A Parameterized Ultrasound-Based Finite Element Analysis of the Mechanical Environment of Pregnancy

Preterm birth is the leading cause of childhood mortality and can lead to health risks in survivors. The mechanical functions of the uterus, fetal membranes, and cervix have dynamic roles to protect the fetus during gestation. To understand their mechanical function and relation to preterm birth, we built a three-dimensional parameterized finite element model of pregnancy. This model is generated by an automated procedure that is informed by maternal ultrasound measurements. A baseline model at 25 weeks of gestation was characterized, and to visualize the impact of cervical structural parameters on tissue stretch, we evaluated the model sensitivity to (1) anterior uterocervical angle, (2) cervical length, (3) posterior cervical offset, and (4) cervical stiffness. We found that cervical tissue stretching is minimal when the cervical canal is aligned with the longitudinal uterine axis, and a softer cervix is more sensitive to changes in the geometric variables tested.

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Biomechanics of Calcaneus Impacted by Talus: A Dynamic Finite Element Analysis

10.21203/rs.3.rs-600528/v1 ◽

2021 ◽

Author(s):

Mengquan Huang ◽

Bin Yu ◽

Yubiao Li ◽

Chunlai Liao ◽

Jun Peng ◽

...

Keyword(s):

Finite Element ◽

Articular Surface ◽

Three Dimensional ◽

Peak Stress ◽

Lateral Wall ◽

Element Model ◽

Calcaneal Fracture ◽

Element Analysis ◽

Average Maximum ◽

The Impact

Abstract BackgroundThe biomechanics of calcaneus impacted by the talus are unclear. We aimed to evaluate the biomechanical effect of the talus impacting on the calcaneus at different falling speed, and analyze the factors affecting calcaneal fracture.Methods A finite element model including the talus, calcaneus and ligaments was built using a variety of three-dimensional reconstruction software. The method of explicit dynamics was used to analyze the process of the talus impacting the calcaneus. Stress values of the posterior, middle, and anterior subtalar articular surface(PSAS, ISAS, ASAS), the calcaneocubic articular surface(CAS), the bottom of the calcaneus(BC), the medial wall (MW)and lateral wall (LW) of the calcaneus were extracted. Stress quantity and distribution changes in various parts of the calcaneus changed with speed were analyzed.ResultsPosterior subtalar articular surface reached the peak stress first during the process of talus impacting the calcaneus. The stress was mainly concentrated on the PSAS, ASAS, MW and GA. Comparing with the speed of 5m/s, the average maximum stress increased in each region of the calcaneus were: PSAS 73.81%, ISAS 7.11%, ASAS 63.57%, GA 89.10%, LW 140.16%, CAS 140.58%, BC 137.67%, MW 135.99% at a speed of 10m/s. The regions where the stress were concentrated changed, and the magnitude and sequence of stress peaks of calcaneus changed with speed also during the impact.Conclusion The falling speed affected the value and distribution of stress of the calcaneus, which was the most important factor leading to a calcaneal fracture. The magnitude and sequence of stress peaks might be important factors in determining the beginning and direction of fracture lines.

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Understanding the impact of train run-throughs on railway switches using finite element analysis

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409718795759 ◽

2018 ◽

Vol 233 (4) ◽

pp. 359-369 ◽

Cited By ~ 2

Author(s):

JY Shih ◽

H Hemida ◽

E Stewart ◽

C Roberts

Keyword(s):

Finite Element ◽

Three Dimensional ◽

Element Model ◽

Element Analysis ◽

Dimensional Finite Element ◽

Designed Experiment ◽

Explicit Analysis ◽

Three Dimensional Finite Element ◽

Failure Location ◽

The Impact

Train run-throughs on railway switches is a special issue, where a train passes through non-trailable railway switches in the wrong direction. This has the potential to cause severe damage and can lead to derailment. In order to understand the impact of train run-throughs on railway switches, a three-dimensional finite element model using explicit analysis has been developed. A detailed switch model has been developed that includes all key components: stretcher bars, supplementary drive and point operating equipment. The model was validated through a specifically designed experiment where switch run-throughs were emulated on a real switch; a good agreement was found between the experimental data and the model. The model has been used to make an assessment of the locking mechanisms. The forces in each component have been assessed and investigated, and the observations of failure location and component during run-through analysis are indicated. During a run-through, the supplementary drive rod and stretcher bar encounter a significant plastic deformation, and it is recommended that they should be redesigned in order to avoid plastic behaviour.

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Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

Tire Science and Technology ◽

10.2346/1.2137526 ◽

1996 ◽

Vol 24 (4) ◽

pp. 339-348 ◽

Cited By ~ 3

Author(s):

R. M. V. Pidaparti

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Composite Structures ◽

Three Dimensional ◽

Element Model ◽

Torsional Stiffness ◽

Element Analysis ◽

Rubber Belt ◽

Steel Cord ◽

Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

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Finite Element Analysis of Nonuniformity of Tires with Imperfections5

Tire Science and Technology ◽

10.2346/1.2768607 ◽

2007 ◽

Vol 35 (3) ◽

pp. 226-238 ◽

Cited By ~ 1

Author(s):

K. M. Jeong ◽

K. W. Kim ◽

H. G. Beom ◽

J. U. Park

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Three Dimensional ◽

Element Model ◽

Radial Force ◽

Element Analysis ◽

The Finite Element Analysis ◽

Dimensional Finite Element ◽

Force Variation ◽

Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽

10.3390/ma14051152 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1152

Author(s):

Rafał Nowak ◽

Anna Olejnik ◽

Hanna Gerber ◽

Roman Frątczak ◽

Ewa Zawiślak

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Three Dimensional ◽

Element Model ◽

Rapid Maxillary Expansion ◽

Stress Distributions ◽

Maxillary Expansion ◽

Facial Skeleton ◽

Element Analysis ◽

Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

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The Optimum Cage Position and Orientation on the ALIF with Facet Screw Fixation: A Finite Element Analysis and the Taguchi Method

Journal of Mechanics ◽

10.1017/jmech.2011.25 ◽

2011 ◽

Vol 27 (3) ◽

pp. 309-320 ◽

Cited By ~ 1

Author(s):

C.-Y. Fan ◽

C.-K. Chao ◽

C.-C. Hsu ◽

K.-H. Chao

Keyword(s):

Finite Element ◽

Taguchi Method ◽

Screw Fixation ◽

Three Dimensional ◽

Element Model ◽

Lateral Position ◽

Element Analysis ◽

Control Factors ◽

Position And Orientation ◽

Noise Factors

ABSTRACTAnterior Lumbar Interbody Fusion (ALIF) has been widely used to treat internal disc degeneration. However, different cage positions and their orientations may affect the initial stability leading to different fusion results. The purpose of the present study is to investigate the optimum cage position and orientation for aiding an ALIF having a transfacet pedicle screw fixation (TFPS). A three-dimensional finite element model (ALIF with TFPS) has been developed to simulate the stability of the L4/L5 fusion segment under five different loading conditions. The Taguchi method was used to evaluate the optimized placement of the cages. Three control factors and two noise factors were included in the parameter design. The control factors included the anterior-posterior position, the medio-lateral position, and the convergent-divergent angle between the two cages. The compressive preload and the strengths of the cancellous bone were set as noise factors. From the results of the FEA and the Taguchi method, we suggest that the optimal cage positioning has a wide anterior placement, and a diverging angle between the two cages. The results show that the optimum cage position simultaneously contributes to a stronger support of the anterior column and lowers the risk of TFPS loosening.

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Finite Element Analysis of the Effect of Surface Hardening Depth in Port Crane Wheel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.3282 ◽

2011 ◽

Vol 291-294 ◽

pp. 3282-3286 ◽

Cited By ~ 1

Author(s):

Jiang Wei Wu ◽

Peng Wang

Keyword(s):

Finite Element ◽

Surface Hardening ◽

Three Dimensional ◽

Element Model ◽

Contact Stresses ◽

Numerical Results ◽

Element Analysis ◽

Finite Element Software ◽

Dimensional Finite Element ◽

Three Dimensional Finite Element

In port crane industry, the surface hardening technique is widely used in order to improve the strength of wheel. But the hardening depth is chosen only by according to the experience, and the effect of different hardened depths is not studied theoretically. In this paper, the contact stresses in wheel with different hardening depth have been analyzed by applying three-dimensional finite element model. Based on this model, the ANSYS10.0 finite element software is used. The elastic wheel is used to verify the numerical results with the Hertz’s theory. Three different hardening depths, namely 10mm, 25mm and whole hardened wheel, under three different vertical loads were applied. The effect of hardening depth of a surface hardened wheel is discussed by comparing the contact stresses and contact areas from the numerical results.

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Nonlinear Finite Element Analysis of Super-Long Pile and Soil Interaction in Soft Soil

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.201-203.1601 ◽

2011 ◽

Vol 201-203 ◽

pp. 1601-1605 ◽

Cited By ~ 2

Author(s):

Shang Ping Chen ◽

Wen Juan Yao ◽

Sheng Qing Zhu

Keyword(s):

Finite Element ◽

Constitutive Model ◽

Soft Soil ◽

Three Dimensional ◽

Nonlinear Behavior ◽

Element Model ◽

Element Analysis ◽

Friction Resistance ◽

Tip Resistance ◽

Side Friction

In this paper, a nonlinear three-dimensional finite element model for super-long pile and soil interaction is established. In this model, contact elements are applied to simulate the nonlinear behavior of interaction of super-long pile and soil. A nonlinear elastic constitutive model for concrete is employed to analyze stress-strain relation of pile shaft under the axial load and the Duncan-Chang’s nonlinear constitutive model is used to reflect nonlinear and inelastic properties of soil. The side friction resistance, axial force, pile-tip resistance, and developing trend of soil plastic deformation are obtained and compared with measured results from static load tests. It is demonstrated that a super-long pile has the properties of degradation of side friction resistance and asynchronous action between side and pile-tip resistance, which is different from piles with a short to medium length.

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Finite Element Analysis of Top-Hat–Stiffened Panels of Fiber-Reinforced–Plastic Boat Structures

Marine Technology and SNAME News ◽

10.5957/mt1.2007.44.1.16 ◽

2007 ◽

Vol 44 (01) ◽

pp. 16-26

Author(s):

Ömer Eksik ◽

R. Ajit Shenoi ◽

Stuart S. J. Moy ◽

Han Koo Jeong

Keyword(s):

Finite Element ◽

Lateral Pressure ◽

Three Dimensional ◽

Element Model ◽

Stiffened Panel ◽

Element Analysis ◽

Stiffened Panels ◽

Fiber Reinforced Plastic ◽

Reinforced Plastic ◽

Experimental Findings

This paper describes the development of a finite element model in order to assess the static response of a top-hat-stiffened panel under uniform lateral pressure. Systematic calculations were performed for deflection, strain, and stress using the developed model based on the ANSYS three-dimensional solid element (SOLID45). The numerical modeling results were compared to the experimental findings for validation and to further understand an internal stress pattern within the different constituents of the panel for explaining the likely causes of the panel failure. Good correlation between experimental and numerical strains and displacements was achieved.

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New Design Procedure of Transtibial ProsthesisBed Stump Using Topological Optimization Method

Symmetry ◽

10.3390/sym12111837 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1837 ◽

Cited By ~ 1

Author(s):

Martin Sotola ◽

David Stareczek ◽

David Rybansky ◽

Jiri Prokop ◽

Pavel Marsalek

Keyword(s):

Finite Element ◽

Three Dimensional ◽

Design Procedure ◽

Optimization Method ◽

Topological Optimization ◽

Element Analysis ◽

Current Application ◽

Transtibial Prosthesis ◽

Walking Biomechanics ◽

The Impact

This paper presents a new design procedure for production of a transtibial prosthesis bed stump by three-dimensional (3D) printing with topological optimization. The suggested procedure combines the medical perspective with finite element analysis and facilitates regaining the symmetry in patients with transtibial prosthesis, which leads to life improvement. The particular focus of the study is the weight reduction of the lower part of the bed stump, while taking into account its stiffness and load-bearing capacity. The first part of the work deals with the analysis of the subject geometry of the bed stump, which is usually oversized in terms of the weight and stiffness that are necessary for the current application. In the second part, an analysis of walking biomechanics with a focus on the impact and rebound phases is presented. Based on the obtained information, a spatial model of the lower part of the bed stump is proposed in the third phase, in which the finite element method is described. In the fourth part, the topological optimization method is used for reducing the structure weight. In the last part, the results of the designed model are analyzed. Finally, the recommendations for the settings of the method are presented. The work is based on the practical industry requirements, and the obtained results will be reflected in the design of new types of transtibial prosthesis.

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