Linear Static, Real-Time Finite Element Computations Based on Element Masks

2011 ◽  
Author(s):  
Holger Graf ◽  
Andre´ Stork
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Boundary Conditions ◽  
Real Time ◽  
Stiffness Matrix ◽  
New Method ◽  
Stress Distributions ◽  
Post Processing ◽  
Time Performance ◽  
Computational Overhead

This paper presents a new method for the manipulation of a given CAE domain in view of VR based explorations that enables engineers to interactively inspect and analyze a linear static domain. The interactions can ideally be performed in real-time in order to provide an intuitive impression of the changes to the underlying volumetric domain. We take the approach of element masking, i.e. the blending out of computations resulting from computational overhead for inner nodes, based on the inversion of the stiffness matrix. This allows us to optimize the re-simulation loop and to achieve real-time performance for strain and stress distributions with immediate visualization feedback caused by interactively changing boundary conditions. The novelty of the presented approach is a direct coupling of view dependent simulations and its close linkage to post-processing tasks. This allows engineers to also inspect the changes of the stress field inside of the volume during, e.g. cross sectioning.

Real Time Techniques for Nonlinear Tissue Deformation in Surgical Simulation

2007 ◽  
Author(s):  
Suvranu De ◽  
Yi-Je Lim
Keyword(s):  
Finite Element ◽  
Real Time ◽  
Surgical Simulation ◽  
Computational Technique ◽  
Finite Element Models ◽  
Geometrically Nonlinear ◽  
Time Performance ◽  
Surgical Tool ◽  
Surgical Simulations ◽  
Tissue Deformations

The requirement of real time performance, crucial to multimodal surgical simulations, imposes severe demands in terms of computational efficiency. A physics-based meshfree computational technique known as the Point-Associated Finite Field (PAFF) approach has been developed to circumvent many outstanding problems associated with traditional mesh-based computational schemes and has been applied in this paper to the modeling of geometrically nonlinear tissue deformations. The technique is based on a novel combination of multiresolution approach coupled with a fast reanalysis scheme in which the response predicted by an underlying linear PAFF model is enhanced in the local neighborhood of the surgical tool-tip by a nonlinear model. We present performance comparisons of PAFF with traditional finite element models.

scholarly journals Ship Target Detection Based on Improved YOLO Network

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hong Huang ◽  
Dechao Sun ◽  
Renfang Wang ◽  
Chun Zhu ◽  
Bangquan Liu
Keyword(s):  
Real Time ◽  
Target Detection ◽  
Network Structure ◽  
Small Volume ◽  
Recall Rate ◽  
New Method ◽  
Convolution Operation ◽  
Time Performance ◽  
Guided Filtering ◽  
Bounding Boxes

Ship target detection is an important guarantee for the safe passage of ships on the river. However, the ship image in the river is difficult to recognize due to the factors such as clouds, buildings on the bank, and small volume. In order to improve the accuracy of ship target detection and the robustness of the system, we improve YOLOv3 network and present a new method, called Ship-YOLOv3. Firstly, we preprocess the inputting image through guided filtering and gray enhancement. Secondly, we use k-means++ clustering on the dimensions of bounding boxes to get good priors for our model. Then, we change the YOLOv3 network structure by reducing part of convolution operation and adding the jump join mechanism to decrease feature redundancy. Finally, we load the weight of PASCAL VOC dataset into the model and train it on the ship dataset. The experiment shows that the proposed method can accelerate the convergence speed of the network, compared with the existing YOLO algorithm. On the premise of ensuring real-time performance, the precision of ship identification is improved by 12.5%, and the recall rate is increased by 11.5%.

A New Method of Stress Linearization for Design by Analysis in Pressure Vessel Design

2014 ◽  
Vol 598 ◽  
pp. 194-197
Author(s):  
Hong Jun Li ◽  
Qiang Ding ◽  
Xun Huang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
New Method ◽  
Stress Distributions ◽  
Bending Stress ◽  
Element Analysis ◽  
Stress Tensors ◽  
Section Viii ◽  
Division 2

Stress linearization is used to define constant and linear through-thickness FEA (Finite Element Analysis) stress distributions that are used in place of membrane and membrane plus bending stress distributions in pressure vessel Design by Analysis. In this paper, stress linearization procedures are reviewed with reference to the ASME Boiler & Pressure Vessel Code Section VIII Division 2 and EN13445. The basis of the linearization procedure is stated and a new method of stress linearization considering selected stress tensors for linearization is proposed.

A New Method for High Speed CAN Protocol Conversion Circuit

2014 ◽  
Vol 596 ◽  
pp. 873-876
Author(s):  
Qi Li ◽  
Yan Fei Liu ◽  
Da Cheng Luo ◽  
Jing Jing Yang
Keyword(s):  
Real Time ◽  
High Speed ◽  
Large Scale ◽  
Can Bus ◽  
New Method ◽  
Time Performance ◽  
Test Instrument ◽  
Protocol Conversion

Due to high correspondence speed, great real-time performance and good expansibility, CAN bus has been used widely in aerospace, large-scale equipments and other fields these years .This paper introduces a kind of CAN Bus Test Instrument based on PXI bus and FPGA, which is used to test and monitor the CAN bus equipment. The result of test shows that this kind of test instrument has great advantages in reliability, stability and extensibility.

Determination of Parameters in Compound Fill Sphere Model for Haptic Interaction

2012 ◽  
Vol 190-191 ◽  
pp. 277-283
Author(s):  
Yong Liu ◽  
Yan Chao Zhang ◽  
Wu Sheng Chou
Keyword(s):  
Finite Element ◽  
Real Time ◽  
Stiffness Matrix ◽  
Mass Matrix ◽  
Deformable Body ◽  
Element Model ◽  
Sphere Model ◽  
Haptic Interaction ◽  
Determination Of Parameters ◽  
First Time

The compound Fill Sphere Model (cFSM), which is an extension of common Fill Sphere Model, is widely used in real-time haptic interaction with deformable body. Comparing with finite element based model, the simplicity and efficiency are advantages of cFSM. However, determining implicit parameters of cFSM is a difficult task since a vivid deformation should be attained during haptic interaction. In this paper, to improve the simulation precision, parameter matrices of the cFSM are identified through an analytical method for the first time to our best knowledge. After deriving parameter matrices by linearization, the stiffness matrix, damp matrix and mass matrix of the cFSM are obtained by minimizing errors between stiffness matrix of the Finite Element Model (FEM). In order to evaluate the performance of derived parameters, comparative experiment has been conducted between the cFSM and FEM. Additionally, based on the derived parameters, a real-time haptic interactive scenario is constructed to validate the performance of deformation simulation.

Influence of interlayer dwell time on stress field of thin-walled components in WAAM via numerical simulation and experimental tests

2019 ◽  
Vol 25 (8) ◽  
pp. 1433-1441 ◽  
Author(s):  
Rong Li ◽  
Jun Xiong
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Ambient Temperature ◽  
Dwell Time ◽  
Stress Distributions ◽  
Widespread Application ◽  
Content Type ◽  
Longitudinal Residual Stress ◽  
Thin Walled

Purpose This paper aims to study the residual stress of deposited components which is a main issue to impede the widespread application of wire and arc additive manufacturing (WAAM). The interlayer dwell time is believed to have an effect on residual stress distributions in WAAM due to variance in heat dissipation condition. A coupled thermomechanical finite element model was established to evaluate the role of dwell time in between layers on the mechanical behavior of thin-walled components in WAAM, mainly involving thermal stress evolutions and residual stress distributions of the component and substrate. Design/methodology/approach Four interlayer dwell times including 0, 120 and 300 s and cooling to ambient temperature were selected in finite element modeling, and corresponding experiments were conducted to verify the reliability of the model. Findings The results show that with the interlayer dwell time, the stress cycling curves become more uniform and the interlayer stress-releasing effect is weakened. The residual stress levels on the substrate decrease with the increasing interlayer dwell time. In the outside surface of the component, the distributions of axial and longitudinal residual stress along the deposition path are the smoothest when the interlayer dwell time is cooling to ambient temperature. In the inside surface, a longer interlayer dwell time leads to an obvious decrease in the longitudinal and axial residual stress along the deposition path. Originality/value The comprehensive study of how the interlayer dwell time influences stress field of components is helpful to improve the deposition defects generated by WAAM.

A New Method for Predicting the Opening Angle for Soft Tissues

2002 ◽  
Vol 124 (4) ◽  
pp. 347-354 ◽  
Author(s):  
Timothy J. Van Dyke ◽  
Anne Hoger
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Potential Energy ◽  
Biological Tissue ◽  
Soft Tissues ◽  
Element Model ◽  
New Method ◽  
Opening Angle ◽  
Residual Stress Field

The purpose of this paper is to present a simple new method for calculating the opening angle produced by a given residual stress field in a soft biological tissue. The method uses minimization of potential energy, and is therefore named the MPE method. The accuracy of the MPE method is evaluated by comparing the opening angle it predicts to results from a finite element model of the opening angle experiment. We show that the MPE method provides good predictions of the opening angle, and that it is significantly more accurate than two other methods previously used in the literature.

scholarly journals On Simplified 3D Finite Element Simulations of Three-Core Armored Power Cables

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3081 ◽  
Author(s):  
Juan del-Pino-López ◽  
Marius Hatlo ◽  
Pedro Cruz-Romero
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Computation Time ◽  
New Method ◽  
Minimum Length ◽  
International Electrotechnical Commission ◽  
Medium Voltage ◽  
Periodic Models ◽  
Measurements Errors ◽  
Computational Resources

This paper analyzes different ways to electromagnetically simulate three-core armored cables in 3D by means of the finite element method. Full periodic models, as lengthy as 36 m, are developed to evaluate the accuracy when simulating only a small portion of the cable, as commonly employed in the literature. The adequate length and boundary conditions for having the same accuracy of full periodic models are also studied. To achieve this aim, five medium voltage and high voltage armored cables are analyzed, obtaining the minimum length of the cable that may be simulated for having accurate results in shorter time and with less computational burden. This also results in the proposal of a new method comprising the advantages of short geometries and the applicability of periodic boundary conditions. Its accuracy is compared with experimental measurements and the International Electrotechnical Commission (IEC) standard for 145 kV and 245 kV cables. The results show a very good agreement between simulations and measurements (errors below 4%), obtaining a reduction in the computation time of about 90%. This new method brings a more effective tool for saving time and computational resources in cable design and the development of new analytical expressions for improving the IEC standard.

scholarly journals Modeling and Thermal-Mechanical Coupling Analysis of Piston in Car Engines

2020 ◽  
Vol 45 (1) ◽  
pp. 83-92
Author(s):  
Feifei Zhao
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Stress Distribution ◽  
Stress Field ◽  
Boundary Conditions ◽  
Thermal Load ◽  
Mechanical Load ◽  
Field Analysis ◽  
Coupling Analysis ◽  
Mechanical Coupling

In this paper, finite-element analysis (FEA) is carried out on the temperature field and stress field of automobile engine piston, as well as the thermal-mechanical load coupling stress field. Through the analysis, the authors grasped the thermal load and combined stress distribution of the piston, and thus optimized the piston design to improve its operational reliability. Specifically, a 1/4 solid model of the piston was constructed in the three-dimensional (3D) computer-aided design (CAD) software Pro/ENGINEER, and then converted into a finite-element model in Pro/Mechanica. Then, an alternating load was imposed on the piston model, and fatigue analysis was performed to identify the parts of the piston prone to fatigue failure, and judge whether the piston structure satisfies working requirements. Next, temperature field analysis was carried out on the piston model. The distribution of the steady-state temperature field as determined by applying temperatures and heat transfer coefficients as required by the boundary conditions of the third kind. Finally, the piston model was subject to thermal-mechanical coupling analysis. The stress and deformation distributions of the piston under the coupled stress field were ascertained under the boundary conditions of temperature field distribution and mechanical load. Through the above work, the authors obtained the basis for safety evaluation of piston, laying the foundation for further reducing the thermal load and optimizing the stress distribution of piston.

Study About Real-Time Finite Element Method Using CNN

2003 ◽  
Author(s):  
JingBo Gao ◽  
MinQiang Xu ◽  
RiXin Wang
Keyword(s):  
Neural Network ◽  
Finite Element Method ◽  
Finite Element ◽  
Temperature Field ◽  
Real Time ◽  
Stiffness Matrix ◽  
Arbitrary Shape ◽  
Cellular Neural Network ◽  
Thermal Stress Field ◽  
Element Method

The paper presents cellular neural network (CNN) for real-time finite element method, useful as calculating temperature field and thermal stress field for rotor of turbine and so on. The comparability between template of CNN and the stiffness matrix of finite element is analyzed, and the conception of finite element template (FMT) of CNN is discussed. The FMT can be suitable for finite element grid with arbitrary shape. In this paper, the FMT is simulated by temperature field of rotor of turbine, the result is right.

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