Development and Verification of Transfer Matrix Unbalance Response Procedure for Three-Level Rotor-Foundation Systems

1998 ◽  
Vol 120 (1) ◽  
pp. 240-251 ◽  
Author(s):  
N. F. Rieger ◽  
Shixiang Zhou
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
System Analysis ◽  
Computer Code ◽  
Level System ◽  
Matrix Methods ◽  
Stiffness Properties ◽  
Multi Level ◽  
Foundation Structure ◽  
Rotor Model

Details are presented of an analysis and computer code for the calculation of complex multi-span rotor-bearing-pedestal-foundation systems. This multi-level system analysis is based on the Prohl-Myklestad transfer matrix method. The rotor model used is similar to that given by Lund and Orcutt [1]. Eight-coefficient bearings are also used, to permit elliptical orbit rotor motions. The bearings are mounted in massive, damped flexible pedestals, which are themselves mounted upon a foundation structure with distributed mass and stiffness properties. The foundation in turn, is supported on a number of flexible-damped supports. Different foundation properties in the horizontal and vertical directions are included. The analysis is described in detail, along with the computer code, and the results obtained with it are compared with data published previously by other investigators. It is shown that transfer matrix methods can be successfully used for multi-level systems, and that the additional computational ejfort involved is moderate. Three applications of the code are described which validate various aspects of the analysis and the computer program.

Turbomachinery Dual Rotor-Bearing System Analysis

2002 ◽  
Author(s):  
Hsiao-Wei D. Chiang ◽  
Chih-Neng Hsu ◽  
Wes Jeng ◽  
Shun-Hsu Tu ◽  
Wei-Chen Li
Keyword(s):  
Finite Element ◽  
Transfer Matrix ◽  
Critical Speed ◽  
System Analysis ◽  
Design Parameters ◽  
Critical Speeds ◽  
Rotor Design ◽  
Rotor Bearing ◽  
Bearing Stiffness ◽  
Bearing System

It is very common for aircraft engines to have dual rotor or even triple rotor designs. Due to the complexity of having multiple rotor design, the transfer matrix methods have used in the past to deal with multiple rotor-bearing systems. However, due to transfer matrix method’s assumptions, sometimes resulted in numerical stability problems or root-missing problems. The purpose of this paper is to develop a systematic theoretical analysis of the dynamic characteristics of turbomachinery dual rotor-bearing systems. This dual rotor-bearing system analysis will start with a finite element (FEM) rotor-bearing system dynamic model, then using different methods to verify the analysis results including critical speed map and bearing stiffness. In an inertia coordinate system, a general model of continuous dual rotor-bearing systems is established based on a lagrangian formulation. Gyroscopic moment, rotary inertia, bending and shear deformations have been included in the model. From a point of view of the systematic approach, a solution of the finite element method is used to calculate the critical speeds by several different methods, which in turn can help to verify this dual rotor-bearing system approach. The effects of the speed ratio of dual rotors on the critical speed will be studied, which in turn can be used as one of the dual rotor design parameters. Also, both critical speeds are in effect functions of dual rotor speeds. Finally, the bearing stiffness between high speed and low speed shafts not only affect the critical speeds of the dual rotor system, but also affect the mode shapes of the system. Therefore, the bearing stiffness in between is of even greater importance in turbomachinery dual rotor or multiple rotor design.

Work system analysis of home nursing care and implications for medication errors

2005 ◽  
Author(s):  
K. L. Calvin ◽  
Gail R. Casper ◽  
Ben-Tzion Karsh ◽  
Patricia F. Brennan ◽  
Laura J. Burke ◽  
...  
Keyword(s):  
Medication Errors ◽  
Nursing Care ◽  
System Analysis ◽  
Home Nursing ◽  
Work System ◽  
Home Nursing Care

Offer of methods for minimizing key investment risks of “R-Pharm” JSC

2020 ◽  
Vol 17 (1) ◽  
pp. 58-67
Author(s):  
N. A. Kabanova ◽  
I. K. Alekseeva
Keyword(s):  
Strategic Planning ◽  
Pharmaceutical Company ◽  
Simulation Modeling ◽  
Return On Investment ◽  
System Analysis ◽  
Social Orientation ◽  
Pharmaceutical Companies ◽  
The Subject ◽  
High Degree

The article is devoted to the assessment of potential investment risks of the pharmaceutical company “R-Pharm” JSC with the aim of identifying the highest priority risks and developing methods for minimizing them. The relevance of the study is determined by the fact that the pharmaceutical business is characterized by a high degree of social orientation and annually invests $ 140 billion in the development of production and research, which determines the need for a risk-based approach to ensure the return on investment. The subject of this article is the investment risks of pharmaceutical companies, and the subject of research is the domestic pharmaceutical company “R-Pharm”. In order to assess the potential investment risks of “R-Pharm” JSC, the authors used elements of simulation modeling and system analysis. The proposed methods to minimize key investment risks are aimed at improving the efficiency of investment activities and is recommended as an element of the strategic planning of the company.

Sign in / Sign up

Export Citation Format

Share Document