• Title, Summary, Keyword: analytical substructure

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A hybrid method for dynamic stiffness identification of bearing joint of high speed spindles

  • Zhao, Yongsheng;Zhang, Bingbing;An, Guoping;Liu, Zhifeng;Cai, Ligang
    • Structural Engineering and Mechanics
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    • v.57 no.1
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    • pp.141-159
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    • 2016
  • Bearing joint dynamic parameter identification is crucial in modeling the high speed spindles for machining centers used to predict the stability and natural frequencies of high speed spindles. In this paper, a hybrid method is proposed to identify the dynamic stiffness of bearing joint for the high speed spindles. The hybrid method refers to the analytical approach and experimental method. The support stiffness of spindle shaft can be obtained by adopting receptance coupling substructure analysis method, which consists of series connected bearing and joint stiffness. The bearing stiffness is calculated based on the Hertz contact theory. According to the proposed series stiffness equation, the stiffness of bearing joint can be separated from the composite stiffness. Then, one can obtain the bearing joint stiffness fitting formulas and its variation law under different preload. An experimental set-up with variable preload spindle is developed and the experiment is provided for the validation of presented bearing joint stiffness identification method. The results show that the bearing joint significantly cuts down the support stiffness of the spindles, which can seriously affects the dynamic characteristic of the high speed spindles.

A Symbolic Manipulation Computer Program for Structural Analysis (구조해석(構造解析)을 위한 Symbolic Manipulation Program)

  • Shim, Jae Soo
    • Journal of The Korean Society of Civil Engineers
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    • v.3 no.4
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    • pp.95-107
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    • 1983
  • The general purpose programs are in their fixed algorithm and theory of mechanics which can not be altered without painful program modifications. Users are usually guided by user's manual for data input. The several symbolic manipulation programs for structural analysis are introduced recently. These programs allow users to include a wide class of solution algorithm and to specify, by means of some symbolic manipulation, a combination of analytical steps to suit a particular problem. As they can solve a single domain problem, a large computer is usually needed. The scope of this study is to develop an efficient symbolic manipulation program with space beam element, plate bending element and eigen value routines. The incorporated Substructure capability and generation capability of finite element characteristic arrays (e.g., stiffness matrix, mass matrix) enables users to analyse multidomain problem with small computer. The program consists of modulized independent processors, each having its own specific function and is easily modified, eliminated and added. The processors are efficiently handling data by the Data base approach which is the concept of integrated program network(IPN).

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Development of Structural Analysis and Pre-post Program for Mega Frame System (초대형 골조시스템 전용 전후처리 및 해석프로그램의 개발)

  • Kim Hyun-Su;Lee Dong-Guen
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.3
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    • pp.283-293
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    • 2006
  • Recently, various types of structural systems for skyscrapers are studied as the height and size of the building structures rapidly increase due to social and economical needs. The mega frame system among them, which is the structural system developed recently, is known as a suitable structural system for skyscrapers because this structural system has sufficient stiffness against the lateral forces by combination of mega members which consist of many columns and girders. Since the mega frame structure has significant numbers of elements and nodes, it takes tremendous times and computer memories to analyze and design the structures. Therefore, the exclusive structural analysis program for mega frame system is developed to reduce the efforts and time required for the analysis and design of mega frame structure. To this end, an efficient modelling technique using the characteristics of mega frame structures and an efficient analytical model, which uses a few DOFs selected by the user using the matrix condensation method, are developed in this study. Static and dynamic analyses are conducted using an example structure. The effectiveness and accuracy of the developed program we verified by the comparison between the results of the proposed method and the conventional method.