FEA Studies Research Articles

Finite element analysis in the Dental Sciences: A Bibliometric and a Visual Study

Introduction and aimsFinite element analysis (FEA) is an incrementally practical and precise tool for the prediction of stress effects on different tissue structures and has therefore interested dental researchers for decades. This bibliometric and visualized study was aimed to assess the research progress related to FEA in the dental sciences in terms of research trends and frontiers. MethodsThe articles about FEA studies in this field during 1999 to 2024 were obtained from Web of Science Core Collection. Then, these results were analysed and plotted using Microsoft Excel, VOSviewer, and CiteSpace in order to find out the historical evolution, current hotspots, and future directions. ResultsTotal 2838 literature records related to the topic were retrieved from Web of Science Core Collection. The most active country and institution were USA (538 documents) and Universidade Estadual Paulista (140 documents), respectively. Baggi et al from University of Naples Federico II was the author with the most highly cited article (352 citations), which was published on the Journal of Prosthetic Dentistry in 2008. Dental Materials ranked first (231 documents) among the 10 journals with the greatest numbers of relevant publications. The top three trending keywords were ‘dental implant’, ‘stress distribution’, and ‘fracture’. The endocrown, clear aligner, and posterior edentulism were scientific frontiers in this field. ConclusionThe present study provides a comprehensive bibliometric analysis of research in the dental science by FEA approaches, which will identify active hotspots of scientific interest to guide further research endeavours.

Design optimization and failure analysis of natural composite sandwich T-joints under pulling load conditions

This paper presents a structural analysis of composite sandwich T-joint systems respond to pulling loads. A finite element (FE) model of the T-joint structure was created with four geometrical models, and three different materials were used to compare the design and identify the failure locations. The stress-critical regions were identified within and beneath the Stringers, which are responsible for connecting the base and web panels and transferring loads. The FEA studies showed that T-joint fails due to high shear stress in the stringer, base panel (flange), web, and bolted joint areas. The combination of shear and tensile stress in the adhesive layer between the composite base panel and the stringers lead to failure. Furthermore, incorporating a circular hole in the web panel near the joint resulted in an 11.8 % reduction of failure load. Due to the intricate stress distribution and geometric variations in these joints, premature failure can occur. Therefore, meticulous attention is essential for wing structures at spar joints, especially under extreme load conditions. Despite the complex manufacturing process, the present conventional T-joint design is extremely effective. However, other designs for low-cost manufacturing were proposed and evaluated. The investigation determined that the sandwich structure exhibits a shear stress of 28.88 MPa and von Mises stresses of 57.75 MPa. These values are higher than those observed in design cases 1 and 2. Therefore, design case 3 is suitable for aeronautical applications.

Cross laminated timber geometry and joinery implications on low-frequency sound transmission: FEA and Laser Doppler Vibrometry studies

Cross Laminated Timber (CLT) slabs are becoming more widespread in North American construction in large part because of the environmental advantage of lower embodied carbon when compared to concrete and steel slabs. This advantage is significantly reduced by the use of high embodied carbon layers in the mass timber floor assemblies, such as concrete or gypsum screeds, that are used to reduce the direct sound transmission. This paper presents a study on the potential to reduce low-frequency sound transmission in cross-laminated timber floors by means of geometric stiffness. A laser doppler vibrometry (LDV) experiment on two different geometries is presented. One sample has a flat geometry, the other has a folded plate design. The folded plate sample is built with the same CLT panels used on the flat one, but is made out of 12 custom parts assembled into a domical shape. Both samples were installed on a 6 × 7 foot glulam frame, subjected to shaker excitations in the low frequencies on their top side, and the vibration on their bottom sides measured with the LDV. The resulting data is used to calibrate an FEA model, and subsequently study the sound transmission implications of the sample’s boundary conditions and joinery.

Investigation of Vertical Stiffness of the Front Axle Air Springs for Passenger Bus by Experimental and Finite Element Analysis

Air Springs have been used for years, especially in commercial vehicles and buses, to maintain the vehicle's height regardless of the load and increase vehicle comfort. It is complex to experimentally determine the changes (reaction force, extension, strain) caused by loading alone to fully interpret the damping ability of air springs under operating conditions. The air springs are exposed to tension and force in different directions as they are made of a rubber composite structure. Therefore, discussing the damping properties of air springs with only the experimental method is difficult. The study aims to obtain information about the damping behavior of the bellows produced from composite materials, such as bellows under static loads, using both experimental and finite element analysis models. The finite element model of the air springs was obtained by modeling the three parts that provide its integrity. The material definitions required for the composite structure were determined by experimental methods and entered into the FEA program. No material is defined for rigid body members. The results of unidirectional and multidirectional tensile tests performed in a laboratory environment were used for material properties. The characteristics of the air were also entered into the analysis software with the information taken from the literature. The analyzes were carried out in three steps inflating the bellows to the specified pressure values, vertical movement, and compression to the specified displacement value. In this study, it was seen that the cord fabrics in rubber composite structures were affected more by excessive tension than rubber material, and the deviation of the static stiffness value was approximately 5% between the experimental study and the analysis studies. Thanks to FEA studies, it has been determined that more results can be obtained regarding values such as regional stress, force, and displacement in the bellows.

Can neck fractures in proximal humeri be predicted by CT-based FEA?

Background:Proximal humeri fractures at anatomical and surgical neck (∼5% and ∼50% incidence respectively) are frequent in elderly population. Yet, neither in-vitro experiments nor CT-based finite element analyses (CTFEA) have investigated these in depth. Herein we enhance (Dahan et al., 2019) (addressing anatomical neck fractures) by more experiments and specimens, accounting for surgical neck fractures and explore CTFEA’s prediction of humeri mechanical response and yield force. Methods:Four fresh frozen human humeri were tested in a new experimental configuration inducing surgical neck fractures. Digital image correlation (DIC) provided strains and displacements on humeri surfaces and used to validate CTFEA predictions. CTFEA were enhanced herein to improve the accuracy at the proximal neck: A cortical bone mapping (CBM) algorithm was implemented to overcome insufficient scanning resolution, and a new trabecular material mapping was investigated. Results:The new experimental setting induced impacted surgical neck fractures in all humeri. Excellent DIC to CTFEA correlation in strains was obtained at the shaft (slope 0.984, R2=0.99) and a fair agreement (slope 0.807, R2=0.73) at the neck. CBM algorithm had worsened the correlation, whereas the new material mapping had a negligible influence. Yield loads predictions improved considerably when trabecular yielding (maximum principal strain criterion) was considered instead of surface cortical yielding. Discussion:CTFEA well predicts strains on the shaft and reasonably well on the neck. This enhances former conclusions by past studies conducted using SGs, now also evident by DIC. Yield load prediction for surgical neck fractures (involving crushing of trabecular bone) is predicted better by trabecular failure laws rather than cortex ones. Further FEA studies using trabecular orthotropic constitutive models and failure laws are warrant.

Reporting guidelines for in-silico studies using finite element analysis in medicine (RIFEM)

BackgroundTo the best of our knowledge, there are no reporting guidelines for design, conduct and reporting of Finite Element studies in health sciences. We intend to propose specific and detailed guidelines for reporting these studies. MethodAfter recognizing the need to have uniform guidelines for reporting of finite element analysis in medicine and dentistry, a group of 5 researchers working on FEA as their research area met in the summer of 2020 and drafted the methodology for the development of such guidelines. Each researcher individually made a list of major headings required for reporting these studies and met again in September 2020 to finalize the domains. Subsequently, sub headings and details were charted. The draft list of items for reporting the guidelines were presented to a larger team of 15 experts and some changes were further made based on their inputs. ResultsThe guidelines entail seven major domains and their sub-domains, including parameters for model structure, segmentation, mesh structure, force application and model validation, etc. This checklist aims to improvise the reporting and consistency of FEA studies. ConclusionWe hope that the usage and adoption of these guidelines by the scientific community would result in more thoughtful and uniform documentation. Also, the confidence in the results would be enhanced through model reproducibility, reusability and accountability. The proposed guidelines were named as ‘Reporting of in-silico studies using finite element analysis in medicine’ and the term ‘RIFEM’ was used as acronym.

Finite Element Analysis of Biomechanical Behaviour of Remaining Coronal Dentin in Endodontically Restored Tooth - A Systematic Review [Evaluation of Stress Distribution in FEA Studies

Background: Since few years finite element (FE) analysis has turn out to be a widespread tool for investigators seeking to simulate the tooth biomechanics and associated structures. Finite element method plays important role to expand understanding of the ferrule effect. This paper contains a systematic review and conclusions from FE method grounded computational simulations of the the tooth with post and core to simulate function and tissue behavior
 Methods: 14 applicable papers were linked within this systematic literature search. Uprooted data contained information on type of tooth, location of tooth, magnitude of force, software used for modelling, boundary condition, method of scanning, validation, tooth with ferrule, tooth without ferrule, key findings.
 Results: Included papers illustrated use of FE analysis for replication of including nonlinear tooth and tissue mechanics, contact analysis and rigid body movements. We executed multi-database systematic review through PRISMA standards accomplishing inclusion criteria and results were investigated and précised for appropriate papers.
 Discussion: With prompt expansions of computer knowledge, the FEA now recognized as a potent method in dental biomechanics due to its flexibility in measuring stress dispersals within multidimensional structures. The researcher will be well equipped to understand the results of FEA investigations and correlate these results to clinical settings after learning the basic theory, application, method, and limitations of FEA in dentistry. Ferrule has a precarious impact on stress reduction. Teeth are less stressed when posts and cores are composed of strong materials. Keeping supragingival tooth structure included within the crown gives repaired teeth extraordinary strength.

EFFECT OF ORIENTATION DISTANCE ON TEMPERATURE INDUCED PROBLEMS IN MULTI-PART MANUFACTURING BY SELECTIVE LASER MELTING

SLM methods are widely used to manufacture metal parts for functional use in mainly automotive, aerospace and medical industries. Besides many advantages of SLM, manufacturing times take long times and need many costs. In this study, nine samples were manufactured at the same time to set a scenario of multiple samples manufacturing and providing highly productive conditions. Some manufacturing problems such as internal stresses and dimensional distortions occurred during manufacturing. These problems were the result of heterogeneous temperature gradients and geometrical properties. FEA studies were carried out by “Netfabb Ultimate Simulation LT 2019”. Temperature changes were observed, and relations among these temperature changes, residual stresses, as well as dimensional distortions were evaluated. As a result, the orientation distance of samples was an important parameter due to residual stress and displacement. Unsuitable positioning distance between samples caused high dimensional distortion, macro cracks and residual stress. The plastic strain equation was correlated according to the results of the analysis with 7% difference (regression) to define the optimum distance between parts.

Metamaterials with a controllable thermal-mechanical stability: Mechanical designs, theoretical predictions and experimental demonstrations

Mechanical metamaterials with tunable thermal expansion are of increasing interest due to their capability for matching the thermal expansion of surrounding components to maintain high-level thermal-mechanical stability upon a temperature change and show their promising applications in the fields of flexible electronics, aerospace, MEMS, and precision instruments. Though numerous of studies on metamaterials with zero thermal expansion of coefficient (CTE) has been developed to access these demands, the experimentally demonstrated designs with a remarkable zero CTE value (e.g. <0.5 ppm/K) still remain a challenge. In this paper, a design concept of metamaterial capable of offering a tailorable CTE, especially the excellent thermal-mechanical stability, is systematically studied, whose underlying mechanism is the conversion of thermal-induced deflection of bilayer beams (in Al and Ti) into unusual, effective thermal expansion or shrinkage of metamaterials. Notably, the experimentally demonstrated CTE of this metamaterial is 0.42 ppm/K, which is the unprecedented zero CTE result as compared to the previously reported studies. The theoretical model for CTE and elastic modulus of this design, which is verified by FEA and experiments, provides a clear understanding of relationships between configuration parameters and effective thermal and mechanical performances. Combined theoretical predictions, FEA, and experimental studies demonstrate the capability of this metamaterial to serve as a design platform for devices or components that require excellent thermal-mechanical stability.

Simulation Based Design Analysis of Pressure Chamber for Metrological Applications up to 200 MPa

In the high pressure applications, safety and handling of the design parts are crucial and essentially required. If the design parameters are not properly optimized, sometimes it leads to fatal accidents or huge money loss. With the advent of modern computational tools, the simulation based design analysis is now a day’s address above issues amicably to ultimately helping to improve development process and final product. The paper describes the step by step design process and simulation analysis of the pressure chamber. The theoretical FEA studies carried out on the designed pressure cell show that the chamber is working smoothly within the desired pressure range from atmospherics pressure to 200 MPa based on safety factor of the material used. Such devices are mostly imported and not available indigenously. Thus, the fabrication of simulated device is one step forward to develop an import substitute item and promote ‘Make in India’ product. Simulated results are found to quite encouraging. The actual experiments on the fabricated pressure cell would be performed in due course of time.

COMPARISON OF THE EFFECT OF DIFFERENT IMPLANT CONNECTIONS ON STRESS DISTRIBUTION AROUND DENTAL IMPLANTS (IN VITRO STUDY)

INTRODUCTION: In implant dentistry literature, the commonly used materials in FEA studies can be classified as either implant, peri-implant bone (cortical and cancellous bone), and restoration. This method allows application of simulated forces at specific points in the system and stress analysis in the peri-implant region and surrounding structures. The implant connection system and other factors as the prosthesis type, length and material of restoration have a great effect on stresses falling on the bone around implant OBJECTIVES: was to evaluate and calculate the stress distribution with finite element analysis between implant in optimum apicocoronal position and implant in 6 mm vertical defect as well as between Internal Hex and Morse Taper connections. MATERIAL AND METHODS: In this study the stresses falling on surrounding bone, abutment, fixture and screw were analyzed in the two different configurations. In the first configuration, the jawbone has no defects. It is composed starting from the top of the bone, of 1 mm layer of crestal cortical bone, 3.5 mm layer of cancellous bone, 0.5 mm sinus cortical bone and a bottom layer of graft bone. In the second configuration, a vertical bone defect was created. The implants examined throughout this study were titanium implant with Morse taper and internal hex connections.

Effects of abutment screw preload in two implant connection systems: A 3D finite element study

Statement of problemFinite element analysis (FEA) has been used to evaluate the biomechanical behaviors of dental implants. However, in some FEA studies, the influence of the preload condition has been omitted to simplify the analysis. This might affect the results of biomechanical analysis significantly. The preload condition requires analysis. PurposeThe purpose of this FEA study was to evaluate and verify the effects of the presence of the preload condition on abutment screws under the occlusal load for external and internal hexagonal connection systems. Material and methodsThe finite element models consisting of bone blocks, 2 different implant systems (Osstem US and GS system; Osstem Implant Co), and crowns were created. With these components, a total of 6 models with different conditions were constructed for FEA: external hexagonal connection system only with preload (EO), external hexagonal connection system with no preload but occlusal load (EN), external hexagonal system with both preload and occlusal load (EP), internal hexagonal system only with preload (IO), internal hexagonal system with no preload but occlusal load (IN), and internal hexagonal system with both preload and occlusal load (IP). An 11.3-degree oblique load (100 N) to the axis of the implant was applied on the occlusal surface of the crown for the models with occlusal load. A preload of 825 N was applied in the abutment screw of the models EO, EP, IO, and IP. The maximum von Mises stress, maximum principal stress, and maximum displacement of the components of the models were evaluated. ResultsBoth external and internal connection systems resulted in higher maximum von Mises stress and maximum principal stress values in the presence of preload in the abutment screw. The internal connection system showed higher displacement values than the external system with or without occlusal loading, and values tended to increase with the preload condition. ConclusionsThe presence of a preload condition significantly affected the biomechanical behaviors of the components of 2 different connection systems. The preload condition should be included in FEA to achieve more realistic results.

Application of Finite Element Model in Implant Dentistry: A Systematic Review.

FEM was technologically innovated which initially aimed at answering structural analysis difficulties involving Mechanics, Civil and Aeronautical Engineering. FEM basically stands for a numerical model of analyzing stresses as well as distortions in the form of any agreed geometry. There for the shape is discretized into the so-called ‘finite elements’ coupled through nodes. Accuracy of the results is determined by type, planning and total number of elements used for a particular study model. 3-D FE model was designed for in-depth qualitative examination of the relations amongst implant, tooth, periodontal ligament, and bone. Scholarly work equating work reliability, validated with a 3-D modeling suggested that meticulous data can be acquired with respect to stress distribution in bone. Comparative results from 3-D FEA studies showed that 3D FEA, when matched with in-vivo strain gauge measurements were corresponding with clinical outcomes. The aim of this review of literature is to provide an overview to show the application of FEM in (Short) implant dentistry.

A Review on Application of Bellows Expansion Joints and Effect of Design Parameters on System Characteristics

Objectives: A bellows expansion joint is an assembly of two or more bellows which help to tackle expansion or contraction in the system where it is designed to fit in. It was found, various independent researchers did lot of research in the design and geometry of bellows expansion joint but a review of all is scare, we have put forth the different possible features of bellows design in this paper. Methods/Analysis: The bellows, consisting of one or more convolutions, are designed to offer further agility in the configuration of piping structures and pressure vessel applications involving thermal expansion and relative movement in system. Numerous researchers have conducted studies on bellows expansion joints with the help of standards such as ASME and EJMA. They have wide applications and are understood as a significant. Thus various parameters pertaining to the design of bellows expansion joints, which affect the characteristics of the system, have been reviewed. Findings: From this review, it can be said that for all the design condition, there was not bellow geometry or design parameters are superior. Under such designs based on the standards, it is expected to perform exhaustive analysis involving sound engineering judgment. Meanwhile, the choice of bellows expansion joint is sufficiently broad depending upon the applications. Improvement: Certainly there is still room for new design principles and analysis based on analytical, experimental and FEA studies. Particularly, study of bellows subjected to torsions may be done as little is found in the literature and the existing standards.

Evaluation of a Mixed CAD Gear Modeling from Time and Precision Point of View

Abstract The aim of the paper is to present an evaluation of a new mixed CAD modeling method, capable to universally build surfaces and solid models of gears. The proposed CAD solution builds gear models, primary not for a visual simulation of the gearing processes, but for complex gearing- and FEA studies in virtual environment. Localization of the contact paths of gear pairs, virtual kinematic evaluations, rapid verification of newly developed gear types and FEA analysis requires satisfactorily precise surface and solid models. The known NURBS modeling methods are mainly based on the analytical equations of the flanks of the teeth surfaces. The bottom and tip surfaces of the teeth, are very important in meshing and FEA studies, and generally cannot be built from the meshing equations. As the new mixed modeling method proposes a simplified and quick CAD modeling procedure, with flexible modeling options like rapid tool profile modifications, an evaluation of the obtained models must be made, from both: generating time and precision point of view. For this purpose, a model of a spur cylindrical gear (generated by a convolute helical hob) is built using the Solid Boolean Subtraction method and is compared with the gear generating process using a new mixed CAD method.

Mixed CAD Method to Develop Gear Surfaces Using the Relative Cutting Movements and NURBS Surfaces

Abstract The paper proposes a pure CAD modeling solution to universally generate surfaces and solid models of gears, which are intended to be used in contact and FEA studies in virtual environment. The developed method uses the known NURBS surfaces modeling methods, combined with the input in CAD environment of the relative cutting motions between tool and gear. The cutting motions are also divided in relative motion steps, the cutting tool profiles are reduced to discreet points, fixed in 3dpolyline vertexes, and theirs coordinates are read and stored after each moving steps. The obtained points contain discreet points from the generated surfaces. Using this points, and usual NURBS modeling methods, the generated surfaces are built. In final stage, this method should be a much faster alternative to the very slow, and huge calculating power consuming, solid modeling with Boolean operations.

The 3D Eyeball FEA Model with Needle Rotation

Definition of the force and torque boundaries during ophthalmic operations is a vital step towards design and development of robotic solutions for eye surgery. This paper describes the development of an eyeball FEA model. Unlike other eyeball FEA studies, this 3D eyeball model contains all three layers of the inner eye: retina, choroid and sclera. Furthermore the model includes six extra ocular muscles. The intraocular rotation of a needle tool using a trocar during the surgery was also considered in this study. Although variables such as the thickness of the layers and the property of the orbits and the muscles are unique for every individual, the model was developed by introducing some assumptions and constraints for an average eye. However by changing few parameters a modified model suitable for individuals can be generated. The model gives the stress distribution when the needle rotates inside the eyeball. The results of this study will give a numerical understanding of the forces which are needed for ophthalmic operation.

Biomechanical comparison of two different collar structured implants supporting 3-unit fixed partial denture: A 3-D FEM study

Objective. The purpose of the study was to compare the effects of two distinct collar geometries of implants on stress distribution in the bone as well as in the fixture-abutment complex, in the framework and in the veneering material of 3-unit fixed partial denture (FPD). Material and methods. The 3-dimensional finite element analysis method was selected to evaluate the stress distribution in the system composed of 3-unit FPD supported by two different dental implant systems with two distinct collar geometries; microthread collar structure (MCS) and non-microthread collar structure (NMCS). In separate load cases, 300 N vertical, 150 N oblique and 60 N horizontal, forces were utilized to simulate the multidirectional chewing forces. Tensile and compressive stress values in the cortical and cancellous bone and von Mises stresses in the fixture-abutment complex, in the framework and veneering material, were simulated as a body and investigated separately. Results. In the cortical bone lower stress values were found in the MCS model, when compared with NMCS. In the cancellous bone, lower stress values were observed in the NMCS model when compared with MCS. In the implant-abutment complex, highest von Mises stress values were noted in the NMCS model; however, in the framework and veneering material, highest stress values were calculated in MCS model. Conclusions. MCS implants when compared with NMCS implants supporting 3-unit FPDs decrease the stress values in the cortical bone and implant-abutment complex. The results of the present study will be evaluated as a base for our ongoing FEA studies focused on stress distribution around the microthread and non-microthread collar geometries with various prosthesis design.

Characterization of the transverse elongation of polymeric electrostatic actuators induced by Maxwell stress

This article gives a review of the research done in our lab over the past few years on the characterization of the transverse elongation of polymeric electrostatic actuators induced by Maxwell stress. Dielectric elastomers are known to produce large transverse strains in response to Maxwell stresses and thus provide a useful form of electromechanical actuation. The transverse strain responses of dielectric elastomer based Maxwell stress actuators have been investigated. The mechanical properties of elastomer cannot be fully understood on the basis of linear elastic theories. Models of hyperelasticity that are capable of describing the large deformation of rubber-like polymer materials have been used to interpret our experimental results. Our experimental and FEA studies on elastomer film actuators have helped us to understand how both the geometry and the material properties of the elastomers influence the observed actuation capabilities. Getting a high transverse strain requires not only good material properties, but also optimized actuator/electrode geometry. Some other factors, such as the electrode properties also influence the actuator performance.

Microchannel cooling in low material budget supports for silicon pixel detectors

Pixel detectors at future colliders will need to match very stringent requirement on position resolution. To ensure the needed mechanical stability and the removal of the power dissipated by the read-out electronic, the support structure and cooling add an important contribution to the total material in the active area, in terms of radiation length. We present the development, the construction and the mechanical–thermal characterization of prototypes of light material support for pixel detectors with microchannel for heat evacuation through forced convection of liquid coolant. The solution we choose shows several advantages: heat exchange is taking place efficiently due to the high ratio surface/volume and so high thermal conductivities can be obtained, minimally affecting the stiffness of the structure; the thermal resistances are reduced because of the contiguity between the fluid and the circuit dissipating power; the uniformity of temperature on the surface covered by of the sensors is also kept under control. Several prototypes implementing different geometries of micro-machined channels have been realized in composites materials (CFRP). FEA studies have been performed to validated the experimental test conducted in the thermo-fluid dynamic test bench we recently assembled in the INFN Pisa laboratory.