다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

PREFACE. ACKNOWLEDGMENTS. PROLOGUE. 1 INTRODUCTION. 1.1 Historical Perspective. 1.2 Diagnostic and Prognostic System Requirements. 1.3 Designing in Fault Diagnostic and Prognostic Systems. 1.4 Diagnostic and Prognostic Functional Layers. 1.5 Preface to Book Chapters. 1.6 References. 2 SYSTEMS APPROACH TO CBM/PHM. 2.1 Introduction. 2.2 Trade Studies. 2.3 Failure Modes and Effects Criticality Analysis (FMECA). 2.4 System CBM Test-Plan Design. 2.5 Performance Assessment. 2.6 CBM/PHM Impact on Maintenance and Operations: Case Studies. 2.7 CBM/PHM in Control and Contingency Management. 2.8 References. 3 SENSORS AND SENSING STRATEGIES. 3.1 Introduction. 3.2 Sensors. 3.3 Sensor Placement. 3.4 Wireless Sensor Networks. 3.5 Smart Sensors. 3.6 References. 4 SIGNAL PROCESSING AND DATABASE MANAGEMENT SYSTEMS. 4.1 Introduction. 4.2 Signal Processing in CBM/PHM. 4.3 Signal Preprocessing. 4.4 Signal Processing. 4.5 Vibration Monitoring and Data Analysis. 4.6 Real-Time Image Feature Extraction and Defect/Fault Classification. 4.7 The Virtual Sensor. 4.8 Fusion or Integration Technologies. 4.9 Usage-Pattern Tracking. 4.10 Database Management Methods. 4.11 References. 5 FAULT DIAGNOSIS. 5.1 Introduction. 5.2 The Diagnostic Framework. 5.3 Historical Data Diagnostic Methods. 5.4 Data-Driven Fault Classification and Decision Making. 5.5 Dynamic Systems Modeling. 5.6 Physical Model-Based Methods. 5.7 Model-Based Reasoning. 5.8 Case-Based Reasoning (CBR). 5.9 Other Methods for Fault Diagnosis. 5.10 A Diagnostic Framework for Electrical/Electronic Systems. 5.11 Case Study: Vibration-Based Fault Detection and Diagnosis for Engine Bearings. 5.12 References. 6 FAULT PROGNOSIS. 6.1 Introduction. 6.2 Model-Based Prognosis Techniques. 6.3 Probability-Based Prognosis Techniques. 6.4 Data-Driven Prediction Techniques. 6.5 Case Studies. 6.6 References. 7 FAULT DIAGNOSIS AND PROGNOSIS PERFORMANCE METRICS. 7.1 Introduction. 7.2 CBM/PHM Requirements Definition. 7.3 Feature-Evaluation Metrics. 7.4 Fault Diagnosis Performance Metrics. 7.5 Prognosis Performance Metrics. 7.6 Diagnosis and Prognosis Effectiveness Metrics. 7.7 Complexity/Cost-Benefit Analysis of CBM/PHM Systems. 7.8 References. 8 LOGISTICS: SUPPORT OF THE SYSTEM IN OPERATION. 8.1 Introduction. 8.2 Product-Support Architecture, Knowledge Base, and Methods for CBM. 8.3 Product Support without CBM. 8.4 Product Support with CBM. 8.5 Maintenance Scheduling Strategies. 8.6 A Simple Example. 8.7 References. APPENDIX. INDEX.

/pdf/intelligent-fault-diagnosis-and-prognosis-for-engineering-408f3g3g0d.pdf

Intelligent Fault Diagnosis and Prognosis for Engineering Systems

Boundary Value Problems in Physics and Engineering By Frank Chorlton. Pp. 250. (Van Nostrand: London, July 1969.) 70s

Boundary value problems

random data analysis and measurement procedures is available in our digital library an online access to it is set as public so you can get it instantly. Our book servers spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the random data analysis and measurement procedures is universally compatible with any devices to read.

Random Data Analysis And Measurement Procedures

As the power to weight ratio demand on rotordynamic systems increases, susceptibility to transverse fatigue cracking of the shaft increases as well. The ability to detect cracks in an early stage of progression is imperative for minimizing off-line repair time. A vibration monitoring system proposed prior is developed herein, employing the 2X harmonic response component of the rotor tilt as a signature indicating a transverse shaft crack. To effectively capture the 2X response, the crack model must include the local nature of the crack, the depth of the crack, and the stiffness asymmetry inducing the gravity-forced 2X harmonic response. The transfer matrix technique is well-suited to incorporate these crack attributes due to its modular nature. Two transfer matrix models are proposed to predict the 2X harmonic response. The first model applies local crack flexibility coefficients determined using the strain energy release rate, while the second incorporates the crack as a rectangular notch to emulate a manufactured crack used in the experiments. Analytic results are then compared to experimental measurement of the rotor tilt gleaned from an overhung rotor test rig originally designed to test seal face dynamics. The test rig is discussed, and experimental 2X harmonic amplitudes of the rotor tilt are provided for shafts containing manufactured cracks of depths between zero and 40 percent.Copyright © 2012 by ASME

Crack Detection in a Rotor Dynamic System by Vibration Monitoring: Analysis and Experimental Results

This work presents a combination of two dimensional (2D) and three dimensional (3D) finite element analysis (FEA) of structural and electrical contact between two nonconforming hemispheres at various vertical interferences. Items of particular interest include contact forces, current densities, and magnetic forces. The results are normalized to be applicable to micro and macro-scaled contact models. To test the validity of the analysis, the results are compared to another work focusing on contact between a hemisphere and rigid flat.Copyright © 2009 by ASME

Finite Element Analysis of Structural and Electromagnetic Effects on Asperity Contacts

: This report summarizes a three year study of noncontacting coned-face mechanical seal dynamics. Both small perturbation and full non-linear analyses are presented. An experimental technique to measure relevant dynamic properties of elastomeric secondary seals is described. The critical speed, for the dynamic stability threshold, and the critical rotor runout are presented. It is shown that the more simple to use small perturbation analysis gives very good results for most practical cases. This document includes information on the following form areas: 1) Stiffness and Damping Characteristics of Elastomer O-Rings Secondary Seals Subjected to Reciprocating Twist; 2) A Kinematic Model for Mechanical Seals with Antirotation Locks or Positive Drive Devices; 3) Stability Threshold and Steady-State Response of Noncontacting Coned-Face Seals; and 4) Nonlinear Dynamic Analysis of Noncontacting Coned-Face Mechanical Seals.

Mechanical Face Seal Dynamics.

\n This work derives analytically solutions to calculate the wear volume at the initiation of fretting motion, and its progression over the first few oscillation cycles. The Arcahrd-based model considers a deformable hemisphere that is contact with a deformable flat bock. The material pairs investigated are special alloys, the Inconel617/Incoloy800H and Inconel617/Inconel617. The analytical study begins with a unidirectional frictional sliding contact, where the local interfacial sliding distance and the nominal sliding distance at the initiation of gross slip are derived. The obtained analytical expressions for unidirectional sliding are then used to derive the corresponding wear volume for the initiation and progression of gross slip and the wear volume for a general fretting cycle under pure elastic conditions. These analytical derivations are all verified by finite element analyses (FEA). The FEA method and the analytical solutions render virtually identical results for both similar and dissimilar material pairs. The effects of plasticity on the wear volume under elastic-plastic conditions are also investigated. It is found that the fretting wear volumes obtained from the FEA simulations, which include plasticity, are close to those obtained from the analytical expressions for purely elastic regimes. All the results are presented in normalized forms, which can easily be generalized and applied to 3D fretting wear of other material pairs.

An Analytical Solution for the Initiation and Early Progression of Fretting Wear in Spherical Contacts

The transient temperature distribution in an infinitely long horizontal rotating cylinder which is partially filled by a viscous fluid is calculated. Thermal boundary and initial conditions are such that the fluid starts from a uniform temperature, and that the outer boundary (cylinder surface) is isothermal at a different temperature. Nondimensional analysis shows that the problem can be fully described by a properly defined Fourier modulus and a normalized bubble eccentricity.

Itzhak Green

Papers

Crack Detection in a Rotor Dynamic System by Vibration Monitoring: Analysis and Experimental Results

Finite Element Analysis of Structural and Electromagnetic Effects on Asperity Contacts

Mechanical Face Seal Dynamics.

An Analytical Solution for the Initiation and Early Progression of Fretting Wear in Spherical Contacts

Transient Temperature Distribution in Partially Filled Rotating Horizontal Cylinders