervical region.During intrusion, no significant differences in stress patterns were seen at the root apex in normoclined and proclined maxillary central incisor models in either of the appliance systems, except for the retroclined central incisor model which showed maximum stresses in the cervical region.

COMPARISON OF MECHANICAL PROPERTIES OF THE IMPLANT MATERIALS- TITANIUM, ZIRCONIUM AND PEEK USING THREE DIMENSIONAL FINITE ELEMENT ANALYSIS

Background And Objective:Dental implants have been universally accepted as the best option for prosthetic rehabilitation of missing teeth.A material of choice for manufacturing dental implants was for long time commercially pure titanium due to its excellent bio compatibility and mechanical properties. Zirconia seems to be a suitable alternative dental implant material because of its tooth like color and biocompatibility. The most promising novel alternative to titanium is polyetheretherketone (PEEK) which is a partially crystalline poly aromatic linear thermoplastic substance. The objective of this study is to study and compare the mechanical properties of titanium, zirconium and PEEK implant materials using three dimensional finite element analysis. Methodology: A randomly chosen computerized tomography was used to obtain the digital model in the initial phase of the work. Only the part portion corresponding to tooth number 35 will be extracted from this model. Screwed cylindrical implants of length 12 mm and diameter 4mm will be modeled and simulated to be placed in the section of the bone. The different models used were model A - Titanium, model B – Zirconium, and model C - PEEK implant models. All models were identical, except for the properties of the used materials and all were exported to the Ansys Workbench V10 finite elements simulation software. Vertical and oblique (45 degree) loads in relation to the long axis of the tooth with 100 N in magnitude were applied. Stress analysis performed by comparing the Von Mises stress components. Fatigue strength and mode of failure were also assessed for the three implant materials. Results: Maximum stress in the peri-implant bone when titanium implant was placed in 35 region was 281.40 Mpa under axial load of 100N. Maximum stress when zirconia implant was placed is 277.99 MPa and when peek implant was placed which amounts for 286.78Mpa. Titanium sustains more life cycle (832840.00) compared to Zirconium (743070.00) and PEEK has much less life cycle (302460.00). Factor of safety is rated on a scale of 0 -15 and results were Titanium (12.42) and Zirconium (11.16) had almost similar values. Peek (6.15) had low safety factor compared to Titanium and Zirconia. Conclusion:Titanium was superior to other two groups in all the properties considered. These results prove why Titanium is still considered to be the gold standard material of choice for dental implant fabrication.

Comparative Evaluation of Teeth Displacement and Stress Generated with Orthodontic Mini-Implant and Infra-Zygomatic Crestal Implant during Intrusion in the Maxillary Arch − A Three Dimensional Finite Element Analysis

Comparative Evaluation of Teeth Displacement and Stress Generated with Orthodontic Mini-Implant and Infra-Zygomatic Crestal Implant during Intrusion in the Maxillary Arch − A Three Dimensional Finite Element Analysis

Influence of implant design and length on stress distribution in immediately loaded implants in posterior maxilla - A two-dimensional finite element analysis.

The aim of this two dimensional (2D) finite element analysis study was to evaluate the influence of implant design (step and tapered) and length on stress distribution at bone implant interface, when placed in maxillary posterior bone under immediate loading protocol. 2D finite element models were developed to simulate the two types of implant designs, i.e., Tapered and step implants of 3.75-mm - Diameter and 6 and 10 mm lengths, respectively. Maxillary posterior bone quality (D4 bone) was simulated with a very thin cortical bone (0.5 mm) for the placement of implants. The respective material properties were assigned. The implant designs incorporated microthreads at the crestal part and rest of the implant body incorporated Acme threads. Forces of 100 Newtons were applied vertically and in oblique direction (at an angle of 45°) to long axis of the implants. Total deformation (micromovements), stresses and strains were evaluated at the bone implant interface. The results of micromovements, stresses and strains were found to be lower for long implants as compared to short implants. Also, all the values were found to be higher for oblique loads as compared to vertical loads. The von mises stress values were highest for 6 mm step implants and lowest for 10 mm step implants. In the presence of low bone density with optimal bone height, standard diameter long step implants can be used. Incorporation of microthreads at the crestal portion and acme threads for body portion of the implant presents a good option to be used under immediate loading protocol.

Flexural performance of steel-reinforced geopolymer concrete one-way slabs: Experimental and numerical investigations

This paper investigated the out-of-plane flexural performances of ambient-cured steel-reinforced slag and fly ash-based geopolymer concrete one-way slabs, in which the activator was the blend of NaOH and sodium silicate solutions (SiO2/Na2O = 3.1–3.3). Twelve specimens were prepared and tested, which included six OPC concrete specimens. The test parameters were concrete type (i.e., geopolymer and ordinary Portland cement (OPC) concrete), concrete compressive strength (i.e., 30 MPa, 40 MPa, and 50 MPa) and longitudinal tensile reinforcement ratio (i.e., 0.82 % and 1.20 %). The failure modes, crack patterns, load–deflection relationships and load–strain relationships of all specimens were carefully studied and reported. Further, a two dimensional (2D) finite element (FE) analysis was conducted to validate the test results. The results of the study indicated that: (1) the geopolymer concrete specimens presented lesser crack width and crack spacing owing to the improved bond between rebar and geopolymer concrete; (2) the cracking load and initial stiffness of geopolymer concrete specimens were slightly lower than that of OPC concrete counterparts; (3) the current Codes of Practice GB50010-2010 and ACI 318-19 provided reasonable predictions of the cracking load and flexural load capacity of the steel-reinforced geopolymer concrete specimens; (4) the developed FE model provided a good prediction of the flexural performance of the tested slabs, and could be used for further parametric investigation.

Intrusion of mandibular incisors using single mini-implant –A finite element study

A deep bite is a complex orthodontic problem that is a common feature of many malocclusions. Depending on the diagnosis, a deep overbite can be corrected. Mini implants can be used for the true intrusion of anterior teeth. FEA is a computer based numerical simulation technique used to calculate deflection, stress and displacement. To analyze stress distribution pattern and displacement of mandibular incisors when intrusive forces are applied using three dimensional finite element analysis. To compare intrusion of lower anterior teeth when ‘V’ pattern force and straight vertical pattern force are applied. A three dimensional finite element model was constructed to simulate mandibular teeth, periodontal ligament and alveolar bone. The displacement of individual tooth (central and lateral incisors) on three-dimensional planes and the von Mises stress distribution were compared. Intrusive forces when applied to four mandibular anterior teeth remarkable tipping of the labial segment was seen when straight vertical elastics were used as compared to the ‘V’ shaped elastics. Within the limits of this study, predictable intrusion with minimum labial tipping is seen using single implant using V pattern elastics.

Studying the effect of space radiation induced defects in multijunction solar cell using APSYS simulation software and comparison with the experimental data

In this paper, the state-of-the-art triple junction solar cell with three sub cells and two tunnel diodes is modeled using two dimensional (2D) APSYS finite element analysis software tool. The effect of electron radiation at 1 MeV and 10 MeV energies for different fluences are investigated by introducing different trap levels, trap states and trap concentrations in InGaP top and InGaAs middle sub cells. Two different structures are modeled by varying layer thickness of base and emitter of both top and middle sub cells to understand its effect on the electrical parameters and efficiency of the solar cell. The main indicative parameters - trap concentration and carrier lifetime is affected by the radiation resulting in alteration of electrical performance of solar cells. The radiation induced defects cause permanent damage to the solar cell structure and degrades the electrical performance of solar cells until its end of life (EOL). In this work, APSYS software tool is used to model radiation induced traps with different trap concentrations, generated the electrical parameters and compared with the experimental results. The results obtained from simulation are in good agreement with the experimental data. Probable traps, trap concentrations and carrier lifetime for different electron radiation energies and fluences were extracted by simulation, which can prove to be difficult to perform experimentally as only a few methods like deep level trap spectroscopy and deep level optical spectroscopy exist for deep level trap studies. This study can therefore save valuable R&D time and cost..

3D biomechanical intrusion effects of infra zygomatic bone screws and temporary anchorage device on total maxillary dentition in treatment of vertical maxillary excess: A FEM study

Many studies have reported on the application and clinical efficiency of full arch maxillary dentition intrusion mechanics; however, studies about biomechanical effects such as stress, strain, and displacements on the teeth and the surrounding tissues are limited. The objectives of study was to evaluate and compare the stress distribution and displacement of total maxillary dentition under intrusion mechanics using a three-dimensional finite element analysisA three-dimensional finite element model was constructed based on computed tomography scan data, and it served basic model. The geometric model was converted to finite element model using Altair HyperMesh software. Model A with pre-adjusted edgewise appliance (PEA) setup and Model B with occlusal Splint setup was evaluated and compared for von mises stress distribution and displacement of total (full arch) maxillary dentition by using three dimensional finite element analysis; with force delivered from infrazygomatic screws and miniscrew. Force levels for Model A and Model B includes a total of 300grams of intrusive force (each side) on maxillary posterior segment from IZC bone screw and 100grams of intrusive force on anterior segment from miniscrew.In the model A; with PEA setup reinforced with two trans-palatal arches, highest von Mises stress of 0.970 Mpa was produced on second molar roots followed by molar roots and premolars and central and lateral incisors roots. In the Model A, maximum intrusive values was seen on crown tip of central and lateral incisors (8.671µm), and lowest displacement values on second molars (2.230µm). Similar pattern of von Mises stress distribution and displacement was observed in the Model B. Model A and Model B provided an effective en masse vertical control of the full arch maxillary dentition. Higher intrusion displacement values were seen in anterior segment than the posterior segments

Three dimensional finite element analysis for evaluation of stress and strain distribution in endodontically treated maxillary central incisor with two different post and core systems

Aim: To assess stress, and strain dissemination characteristics in root canal treated maxillary central incisors restored with two distinct dowel and core materials. Methodology: Five three-dimensional simulations of the central incisor in the maxilla were created with ANSYS (Canonsburg, PA) version 10. MODEL 1 represented a normal morphologic simulation of the incisor. MODEL 2 depicted the incisor with a pre-fabricated fiber-reinforced dowel with a glass ionomer core. The incisor of MODEL 3 consisted of the same pre-fabricated fiber post and composite core. MODEL 4 and MODEL 5 had pre-fabricated light-transmitting posts with a glass ionomer and a composite core, respectively. Each of these simulations was loaded in horizontal, vertical, and oblique directions with a load of 10N, 100N, and 50N, respectively. The resulting Von Mises stress and strain were determined. Results: Maximum stresses and strains were focused at the apex of the glass fiber reinforced post and were minimal in the middle section of the post, whereas maximum stresses and strains were mainly concentrated in the coronal region and were minimal in the middle portion of light-transmitting post. Conclusion: Pre-fabricated optical-transmitting dowel and composite core enhanced dentin stress and strain dispersion throughout various loading parameters.

How do implant threads and diameters affect the all-on-four success? A 3D finite element analysis study

The effect of different thread designs and diameters on the all-on-four concept is unclear. The aim of the study was to clarify the differences in stress distribution of dental implants with various thread designs and diameters based on the all-on-four concept with three dimensional (3D) finite element analysis (FEA). A 3D model of a totally edentulous mandible was used to perform the FEA. Four different models (M1, M2, M3, and M4) including 3.5 and 4.3 mm diameter dental implants with active and passive threaded designs were generated. The dental implants were positioned according to the all-on-four concept. The Von Mises stresses on dental implants and maximum and minimum principal stresses (Pmax and Pmin) on bony structures were calculated under vertical, oblique and horizontal loads. For Von Mises stresses, the highest stress values were detected on the distal implants for all models. Distal implants had also the highest stress values for vertical loading. The Von Mises stresses were found to be concentrated around the implant's neck. In all models the highest Pmax and Pmin stresses occurred in the bone surrounding the distal implant. It was noted that the active threaded implants showed the highest Pmax and Pmin stress values. The implant thread design and diameter might have a strong influence on the stress values in the all-on-four concept.

Determination of plastic properties of surface modification layer of metallic materials from scratch tests

A new test method was proposed to extract plastic parameters, i.e., yield stress and strain hardening index, and interfacial coefficient of friction of metallic materials via scratch tests with a pyramid indenter based on dimensional analysis and finite element analysis. Yield stress and strain hardening index of scratched materials can be calculated with scratch width, residual scratch depth and normal force obtained from the scratch tests. Interfacial coefficient of friction between the scratched materials and scratch tip can be determined by the ratio of tangential force and normal force. The accuracies of the proposed formulas were verified by comparing the results of uncarburized and carburized 18CrNiMo7-6 alloy steel obtained by conventional methods with those by scratch tests. This work provides a convenient method to determine plastic parameters and interfacial coefficient of friction of metallic materials simultaneously, which is important for the mechanical analysis, design and safety evaluation of mechanical parts.

Frequency-independent dynamic stiffness and damping of laterally loaded single piles

A practical analytical model for the analysis of a pile subjected to lateral dynamic loads is presented. The model is based on the damped oscillator representation of a pile-soil system. The stiffness and damping were obtained by fitting the equation that governs the vibration of a damped oscillator to the dynamic displacements of the pile-soil system obtained by a three-dimensional finite element analysis. Unlike existing models, the model is frequency independent. Thus, the stiffness and damping can be used in the analysis of a soil-pile system in the time domain. The numerically obtained stiffness and damping are presented in dimensionless charts and influence factor Tables and can be used for analyses of massless piles and piles with added mass subjected to different loading conditions such as harmonic, impact, or earthquake loading. Time-domain analyses of piles that have been subjected to impact loading and earthquake motion are presented. Using the analytical model with the numerically obtained frequency-independent stiffness and damping compared well with existing models and with three dimensional finite element analyses results.

Development of a new improved closed-form plastic collapse moment solution for structurally distorted and through-wall axially cracked 90° pipe bends subjected to in-plane closing bending moment

Plastic collapse loads of 90° pipe bends with structural defects subjected to in-plane closing bending are systematically examined in this study using three dimensional nonlinear finite element (FE) analyses. The analyses consider the large strain formulation option with the pipe bend material assumed to be of the elastic perfectly plastic (EPP) type. Pipe bends are analyzed by changing the ovality at the mid-section which is varied from 0% to 20% by 5% per step. The through-wall axial crack (TAC) parameter at the pipe bend's crown is varied from 0 to 1 by 0.2 per step. Moment rotation curves are drawn for all simulated pipe bend models and plastic collapse moment (PCM) loads are determined from the corresponding moment rotation curves using the Twice-Elastic-Slope (TES) methodology as recommended by clause NB-3213.25 in section III of ASME B&PV code. Both ovality and TAC of pipe bends significantly affects their plastic collapse moments (PCM) and this almost doubles when ovality and TAC act together. The observed effect of ovality and TAC on pipe bends having thin walled and short bend radius does not significantly change with increasing wall thickness and bend radius. The present FE analysis is validated using experimental PCM loads of pipe bends available in open literature. The crack closing effect of pipe bends during closing bending is examined. Based on the analysis, an improved structural integrity assessment equation for shape imperfect pipe bends with TAC is developed for in-plane closing bending moment loads.

A novel systematic numerical approach on determination of heat source parameters in welding process

The double-ellipsoidal heat source concept, established by Goldak, has been extensively employed to represent the energy distribution in a broad range of arc welding simulation processes. However, the Goldak's parameters need to be exactly and efficiently defined for accurate arc welding simulation. In this study, a novel procedure was proposed to accurately predict the Goldak's parameters in Gas Tungsten Arc (GTA) Welding simulation. A developed three dimensional (3D) Finite element (FE) analysis was performed to generate thirty sets of normalized input (welding pool characteristics) and outputs (Goldak's parameters). The relevance between Goldak's parameters and welding pool characteristics were established using two regression models and Artificial Neural Network (ANN) computing systems. Linear and quadratic regression models and ANN were compared for evaluation of accuracy of the parameters. Analysis of the results indicated that ANN slightly transcends both regression models, even though the regression models and ANN were able to suitably predict Goldak's parameters for welding simulation. Hence, Goldak's parameters for the welding numerical model were estimated and employed from the ANN model. 3D FE analysis based on thermal-elastic-plastic model using predicted Goldak's parameters were then conducted and validated by the experimental tests in terms of the size of welding pool, temperature distribution and induced residual stress. In the proposed procedure, the data set in training process was obtained using an efficient FE model analysis, which eliminates the cost and time associated with plenty of experimental tests.