Dimensional Finite Element Research Articles

The simulation analysis of sealing performance of cone-cone premium tubing connection under combined loads

Under the complex downhole loads, premium tubing connections often suffer from seal failure and threaded connection failure, leading to tubing string leakage and even safety accidents. Therefore, this paper focuses on the cone-cone premium tubing connection, simulating the make-up process and downhole load conditions, establishing three dimensional finite element models of premium tubing connections, analyzing the distribution of equivalent stress and contact pressure on sealing surface, shoulder and thread. The results show that the stress is mainly concentrated on the shoulder and sealing surface under the make-up torque. The equivalent stress on the shoulder shows a trend of increasing first and then stabilizing. The equivalent stress at the sealing surface tends to be stable first and then decreases. Under the combined loads, the overall equivalent stress of connection increases. The contact pressure decreases slightly in the area of sealing surface and the shoulder inflection point. It may cause joint failure and leakage, when the internal pressure is over 80MPa and the axial compressive load is greater than 800kN, which will lead to the maximum equivalent stress of the threaded part exceed 5.5% of the yield strength.

Effect of Ferromagnetic Core Material Types on Solenoid Actuator Performances

In order to introduce the effects of magnetic field characteristics (B-H) relationship in magnetic field problems analysis, nonlinear method of analysis by using some sort of numerical technique need to complete the analysis. In this work, three dimension finite element analysis is used for solenoid actuator studying. Two types of ferromagnetic, Ferro cobalt and silicon iron used where B-H curves for both materials are introduced in the iterative numerical solution. The results appears the increasing of armature force when the relative permittivity of the material exhibit large value depending on the characteristic of the material used in the solution.

Numerical investigation of pullout capacity for inclined strip plate anchors in sand

Plate anchors have been widely regarded as one of the most efficiency solutions for offshore structures in deep sea. Most of previous studies focus on the vertical or horizontal plate anchors embedded in sand. However, after the caisson foundation is withdrawn, the vertical plate anchor rotates to a certain angle from the horizontal plane in the process of resisting tension, which makes the analysis of pullout capacity of inclined plate anchors in sand relatively complex. This study, by using two dimensional finite element (2D-FE) method, takes a deep insight on the behaviour of strip plate anchors with different inclinations in loose to dense sand. A modified soil model is adopted to explore the hardening and softening behaviour of medium dense and dense sand. The FE results show a good agreement with previous numerical results and centrifuge test data. A series of FE cases are conducted to explore the effect of embedment ratios, plate inclinations and sand relative densities on the pullout capacity of inclined strip plate anchors. A new equation is proposed to estimate the ultimate pullout capacity of strip plate anchors with different inclinations in different relative densities of sand, which serves as a guidance for engineering design of inclined strip plate anchors in sand.

A new structure for line-start non-slotted axial-flux permanent magnet motor, proposing a novel 3D FEA-based demagnetization reduction approach

PurposeThis paper aims to propose a novel simple and efficient structure for line-start axial-flux permanent magnet (LSAFPM) synchronous motor, especially regarding the permanent magnets (PMs) demagnetization reduction.Design/methodology/approachAt first, a primitive raw scheme of the new structure for the LSAFPM motor is introduced. Considering this raw scheme, the levels of irreversible demagnetization in various regions throughout the entire volume of each PM are evaluated using 3 dimensional (3D) finite elements analysis (3D FEA) in full loading condition during startup until reaching steady state. Based on the results of these analyses, the primitive structural scheme is then modified through segmenting (cutting into four pieces) each PM from where the worst irreversible demagnetization levels occurred.FindingsAs will be demonstrated by the results of 3D FEA, the proposed modified structure is not only capable of successful startup and synchronization of the motor but also it considerably reduces the PM demagnetization level. Thus, the performance of the motor is significantly improved.Originality/valueThe demagnetization of PMs is an important effect in PM synchronous motors, which can greatly affect motor performance. Therefore, it is necessary to be considered in the motor design processes. This effect becomes much more significant in the line-start PM motors because the usual high-magnitude startup induction current produces a strong armature-reaction magnetic field, which may cause the PMs to be irreversibly demagnetized. The approach proposed in this paper provides a structural solution to mitigate the PM demagnetization effect and thereby improve the performance of an LSAFPM motor through modifying the structure of the LSAFPM motor according to an FEA-based PM demagnetization analysis. As a considerable contribution, in this analysis, the variation of demagnetization level between different areas inside each PM is computed and is considered as a basis for proposing an appropriate structural modification to mitigate the PM demagnetization effect as much as possible.

Parametric analysis on the flexural behaviour of RC beams strengthened with prestressed FRP laminates

In this paper, the effectiveness of reinforced concrete (RC) beams strengthened with prestressed basalt fibre-reinforced polymer (BFRP) laminates was parametrically studied through discrete displacement-coordinated finite element (FE) method. Three dimensional (3D) FE models were established based on experiments, and the reliability of the FE model was verified. The influences of material properties, prestress load level, reinforcement ratio, and shear span on the overall behavior were investigated. The results demonstrated that the optimal capacity of strengthened beam can be achieved in large shear span with low reinforcement ratio and high-strength concrete. The cracking load of RC beams was also significantly increased by strengthening with prestressed BFRP laminates. Then, polynomial equations were fitted to quantify the influences of different parameters on capacity enhancement. The shear span ratio was found to be the most important factor. In addition, the utilisation efficiency of BFRP is much higher than that of carbon FRP (CFRP) with the same section and prestress level due to the strong deformation ability.

Dental biomechanics of root-analog implants in different bone types

Statement of problemWhen implants are applied to restore oral function, the masticatory load on the crown will lead to stress development in all parts of the crown-abutment-implant-bone system. An optimal design of the whole system will be important for sustained function. PurposeThe purpose of this 3-dimensional (3D) finite element analysis (FEA) study was to evaluate the influence of the root-analog implant (RAI) design in molar rehabilitation and bone type. Material and methodsTwelve 3D models of single posterior implant-supported restorations were created according to the zirconia implant design (monotype, 2-piece, or RAI) and bone type (D1, D2, D3, and D4, according to the Misch classification). The models were composed of cortical bone, cancellous bone, implant, cement layers, and a monolithic ceramic crown. For the 2-piece zirconia implant model, the titanium base, prosthetic screw, and framework were also designed. All materials were assumed to behave elastically throughout the entire analysis. The bone was fixed, and an axial loading of 600 N was applied to the contacts on the occlusal surface of the crowns. Results for the crown and implant were obtained in maximum principal stress, as well as the von Mises stress for the model and bone microstrain. ResultsHigh stress concentration was observed at the intaglio surface of the crowns near the loading region. Regardless of the design, the stress trend in the implant was similar, increasing proportionally to the bone type (D1>D2>D3>D4). RAI showed a homogeneous stress field near the values calculated for the conventional designs, but with lower magnitudes. The 2-piece zirconia model showed the highest stress magnitude regardless of the bone type and, therefore, the highest failure risk. All models showed a higher strain in the cortical bone than in the cancellous bone, located predominantly in the cervical region. A strain analysis showed that both conventional implant models presented similar behavior for D1 and D2 bone types, with an increasing difference for D3 and D4. RAI showed the lowest strain regardless of the bone type. ConclusionsRoot-analog zirconia implants present a promising biomechanical behavior for dissipating the masticatory load in comparison with conventional screw-shaped implants.

3-Dimensional heat transfer modeling for laser powder bed fusion additive manufacturing using parallel computing and adaptive mesh

In this article, an innovative 3-dimensional (3D) heat-transfer finite element parallel-computing model with adaptive mesh capability, named LPBFSim, for Laser Powder Bed Fusion (LPBF) additive manufacturing is introduced for high precision prediction of melt pool dimensions and single-layer part-level process simulations. Numerical modeling can significantly reduce the expense of the sole deployment of trial-and-error experiments for achieving optimal process parameters. The previously developed single-track model [1] is highly accurate to predict melt pool dimensions for different combinations of process parameters. However, without using parallel computing and an adaptive mesh, it is very challenging to scale it up to a multi-track model or even a part-level model due to the high computational cost. The proposed model is parallelized to be able to run on a cluster and aimed to solve this difficulty while keeping all the accuracy from the previous version. Single-track, multi-track, and single-layer part-level models have been implemented to demonstrate its efficiency and accuracy.

Three dimensional high order finite volume element schemes for elliptic equations

AbstractIn this work, we construct and analyze three dimensional high order finite volume element schemes for elliptic equations. In these schemes, the trial function space is chosen as the standard rth order Lagrange finite element space, where is an arbitrary positive integer; the test function space is chosen as the piecewise constant space with respect to the dual mesh of which the control volumes are constructed using Gauss points in each element of the primal mesh. We investigate the inf–sup property of these schemes and based on it, we prove that , and , where is the exact solution, is the rth order finite volume element solution and is the piecewise rth order Lagrange interpolation of . Several numerical examples are presented to verify the theoretical findings.

Finite Element Study of Stress Distribution with Tooth-Supported Mandibular Overdenture Retained by Ball Attachments or Resilient Telescopic Crowns.

The removable partial denture must keep health of the remaining teeth and the supporting tissues through the distribution of chewing forces on the abutment teeth and alveolar process.This study aimed to evaluate stress distribution with canines-supported mandibular overdenture retained by two different attachment types: ball attachments or resilient telescopic crowns. Two 3-dimensional finite element models consisting of the cortical mandible bone, cancellous mandible bone, oral mucosa, canines, periodontal ligaments, the two attachment types, and overdenture were simulated. The models were imported into the mathematical analysis software Ansys Workbench V 15.0. All materials were considered to be homogeneous, isotropic, and linearly elastic. A vertical bilateral load of 120 N was applied to the central fossa of the first molars. The von Mises stress was calculated for canines, cortical, and cancellous bone. The maximum von Mises stress of the ball attachments model was 35.61, 4.28, 7.82, and 1.29 MPa for canines, cortical alveolar bone of canines, cortical alveolar bone at the distal end of the overdenture, and cancellous alveolar bone of canines, respectively. The maximum von Mises stress of the resilient telescopic crowns model was 39.22, 4.74, 7.06, and 1.05 MPa for canines, cortical alveolar bone of canines, cortical alveolar bone at the distal end of the overdenture, and cancellous alveolar bone of canines, respectively. Resilient telescopic crowns distribute the stresses between canines, alveolar bone of canines, and overdenture supporting alveolar bone. Ball attachments transfer less stress to the canines and cortical alveolar bone of the canines, but more stress to the cancellous alveolar bone of canines and alveolar bone at distal end of the overdenture. Resilient telescopic crowns are preferred over ball attachment when the abutment teeth have good periodontal support.

Influence of soil–structure interaction on seismic demands of historic masonry structure of Kashan Grand Bazaar

Heritage structures are an important part of the history of each community as well as an economic resource. This study aims to investigate the earthquake damage and failure mechanism of a historic Bazaar located in Kashan (center of Iran), which dates back to the eighteenth century. Numerical models were built by a macro method, considering two cases of fixed support and soil–structure interaction (SSI). To assess the structural behavior, modal, nonlinear static, and dynamic time history analyses were performed using a three dimensional finite element method. The results of SSI analysis show an intense weakness of the structure against the required demand based on the design spectrum. Also, foundation flexibility has a great impact on the vibration characteristics, displacement demand, and damage distribution. By comparing the results of time history analysis to the pushover procedure, a lower shear value and higher displacement are obtained. Furthermore, the damage process is as dome collapse alongside short arch, consequently long arch collapse followed by pier wall overturning.

Evaluation of Stress in Upper Jaw Caused By Orthodontic Mini-Screws (Oms) Produced From Different Biomaterials Using 3 Dimensional Finite Element Analyse

Evaluation of Stress in Upper Jaw Caused By Orthodontic Mini-Screws (Oms) Produced From Different Biomaterials Using 3 Dimensional Finite Element Analyse

The effects of different types of periodontal ligament material models on stresses computed using finite element models

Finite element (FE) method has been used to calculate stress in the periodontal ligament (PDL), which is crucial in orthodontic tooth movement. The stress depends on the PDL material property, which varies significantly in previous studies. This study aimed to determine the effects of different PDL properties on stress in PDL using FE analysis. A 3-dimensional FE model was created consisting of a maxillary canine, its surrounding PDL, and alveolar bone obtained from cone-beam computed tomography scans. One Newton of intrusion force was applied vertically to the crown. Then, the hydrostatic stress and the von Mises stress in the PDL were computed using different PDL material properties, including linear elastic, viscoelastic, hyperelastic, and fiber matrix. Young's modulus (E), used previously from 0.01 to 1000 MPa, and 3 Poisson's ratios, 0.28, 0.45, and 0.49, were simulated for the linear elastic model. The FE analyses showed consistent patterns of stress distribution. The high stresses are mostly concentrated at the apical area, except for the linear elastic models with high E (E>15 MPa). However, the magnitude varied significantly from -14.77 to -127.58 kPa among the analyzed patients. The E-stress relationship was not linear. The Poisson's ratio did not affect the stress distribution but significantly influenced the stress value. The hydrostatic stress varied from -14.61 to -95.48 kPa. Different PDL material properties in the FE modeling of dentition do not alter the stress distributions. However, the magnitudes of the stress significantly differ among the patients with the tested material properties.

Effet des tunnels de vis sur la résistance du fémur proximal après le retrait du matériel : analyse par éléments finis

BackgroundThe presence of screw tunnels in the femoral neck is a problem for patients with proximal femoral fractures after removal of internal fixation. The question of how much does the existence of the screw tunnels affect the strength of the femur and whether the patient needs to be protected with an adjunctive device has been controversial. The objective of this finite element analysis was to determine (1) whether the screw tunnels affects normal weight bearing after removal of internal fixation of a proximal femur fracture, (2) which screw tunnels parameters affect the weight bearing capacity of the entire femur. HypothesisThe presence of the screw tunnels reduces the load-bearing capacity of the femur and the arrangement, diameter and wall thickness of the screw tunnels affect the load-bearing capacity of the femur. Materials and methodsTwenty patients who underwent surgical treatment for proximal femur fracture at our hospital were included in the study. Computed tomography (CT) values of the screw tunnel wall in the femur after removal of internal fixations were analyzed. Mimics v16.0 and Hypermesh v13.0 software programs were used to generate 3-dimensional (3D) tetrahedral finite element models of the proximal femur with different screw tunnel numbers, diameters, thicknesses and arrangements. An acetabulum exerting a vertical pressure load of 600N on the femoral head was simulated and the force on various parts of the femur in each model was calculated. ResultsThere was no difference in the Hounsfield Units of the tunnel walls and cortical bone of the proximal femur (893.48±61.28 vs. 926.34±58.43; p=0.091). In each of the 3D models, the cancellous bone was the first structure to reach maximal stress. The compressive strength of the femur decreased with increasing thickness of the screw tunnel wall and decreased with increasing tunnel diameter. The femoral neck model with the inverted triangle screw tunnel arrangement had the highest compressive strength. DiscussionThe femoral neck with screw tunnels can withstand day-to-day stress without special intervention. For femoral neck fractures fixed with cannulated screws, inverted triangle screws are recommended; For a single screw tunnel in the femoral neck, the larger the diameter of the femoral neck internal screw channel, the weaker the load-bearing capacity of the femur. Level of evidenceIII; well-designed computational non-experimental study.

Numerical Analysis on the Bending Capacity of the Concrete-Filled Micro-Steel-Tube Piles

The finite element analysis model is developed to investigate the bending capacity of the concrete-filled micro-steel-tube (CFMST) piles. First, the classical elastic-plastic model is employed to describe the constitutive relation of the steel material, while the plastic damage model is applied to portray the concrete material. Then, the three dimensional (3D) finite element numerical model for analyzing the flexural bearing capacity of the CFMST pile is established by virtue of the ABAQUS software. The reliability and accuracy of the present numerical model is carefully validated by comparing with the experimental data. The influence of the concrete strength grade, wall thickness of the steel tube, external diameter of the steel tube, and yield strength of the steel are analyzed in detail. It is shown that increasing the wall thickness/external diameter of the steel tube and the yield strength of the steel can greatly improve the flexural bearing capacity of the CFMST pile. Finally, a concise formula for the ultimate bending moment of the CFMST pile is proposed, which could be directly applied into the future engineering design.

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

The effects of erupting mandibular 3 molar on the dental arch: A FEM study

Role ofErupting Mandibular 3 molars as a cause of incisor crowding in the lower arch continues to be controversial. The relation between 3 molar and dental crowding has not been established. To determine the area of stress distribution and tooth displacement during eruption of mandibular 3 molar in mesioangular and horizontal impaction. Three dimensional finite element models were generated based on computed tomography scan data. From computed tomographic scans of a human mandible two additional finite element models were generated: a mandibular model with mesioangular impaction and second model with horizontal impaction. To investigate the stress distribution to the mandible, and tooth displacement eruptive force of 10 grams was applied.High concentration of stresses was seen at the inferior border of the mandible and lowest concentration of stress was present at symphysis for both the models. The tooth displacement for both mesio-angular and horizontal impaction caused mesial tilting of all the teeth i.e. from 2 molar to central incisor; with greatest tilting of 2 molar. Along the vertical plane, there was extrusion seen with 2 molar with mesio-angular impaction and extrusion in 2 molar and 1 molar with horizontal impaction And all the teeth exhibited buccal flaring in case of both impaction. There is significant level of tooth displacement from 2 molar towards the incisors. These changes occurring along the dental arch must be taken into consideration while planning for prophylactic extraction of third molars.

Thermo-kinetic orientation study on interface behavior of polycrystalline Cu-Nb composite by crystal plasticity finite element method

In this work, a 3-dimensional (3D) crystal plastic finite element method (CPFEM) combined with the qualitative analysis of slip thermodynamics and kinetics is applied to study the co-deformation behavior of heterophase interface and its relationships with the initial grain orientation or misorientation upon compression of FCC/BCC Cu-Nb polycrystalline metal matrix composites (MMCs). The present simulations well predict the interface instability of the 5-layered polycrystalline Cu-Nb composites arising from the onset and aggregation of the non-crystallographic bandlike concentrated strain. Meanwhile, by changing the grain orientation, the suppression or promotion of plastic shear localization can be realized, where the occurrence of interface instability depends not only on inhomogeneous stress fields, i.e., a single thermodynamic factor, but also on an implicit kinetic factor, i.e., misorientation. On this basis, a so-called artificial “coding” strategy by translating orientation-inhibited strain localization into implicit thermodynamic and kinetic information is presented to tailor the Cu-Nb MMCs, i.e., triggering as much plastic slip as possible from a thermodynamic perspective, while narrowing the misorientation as much as possible from a kinetic selection.

Dynamic Analysis of Historical Masonry Arch Bridges under Different Earthquakes: The Case of Murat Bey Bridge

Historical structures, which constitute an important part of our cultural heritage, should be well protected and carried into the future. Masonry arch bridges are significant part of these structures. In this study, the single-span Murat Bey Bridge in the province of Kütahya, built in 1460, was studied as a numerical application. Firstly, three dimensional finite element model of the bridge was constituted with SAP2000 finite element program. Static analysis of the bridge under its own weight was carried out. The modal analysis method was used to obtain the dynamic characteristics of the bridge. Then, time-history analysis method was applied for seismic evaluation of the bridge. For this purpose, the acceleration records of the 1998 Adana, 2003 Bingöl, 2011 Van and 2020 Elazığ earthquakes were taken into consideration. As a result of the dynamic analyses carried out, the displacement and stress graphs occurring on the bridge were examined. The highest displacement and stress values on the historical bridge were obtained from the acceleration records of the 2011 Van earthquake.

Delamination in GLARE laminates subjected to oblique low velocity impact considering friction

Study of oblique low velocity impact and the subsurface delamination caused in fibre metal laminates is not well reported in literatures. The present paper numerically investigates the oblique low velocity impact behaviour of clamped GLARE plates by a spherical impactor to study the influence of obliquity and coefficient of friction on the impact mechanism and on the extent of interfacial delamination. A three dimensional finite element formulation employing Newmark-β method has been developed for analyzing the oblique contact impact response of GLARE plate where Hertzian contact model is used for the normal component of contact and Mindlin and Deresiewicz theory is used for the tangential component. Results show that besides impactor velocity, obliquity of incidence and the coefficient of friction significantly influence the contact force history, contact duration and the delamination at the interfaces. In addition, the oblique angle also decides the instant and duration of reversal of tangential contact force where increasing obliquity leads to delayed instant and reduced duration of such reversal.

Mitigation of subway-induced low-frequency vibrations using a wave impeding block

The effective control of low-frequency vibrations induced by subway operation remains a problem, but wave impeding blocks (WIBs) have the potential to solve this issue. To investigate the vibration isolation behavior of WIB under subway loading, this study established a coupled track-tunnel-ground-WIB model using the two-and-a-half dimensional finite element method (2.5D FE). The effect of bedrock on wave propagation was first revealed by analyzing the eigenfrequencies of the soil layer with a tunnel. It was found that the bedrock reduced ground-borne vibrations with a frequency lower than the cut-off frequency of the soil layer. Based on this observation, the vibration isolation behavior of the WIB with different locations, embedding depths, material types, and dimension parameters was analyzed in detail. The WIB located beneath the tunnel invert (near-field active vibration isolation) exhibits a completely different behavior than that beneath the ground surface (far-field passive vibration isolation). The former can reduce ground vibrations in the entire ground surface, whereas the latter only works in a limited region directly above the WIB. The far-field vibration isolation effect is not sensitive to the vibration frequency and embedding depth, but the WIB dimension and rigidity have a significant impact. The near-field vibration isolation effect is most significantly influenced by the embedding depth, followed by the material property and dimension parameter. The WIB installed beneath the tunnel invert with a thinner embedding depth and stiffer rigidity more effectively isolates low-frequency vibrations induced by the subway.