Establishing 3D Mandible FEA Model via Clinical CT Images

2010 ◽  
Vol 44-47 ◽  
pp. 1952-1956 ◽  
Author(s):  
Wen Zheng Wu ◽  
Ya Dong Chen ◽  
Kun Peng Cui ◽  
Xing Jun Qin ◽  
Wan Shan Wang
Keyword(s):  
3D Model ◽  
Biomechanical Analysis ◽  
Mandible Reconstruction ◽  
Element Analysis ◽  
Boundary Constraints ◽  
Reconstruction Surgery ◽  
Tetrahedral Meshes ◽  
Fea Model ◽  
Tetrahedral Elements ◽  
Force Range

Aiming at the filature of titanium plates and screws after defective mandible reconstruction surgery, a method named Finite Element Analysis （FEA）was conducted in this paper through FEA software Abaqus with which a 3D model of defective mandible was established. The mandible 3D model was input into the Magics and remeshed. The mandible model was output in the format of .inp file from the Magics and import to Abaqus for converting from triangular meshes to tetrahedral meshes. The tetrahedral meshes totally had 71057 tetrahedral elements and 10720 nodes. The boundary constraints of the mandible 3D model were arranged. The force was applied separately in the direction of vertical, 15° and 30° with the occluding plane (teeth force range when occluding) to analyze the force. The mandible 3D model was established and prepared to be done a biomechanical analysis.

The Optimization Design of Dental Implant after the Mandible Tumor Resection and Reconstruction

2013 ◽  
Vol 702 ◽  
pp. 318-322
Author(s):  
Wen Zheng Wu ◽  
Ji Zhao ◽  
Lei Zhang ◽  
Xing Tian Qu ◽  
Di Zhao ◽  
...  
Keyword(s):  
Optimization Design ◽  
Tumor Resection ◽  
Biomechanical Analysis ◽  
Secondary Surgery ◽  
Element Analysis ◽  
Fea Model ◽  
3D Fea ◽  
Mandible Defect ◽  
Operation Cost

Mandible defect and the lack of dentition may result in facial deformity and chewing organ defects. It happens after the surgery of oral and maxillofacial tumors. This study aims at this problem. In this study, Finite Element Analysis (FEA) was employed to reconstruct the implanted mandible for customized patient. The 3D FEA model has great importance for biomechanical analysis. Though the analysis of the biomechanical situation with different numbers of dental implants, we can optimize the location and quantity of the implants. In this way, we can improve the quality of the implants, reduce the pain of patients, reduce the operation cost and avoid secondary surgery.

Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems

1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Energy ◽  
Structural Integrity ◽  
Experimental Temperature ◽  
Temperature Profiles ◽  
Element Analysis ◽  
Drum Brake ◽  
Fea Model

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.

scholarly journals Design and Modeling of a Bio-Inspired Flexible Joint Actuator

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 95
Author(s):  
Ming Xu ◽  
Cheng Rong ◽  
Long He
Keyword(s):  
Hydraulic System ◽  
Driving Forces ◽  
Theoretical Models ◽  
Element Analysis ◽  
Flexible Joint ◽  
Fea Model ◽  
The Finite Element Analysis ◽  
Series Of Experiments ◽  
The Mathematical Model ◽  
Moving Speed

Spiders rely on a hydraulic system to stretch their legs but use muscles to make their legs flex. The compound drive of hydraulics and muscle makes an integrate dexterous structure with powerful locomotion abilities, which perfectly meets the primary requirements of advanced robots. Inspired by this hydraulics-muscle co-drive joint, a novel flexible joint actuator was proposed and its driving characteristics were preliminarily explored. The bio-inspired flexible joint manifested as a double-constrained balloon actuator, which was fabricated by the composite process of 3D printing and casting. To evaluate its performance, the mathematical model was deduced, as well as the finite element analysis (FEA) model. A series of experiments on the rotation angles, driving forces, and efficiencies of the flexible joint were carried out and compared with the mathematical calculations and FEA simulations. The results show that the accuracy of the two theoretical models can be used to assess the joint actuator. The locomotion test of a soft arthropod robot with two flexible joints was also implemented, where the moving speed reached 22 mm/s and the feasibility of the proposed flexible joint applied to a soft robot was demonstrated.

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Design of a Multi-Arm Robot for Mandible Reconstruction Surgery

2014 ◽  
Vol 654 ◽  
pp. 187-190 ◽  
Author(s):  
Hong Hua Zhao ◽  
Jian Ying Tian ◽  
Dong Song Li ◽  
Chang Sheng Ai
Keyword(s):  
Mechanical Design ◽  
The Novel ◽  
Robot System ◽  
Mandible Reconstruction ◽  
3D Navigation ◽  
Reconstruction Surgery ◽  
And Control ◽  
Robotic Surgical System ◽  
Surgical System ◽  
Poor Stability

Clinical treatment for mandible defects is Mandible Reconstruction Surgery (MRS) including bone grafts, distraction osteogenesis and bone tissue engineering, however, MRS is operated by doctors without 3D navigation at present which leads to lots of disadvantages such as bad operational control, low positioning accuracy and poor stability. Therefore, a robotic surgical system was designed to assist surgeons on manipulating. For this study, the robot system was given in brief, then mechanical design and control system of the novel three-arm robot.And experiment results in this study show that the robot works stably and accurately. The development of this medical robot system contributes to the promotion and popularization of the MRS in clinics.

Determination of Critical Crack Size Utilizing a Fracture Mechanics Test in Equipment Under Fatigue

2009 ◽  
Author(s):  
Irene Garcia Garcia ◽  
Radoslav Stefanovic
Keyword(s):  
Heat Treatment ◽  
Fracture Mechanics ◽  
Crack Size ◽  
Operational Experience ◽  
Element Analysis ◽  
Critical Crack ◽  
Circumferential Welds ◽  
Fea Model ◽  
Critical Crack Size

Equipment that is exposed to severe operational pressure and thermal cycling, like coke drums, usually suffer fatigue. As a result, equipment of this sort develop defects such as cracking in the circumferential welds. Operating companies are faced with the challenges of deciding what is the best way to prevent these defects, as well as determining how long they could operate if a defect is discovered. This paper discusses a methodology for fracture mechanics testing of coke drum welds, and calculations of the critical crack size. Representative samples are taken from production materials, and are welded employing production welding procedures. The material of construction is 1.25Cr-0.5Mo low alloy steel conforming to ASME SA-387 Gr 11 Class 2 in the normalized and tempered condition (N&T). Samples from three welding procedures (WPS) are tested: one for production, one for a repair with heat treatment, and one for repair without heat treatment. The position and orientation of test specimen are chosen based on previous surveys and operational experience on similar vessels that exhibited cracks during service. Fracture mechanics toughness testing is performed. Crack finite element analysis (FEA) model is used to determine the path-independed JI-integral driving force. Methodology for the determination of critical crack size is developed.

Electrothermal Characterization of Doped-Si Heated Microcantilevers Under Periodic Heating Operation

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Sina Hamian ◽  
Andrew M. Gauffreau ◽  
Timothy Walsh ◽  
Jungchul Lee ◽  
Keunhan Park
Keyword(s):  
Microelectromechanical Systems ◽  
Transfer Functions ◽  
Design Parameters ◽  
Periodic Heating ◽  
Element Analysis ◽  
Full Spectrum ◽  
Frequency Dependent ◽  
Thermal Transfer ◽  
Fea Model

This paper reports the frequency-dependent electrothermal behaviors of a freestanding doped-silicon heated microcantilever probe operating under periodic (ac) Joule heating. We conducted a frequency-domain finite-element analysis (FEA) and compared the steady periodic solution with 3ω experiment results. The computed thermal transfer function of the cantilever accurately predicts the ac electrothermal behaviors over a full spectrum of operational frequencies, which could not be accomplished with the 1D approximation. In addition, the thermal transfer functions of the cantilever in vacuum and in air were compared, through which the frequency-dependent heat transfer coefficient of the air was quantified. With the developed FEA model, design parameters of the cantilever (i.e., the size and the constriction width of the cantilever heater) and their effects on the ac electrothermal behaviors were carefully investigated. Although this work focused on doped-Si heated microcantilever probes, the developed FEA model can be applied for the ac electrothermal analysis of general microelectromechanical systems.

Patient-Specific 3D Finite-Element Analysis of Miniscrew Implants During Orthodontic Treatment

2009 ◽  
Author(s):  
Hussein H. Ammar ◽  
Victor H. Mucino ◽  
Peter Ngan ◽  
Richard J. Crout ◽  
Osama M. Mukdadi
Keyword(s):  
Finite Element ◽  
Orthodontic Treatment ◽  
3D Model ◽  
Patient Specific ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Miniscrew Implants ◽  
Operative Planning ◽  
Miniscrew Implant ◽  
Maximum Stresses

Miniscrew implants have seen increasing clinical use as orthodontic anchorage devices with demonstrated stability. The focus of this study is to develop and simulate operative factors, such as load magnitudes and anchor locations to achieve desired motions in a patient-specific 3D model undergoing orthodontic treatment with miniscrew implant anchorage. A CT scan of a patient skull was imported into Mimics software (Materialise, 12.1). Segmentation operations were performed on the images to isolate the mandible, filter out noise, then reconstruct a smooth 3D model. A model of the left canine was reconstructed with the PDL modeled as a thin solid layer. A miniscrew was modeled with dimensions based on a clinical implant (BMK OAS-T1207) then inserted into the posterior mandible. All components were volumetrically meshed and optimized in Mimics software. Elements comprising the mandible bone and teeth were assigned a material based on their gray value ranges in HU from the original scan, and meshes were exported into ANSYS software. All materials were defined as linear and isotropic. A nonlinear PDL was also defined for comparison. For transverse forces applied on the miniscrew, maximum stresses increased linearly with loading and appeared at the neck or first thread and in the cortical bone. A distal tipping force was applied on the canine, and maximum stresses appeared in the tooth at the crown and apex and in the bone at the compression surface. Under maximum loading, stresses in bone were sufficient for resorption. The nonlinear PDL exhibited lower stresses and deflections than the linear model due to increasing stiffness. Numerous stress concentrations were seen in all models. Results of this study demonstrate the potential of patient-specific 3D reconstruction from CT scans and finite-element simulation as a versatile and effective pre-operative planning tool for orthodontists.

Soil Modeling Using FEA and SPH Techniques for a Tire-Soil Interaction

2011 ◽  
Author(s):  
Moustafa El-Gindy ◽  
Ryan Lescoe ◽  
Fredrik O¨ijer ◽  
Inge Johansson ◽  
Mukesh Trivedi
Keyword(s):  
Surface Pressure ◽  
Particle Density ◽  
Plastic Material ◽  
Material Model ◽  
Shear Displacement ◽  
Physical Models ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Vertical Loading ◽  
Fea Model

In recent years, the advancement of computerized modeling has allowed for the creation of extensive pneumatic tire models. These models have been used to determine many tire properties and tire-road interaction parameters which are either prohibitively expensive or unavailable with physical models. More recently, computerized modeling has been used to explore tire-soil interactions. The new parameters created by these interactions were defined for these models, but accurate soil constitutive equations were lacking. With the previous models, the soil was simulated using Finite Element Analysis (FEA). However, the meshless modeling method of Smooth Particle Hydrodynamics (SPH) may be a viable approach to more accurately simulating large soil deformations and complex tire-soil interactions. With both the FEA and SPH soils modeled as elastic-plastic solids, simplified soil tests are conducted. First, pressure-sinkage tests are used to explore the differences in the two soil-modeling methods. From these tests, it is found that the FEA model supports a surface pressure via the tensile forces created by the stretching of the surface elements. Conversely, for the SPH model, the surface pressure is supported via the compressive forces created by the compacting of particles. Next, shear-displacement tests are conducted with the SPH soil (as this test cannot easily be performed with an FEA soil model). These shear tests show that the SPH soil behaves more like clay in initial shearing and more like sand by exhibiting increased shearing due to vertical loading. While both the pressure-sinkage and shear-displacement tests still show that a larger particle density is unnecessary for SPH soil modeling, the shear-displacement tests indicate that an elastic-plastic material model may not be the best choice.

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