Deformation Analysis of Fixturing for Workpiece with Complex Geometry

2005 ◽  
Vol 291-292 ◽  
pp. 631-636 ◽  
Author(s):  
Yan Wang ◽  
Xun Chen ◽  
Nabil Gindy
Keyword(s):  
Finite Element ◽  
Turbine Blade ◽  
Complex Geometry ◽  
Early Stage ◽  
Fe Analysis ◽  
Accurate Prediction ◽  
Deformation Analysis ◽  
Design Problems ◽  
Surface Error

Finite element (FE) analysis is very useful in the early stage of a fixture development in order to reduce or eliminate design problems. Accurate prediction of fixture-workpiece deformation requires an appropriate representation of the contact relationship between fixture elements and workpieces. The paper addresses the special features of the deformation analysis between complicatedly shaped components and fixture elements. The effectiveness and the scope of applicability of commonly used methods are analysed. The verified FE analysis is used to predict surface error arising from deformations, and to evaluate the deformation distributions from fixture elements and workpiece. Based on the FE analysis, the tolerance can be allocated to the fixture elements and the workpiece. The development of a turbine blade fixture is provided as case study.

scholarly journals MONITORING OF PROGRESSIVE DAMAGE IN BUILDINGS USING LASER SCAN DATA

2018 ◽  
Vol XLII-2 ◽  
pp. 923-929 ◽  
Author(s):  
I. Puente ◽  
R. Lindenbergh ◽  
A. Van Natijne ◽  
R. Esposito ◽  
R. Schipper
Keyword(s):  
Point Cloud ◽  
Early Stage ◽  
Principal Component ◽  
Point Clouds ◽  
Deformation Analysis ◽  
Main Concern ◽  
Specific Element ◽  
University Of Technology ◽  
Scan Data

Vulnerability of buildings to natural and man-induced hazards has become a main concern for our society. Ensuring their serviceability, safety and sustainability is of vital importance and the main reason for setting up monitoring systems to detect damages at an early stage. In this work, a method is presented for detecting changes from laser scan data, where no registration between different epochs is needed. To show the potential of the method, a case study of a laboratory test carried out at the Stevin laboratory of Delft University of Technology was selected. The case study was a quasi-static cyclic pushover test on a two-story high unreinforced masonry structure designed to simulate damage evolution caused by cyclic loading. During the various phases, we analysed the behaviour of the masonry walls by monitoring the deformation of each masonry unit. First a plane is fitted to the selected wall point cloud, consisting of one single terrestrial laser scan, using Principal Component Analysis (PCA). Second, the segmentation of individual elements is performed. Then deformations with respect to this plane model, for each epoch and specific element, are determined by computing their corresponding rotation and cloud-to-plane distances. The validation of the changes detected within this approach is done by comparison with traditional deformation analysis based on co-registered TLS point clouds between two or more epochs of building measurements. Initial results show that the sketched methodology is indeed able to detect changes at the mm level while avoiding 3D point cloud registration, which is a main issue in computer vision and remote sensing.

Structural Design and Finite Element Analysis of Composite Wind Turbine Blade

2012 ◽  
Vol 525-526 ◽  
pp. 225-228 ◽  
Author(s):  
Shi Fan Zhu ◽  
Ibrohim Rustamov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Structural Reliability ◽  
Complex Geometry ◽  
Wind Turbine Blade ◽  
Blade Design ◽  
Horizontal Axis Wind Turbine ◽  
Element Method

This paper presents structural studies of a medium scale composite wind turbine blade construction made of epoxy glass fiber for a 750kW rated power stall regulated horizontal axis wind turbine system. The complex geometry of the blade with a skin-spar foam sandwich structure was generated by utilizing commercial code ANSYS finite element package. Dimensions of twist, chord and thickness were developed by computer program. NREL S-series airfoils with different chord thickness are used along current blade cross-sections. The current design method uses blade element momentum (BEM) theory to complete satisfactory blade design and can be carried out using a spreadsheet, lift and drag curves for the chosen aerofoil. According to composite laminate theory and finite element method, optimal blade design was obtained. The focus is on the structural static strength of wind turbine blades loaded in flap-wise direction and methods for optimizing the blade cross-section to improve structural reliability. Moreover, the natural frequencies and modal shapes of the rotor blade were calculated for defining dynamic characteristics. Structural analysis was performed by using the finite element method in order to evaluate and confirm the blade to be sound and stable under various load conditions.

scholarly journals Finite Element Modeling and Stress Analysis of a Six-Splitting Mid-Phase Jumper

2020 ◽  
Vol 10 (2) ◽  
pp. 644 ◽  
Author(s):  
Ma ◽  
Li ◽  
Han ◽  
He ◽  
Xiao
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Complex Geometry ◽  
Element Model ◽  
Wind Load ◽  
Modeling Method ◽  
Local Model ◽  
Deformation Analysis ◽  
Actual Structure ◽  
Bending Deformation

In this study, a finite element, fully three-dimensional solid modeling method was used to study the mechanical response of a steel-cored aluminum strand (ACSR) with a mid-phase jumper under wind load. A whole model (simplifying an ACSR into a solid cylinder) and a local model (modeling according to the actual structure of an ACSR) of the mid-phase jumper were established. First, the movement of the mid-phase jumper of the tension tower under wind load was studied based on the whole finite element model, and the equivalent Young’s modulus of the whole model was adjusted based on the local model. The results of the whole model were then imported into the local model and the stress distribution of each strand of the ACSR was analyzed in detail to provide guidance for the treatment measures. Therefore, the whole model and the local model complemented each other, which could reduce the number of model operations and ensure the accuracy of the results. Through the follow-up test to verify the results of the finite element simulation and the comparison of the simulation and fatigue test results, the causes of the broken strand of the ACSR were discussed. Although this modeling method was applied to the stress and deformation analysis of a mid-phase jumper in this study, it can be used to study the bending deformation of rope structures with a complex geometry and the main bending deformation. In addition, the effect of the friction coefficient on the bending of the mid-phase jumper was studied.

scholarly journals NUMERICAL METHODS FOR THE SIMULATION OF DEFORMATIONS AND STRESSES IN TURBINE BLADE FIR-TREE CONNECTIONS

2019 ◽  
Vol 17 (1) ◽  
pp. 1 ◽  
Author(s):  
Justus Benad
Keyword(s):  
Finite Element ◽  
Boundary Element Method ◽  
Numerical Methods ◽  
Turbine Blade ◽  
Complex Geometry ◽  
Great Success ◽  
Numerical Techniques ◽  
Application Range ◽  
Method Of Dimensionality Reduction ◽  
Computationally Expensive

In this work, different numerical methods for simulating deformations and stresses in turbine blade fir-tree connections are examined. The main focus is on the Method of Dimensionality Reduction (MDR) and the Boundary Element Method (BEM). Generally, the fir-tree connections require a computationally expensive finite element setup. Their complex geometry exceeds the limitations of the faster numerical techniques which are used with great success within the framework of the half-space approximation. Ways of extending the application range of the MDR and the BEM to the particular problem of highly undulating surfaces of the fir-tree connection are shown and discussed.

A novel methodology to automatically include general track flexibility in railway vehicle dynamic analyses

2020 ◽  
pp. 095440972094542
Author(s):  
JN Costa ◽  
P Antunes ◽  
H Magalhães ◽  
J Pombo ◽  
J Ambrósio
Keyword(s):  
Finite Element ◽  
Vehicle Dynamics ◽  
Complex Geometry ◽  
Rolling Stock ◽  
Railway Vehicle ◽  
Moving Loads ◽  
Element Mesh ◽  
Complete Representation ◽  
Parametric Description

The interaction between the rolling stock and the infrastructure plays a crucial role in railway vehicle dynamics. The standard approach consists of using a multibody formulation to model the railway vehicles running on simplified tracks. The track model can be rigid, if it comprises only a geometric description of the rail; semi-rigid, if it considers an elastic foundation underneath the rail; or a moving track model, if it comprises a track section underneath each wheelset traveling with the same speed of the vehicle. Despite their computational inexpensiveness, these approaches do not provide a complete representation of track flexibility and disregard coupling effects with the vehicle and among the track components. This work proposes a methodology to automatically generate finite element models of railway tracks comprising its relevant flexible components, i.e., rails, pads, fastening systems, sleepers, and ballast or slab. The finite element mesh is generated based on a parametric description of the track that allows an accurate description of its geometry, including curvature, cross-level, grade, and irregularities. The methodology is demonstrated with a case study in which a track with a complex geometry is loaded with two different approaches. The first approach prescribes moving loads, which is a typical approach used to design or analyze the infrastructure. The second approach applies loads retrieved from the dynamic analysis of a complete vehicle. The results show the benefits of this method and reveal that prescribed loading underestimates the forces resulting from the vehicle dynamics, which is an important issue on curved sections.

A Proof for the Possibility of Ce-Oxide from CMP Residuals in Si-Wafers by Analytical TEM

2012 ◽  
Author(s):  
Wayne Zhao ◽  
Liem Do Thanh ◽  
Michael Gribelyuk ◽  
Mary-Ann Zaitz ◽  
Wing Lai
Keyword(s):  
Technology Development ◽  
Early Stage ◽  
Chemical Mechanical Planarization ◽  
Particle Cluster ◽  
Limited Region ◽  
Physical Evidence ◽  
Analytical Tem ◽  
Transmission Electron ◽  
Oxide Particles

Abstract Inclusion of cerium (Ce) oxide particles as an abrasive into chemical mechanical planarization (CMP) slurries has become popular for wafer fabs below the 45nm technology node due to better polishing quality and improved CMP selectivity. Transmission electron microscopy (TEM) has difficulties finding and identifying Ce-oxide residuals due to the limited region of analysis unless dedicated efforts to search for them are employed. This article presents a case study that proved the concept in which physical evidence of Ce-rich particles was directly identified by analytical TEM during a CMP tool qualification in the early stage of 20nm node technology development. This justifies the need to setup in-fab monitoring for trace amounts of CMP residuals in Si-based wafer foundries. The fact that Cr resided right above the Ce-O particle cluster, further proved that the Ce-O particles were from the wafer and not introduced during the sample preparation.

Numerical implementation of finite-element method of control volume using irregular mesh

2010 ◽  
Vol 7 ◽  
pp. 98-108
Author(s):  
Yu.A. Gafarova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Delaunay Triangulation ◽  
Complex Geometry ◽  
Control Volume ◽  
Test Case ◽  
The Finite Element Method ◽  
Irregular Mesh ◽  
Discrete Analogues ◽  
Element Method

To solve problems with complex geometry it is considered the possibility of application of irregular mesh and the use of various numerical methods using them. Discrete analogues of the Beltrami-Mitchell equations are obtained by the control volume method using the rectangular grid and the finite element method of control volume using the Delaunay triangulation. The efficiency of using the Delaunay triangulation, Voronoi diagrams and the finite element method of control volume in a test case is demonstrated.

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