scholarly journals Numerical Analysis and Strength Evaluation of an Exposed River Crossing Pipeline with Casing Under Flood Load

2018 ◽  
Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Mengying Xia ◽  
Yanfei Chen ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Flow Velocity ◽  
Yield Criterion ◽  
Element Model ◽  
Failure Criteria ◽  
General Purpose ◽  
Von Mises Stress ◽  
Critical Flow Velocity ◽  
Pipe Segment ◽  
Von Mises

Pipelines in service always experience complicated loadings induced by operational and environmental conditions. Flood is one of the common natural hazard threats for buried steel pipelines. One exposed river crossing X70 gas pipeline induced by flood erosion was used as a prototype for this study. A mechanical model was established considering the field loading conditions. Morison equations were adopted to calculate distributional hydrodynamic loads on spanning pipe caused by flood flow. Nonlinear soil constraint on pipe was considered using discrete nonlinear soil springs. An explicit solution of bending stiffness for pipe segment with casing was derived and applied to the numerical model. The von Mises yield criterion was used as failure criteria of the X70 pipe. Stress behavior of the pipe were analyzed by a rigorous finite element model established by the general-purpose Finite-Element package ABAQUS, with 3D pipe elements and pipe-soil interaction elements simulating pipe and soil constraints on pipe, respectively. Results show that, the pipe is safe at present, as the maximum von Mises stress in pipe with the field parameters is 185.57 MPa. The critical flow velocity of the pipe is 5.8 m/s with the present spanning length. The critical spanning length of the pipe is 467 m with the present flow velocity. The failure pipe sections locate at the connection point of the bare pipe and the pipe with casing or the supporting point of the bare pipe on riverbed.

scholarly journals A Finite Element Study of the Residual Stress and Deformation in Hemispherical Contacts

2005 ◽  
Vol 127 (3) ◽  
pp. 484-493 ◽  
Author(s):  
Robert Jackson ◽  
Itti Chusoipin ◽  
Itzhak Green
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Yield Criterion ◽  
Contact Region ◽  
Element Model ◽  
Von Mises Stress ◽  
Contact Radius ◽  
Perfectly Plastic ◽  
Von Mises

This work presents a finite element model (FEM) of the residual stresses and strains that are formed after an elastoplastic hemispherical contact is unloaded. The material is modeled as elastic perfectly plastic and follows the von Mises yield criterion. The FEM produces contours for the normalized axial and radial displacements as functions of the removed interference depth and location on the surface of the hemisphere. Contour plots of the von Mises stress and other stress components are also presented to show the formation of the residual stress distribution with increasing plastic deformation. This work shows that high residual von Mises stresses appear in the material pileup near the edge of the contact area after complete unloading. Values are defined for the minimum normalized interference, that when removed, results in plastic residual stresses. This work also defines an interference at which the maximum residual stress transitions from a location below the contact region and along the axis of symmetry to one near to the surface at the edge of the contact radius (within the pileup).

An Improved Control Arm Design for a Commercial Vehicle

2021 ◽  
Author(s):  
Sinan Yıldırım ◽  
Ufuk Çoban ◽  
Mehmet Çevik
Keyword(s):  
Finite Element ◽  
Cost Effective ◽  
Element Model ◽  
Tensile Tests ◽  
The Body ◽  
Von Mises Stress ◽  
Driving Safety ◽  
Design Development ◽  
Element Analysis ◽  
Von Mises

Suspension linkages are one of the fundamental structural elements in each vehicle since they connect the wheel carriers i.e. axles to the body of the vehicle. Moreover, the characteristics of suspension linkages within a suspension system can directly affect driving safety, comfort and economics. Beyond these, all these design criteria are bounded to the package space of the vehicle. In last decades, suspension linkages have been focused on in terms of design development and cost reduction. In this study, a control arm of a diesel public bus was taken into account in order to get the most cost-effective design while improving the strength within specified boundary conditions. Due to the change of the supplier, the control arm of a rigid axle was redesigned to find an economical and more durable solution. The new design was analyzed first by the finite element analysis software Ansys and the finite element model of the control arm was validated by physical tensile tests. The outputs of the study demonstrate that the new design geometry reduces the maximum Von Mises stress 15% while being within the elastic region of the material in use and having found an economical solution in terms of supplier’s criteria.

Finite Element Analysis of Gold Bonding under Different Loading Conditions

2014 ◽  
Vol 607 ◽  
pp. 713-716
Author(s):  
Wen Liang Tang ◽  
Chun Yue Huang ◽  
Tian Ming Li ◽  
Ying Liang ◽  
Guo Ji Xiong ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Simulation Software ◽  
Bonding Time ◽  
Von Mises Stress ◽  
Bonding Pressure ◽  
Element Analysis ◽  
Von Mises ◽  
Three Dimensional Finite Element

In this paper, ANSYS-LSDYNA simulation software is used to build the three-dimensional finite element model of the ball bond and to get the Von Mises stress. The change of stress about the bump is researched which base on the model in different bonding pressure, bonding power and bonding time. The result show that: The stress increase with bonding pressure increase within a certain bonding pressure range, and then the stress will maintain a table number, however, the stress will continue to increase when the bonding pressure reach a certain value; increasing the bonding power, the area of lager stress will grow; prolonging the bonding time, the stress of the pad will increase with time, but when time increase to a certain value, the stress of the pad will not increase over time.

Application of Algorithms for Percentiles of von Mises Stress From Combined Random Vibration and Static Loadings

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Patrick A. Tibbits
Keyword(s):  
Finite Element ◽  
Standard Deviation ◽  
Random Vibration ◽  
Yield Criterion ◽  
Stress Component ◽  
Linear Structure ◽  
Von Mises Stress ◽  
Test Model ◽  
Von Mises ◽  
Gaussian Time

Gaussian time-varying loading induces Gaussian components of the stress tensor in a linear structure, where the loading is assumed stationary. For any stress component, finite element spectrum analysis obtains the standard deviation, and any percentile can be calculated as a multiple of the standard deviation. However, a yield criterion requires a percentile of von Mises stress. The distribution of von Mises stress arising from random vibration loading stymies closed-form characterization, but several algorithms estimate its percentiles. One algorithm treats combined random vibration and static loadings. This paper improves computational efficiency for special plane stress cases, e.g., combining finite element spectrum and static analyses of piping models. All the algorithms are applied to a simple test model. Results match Monte Carlo simulation. Computational efficiencies are evaluated and compared.

Chest Deflection vs. Chest Acceleration as Injury Indicator in Front Impact Simulations Using Full Human Body Finite Element Model

2009 ◽  
Author(s):  
Raed E. El-Jawahri ◽  
Jesse S. Ruan ◽  
Stephen W. Rouhana ◽  
Saeed D. Barbat
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Human Body ◽  
Element Model ◽  
Von Mises Stress ◽  
Head Acceleration ◽  
Blunt Impact ◽  
Von Mises ◽  
Impact Simulations

The Ford Motor Company Human Body Finite Element Model (FHBM) was validated against rib dynamic tension and 3-point bending tests. The stress-strain and moment-strain data from the tension and bending simulations respectively were compared with human rib specimen test data. The model used represented a 50th percentile adult male. It was used to compare chest deflection and chest acceleration as thoracic injury indicator in blunt impact and belted occupants in front sled impact simulations. A 150 mm diameter of 23.4 kg impactor was used in the blunt impact simulations with impact speeds of 2, 4, and 8 m/s. In the Front sled impact simulations, single-step acceleration pulses with peaks of 10, 20, and 30 g were used. The occupants were restrained by 3-point belt system, however neither pretensioner nor shoulder belt force limiter were used. The external force, head acceleration, chest deflection, chest acceleration, and the maximum values of Von Mises stress and plastic strain were the model outputs. The results showed that the external contact force, head acceleration, chest deflection, and chest acceleration in the blunt impact simulations varied between 1.5–7 kN, 5–28 g, 18–80 mm, and 8–40 g respectively. The same responses varied between 7–24 kN, 13–40 g, 15–50 mm, and 16–46 g respectively in the front sled impact simulations. The maximum Von Mises stress and plastic strain were 50–127 MPa, and 0.04–2% respectively in the blunt impact simulations and 72–134 MPa, and 0.13–3% respectively in the sled impact simulations.

scholarly journals Assessment of stress changes in dentoalveolar and skeletal structures of the mandible with the miniplate anchored Forsus: A three-dimensional finite element stress analysis study

2017 ◽  
Vol 7 ◽  
pp. 87-93
Author(s):  
Harshal Ashok Patil ◽  
Pawankumar Dnyandeo Tekale ◽  
Veerendra V. Kerudi ◽  
Jitendra S. Sharan ◽  
Ratnadip Arunrao Lohakpure ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Functional Appliance ◽  
3D Finite Element ◽  
Fixed Functional Appliance ◽  
Finite Element Stress Analysis ◽  
Von Mises

ObjectiveThe study conducted to assess the effects of a fixed functional appliance (Forsus Fatigue Resistant Device; 3M Unitek, Monrovia, CA, USA) on the mandible with three-dimensional (3D) finite element stress analysis.Materials and MethodsA 3D finite element model of mandible with miniplate at mandibular symphysis was prepared using SolidEdge software along with the plate geometry. The changes were deliberated with the finite element method, in the form of highest von Mises stress and maximum principal stress regions.ResultsMore areas of stress were seen in the model of the mandible at cortical bone in canine region at bone and miniplate interface.ConclusionsThis fixed functional appliance studied by finite element model analysis caused more von Mises stress and principal stress in both the cortical bone and the condylar region.

Finite Element Analysis of Screw-Plate Systems for Fixation of Parasymphyseal Fractures of the Mandible

2007 ◽  
Vol 23 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Scott T. Lovald ◽  
Tariq Khraishi ◽  
John Wood ◽  
Jon Wagner ◽  
Bret Baack ◽  
...  
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Point Of View ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Fracture Region ◽  
Modeling Practices ◽  
Orthotropic Properties ◽  
Von Mises ◽  
Early Healing

AbstractFinite Element Modeling was used to compare the efficacy of common screw-plate configurations used for fixation of parasymphyseal fractures of the mandible. Measures of Von Mises stress on the screw bone interface, as well as principal strain in the reduced fracture region, were used in this comparison. This study also explored differences between orthotropic and isotropic modeling practices and compared the effect of mastication forces on both the fractured and intact halves of the mandible. The results of this analysis showed no major differences between configurations from a mechanistic point of view. This suggests that the use of any of the studied screw-plate configurations will not increase chances for post-operative complications. Furthermore, little difference is seen between analyses with either orthotropic or isotropic material properties. The inclusion of orthotropic properties can thus be avoided in future studies with similar boundary and plating conditions. Mastication ipsilateral to the fracture increases Von Mises stress 2 to 4 times, and should be avoided during early healing periods. These recommendations only apply to patients whose fractures mimic the finite-element model.

Three-Dimensional Thermo-Mechanical Finite Element Simulation for Casting Ladle Structure under Thermal Loadings

2008 ◽  
Vol 575-578 ◽  
pp. 1-6
Author(s):  
Shou Ju Li ◽  
Ying Xi Liu ◽  
He Yu
Keyword(s):  
Finite Element ◽  
Shell Structure ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Element Model ◽  
Steel Shell ◽  
Casting Ladle ◽  
Lining Structure ◽  
Calculation Results ◽  
Von Mises

The finite element model of coupling the thermal field with structural analysis is proposed in order to analyze the thermo-stress of casting ladle structure. The thermal fields of casting ladle with refractory lining structure are computed according to the thermal properties of materials and boundary conditions. Numerical simulation shows that that computed outer temperatures of casting ladle agree with measured ones. The thermo-stress of casting ladle structure is simulated by taking thermal loadings as the loading conditions of the steel shell structure. Material behaviors were described by the Drucker–Prager plasticity model and Von Mises yield criterion. Calculation results of thermo-stress fields shows the outer shell structure is safety under the action of thermal loadings.

Evaluation of Biomechanical Health Degree of Peri-Implant Bone Through Finite Element Analysis: A First Approach

2018 ◽  
Vol 10 (09) ◽  
pp. 1850097 ◽  
Author(s):  
Junxiong Lin ◽  
Ge Zhang ◽  
Zhenyu Jiang ◽  
Liqun Tang ◽  
Keqian Lian
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Critical Role ◽  
Control Sample ◽  
Stress Shielding ◽  
Element Model ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Computer Tomography Scan ◽  
Von Mises

The biomechanical health degree of peri-implant bone plays a critical role during the service of implants. This paper presents a preliminary exploration of the quantitative evaluation of the biomechanical health degree for the bone tissues around dental implant through finite element method. The finite element model of a part of mandible with three molars is constructed based on computer tomography scan image as a control sample, which is supposed to represent a healthy state. The model of treated mandible is made by replacing the middle tooth in the healthy model with a commercial implant. A regional average strain energy density (RASED) is proposed as a more accurate index to describe the stress state of peri-implant bone tissues, compared with the widely used maximum equivalent von Mises stress. The simulation shows that the stress state in peri-implant bone, i.e., the distribution and level of stress, is highly dependent on the modulus of implant material. Among the implants made of materials with various moduli, including Ti, stainless steel, zirconia, porous Ti, dentin material and polyether-ether-ketone (PEEK), the ones with medium modulus (15–40[Formula: see text]GPa) are found to achieve relatively healthy stress states. This study provides an effective tool to assess the risk of overloading or stress shielding in peri-implant bone tissues. It demonstrates a great potential in the optimization of design, production and usage of implants.

Coupled Thermal Analysis on Carbide Anvil of Cubic Press

2014 ◽  
Vol 852 ◽  
pp. 629-633
Author(s):  
Xian Jun Zhou ◽  
Zhong Wen Xu ◽  
Ren Quan Chen ◽  
Shao Ping Li
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Shear Stress ◽  
Element Model ◽  
Heat Transfer Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Material Defects ◽  
Indirect Coupling ◽  
Von Mises

Based on finite element analysis software ANSYS, the 3D contact finite element model of carbide anvil, steel ring and cushion block were built to make heat transfer analysis, and the temperature field distribution was obtained. The indirect coupling thermal analysis of carbide anvil, steel ring and cushion block were made regarding as a whole, the Von Mises stress nephogram of them and the shear stress nephogram of carbide anvil were displayed. The stress nephogram revealed that it was liable to fracture on the edge of top surface under high pressure status, and it was also proven that the main reason of fracture was the yield of internal material defects under the action of shear stress.

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