NASTRAN THERMAL ANALYZER

260 Pages·2008·8.34 MB·English

https://ntrs.nasa.gov/search.jsp?R=19770016467 2018-11-27T06:21:16+00:00Z
N A SA TECHNICAL NASA TM X-3503
M E M O R A N D U M
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NASTRAN THERMAL ANALYZER -
THEORY AND APPLICATION INCLUDING
A GUIDE TO MODELING ENGINEERING PROBLEMS
Volume I
Hwa-Ping Lee
Goddard Space Flight Center
Greenbelt, Md. 20771
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. • APRIL 1977
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VAFB TiCHMSCAL UBBAKY
1.
Report No. 2. Government Accession No. 3. Recipient's Catalog No.
NASA TM X-3503
4. Title ond Subtitle 5. Report Date
Nastran Thermal Analyzer - Theory and April 1977
Application Including a Guide to Modeling
6. Performing Organization Code
Engineering Problems, Vol. 1 732
7.Author(s) 8. Performing Organization Report No.
Hwa-Ping Lee TM X3503
9. Performing Organization Name ond Address 10. Work Unit No.
506-17-33
Goddard Space Flight Center
Greenbelt, Maryland 20771
13. Type of Report and Period Covered
12.Sponsoring Agency Nome and Address
Technical Memorandum
National Aeronautics and Space Administration
Washington, D.C. 2U546
14. Sponsoring Agency Code
15.Supplementary Notes
16.Abstract
The NASTRAN Thermal Analyzer (NT A) is a new and unique general-purpose
heat transfer computer program based on the finite element method. It is an
integrated part of the NASTRAN system. To fill the needs of current and
potential NTA users who, in general, would neither be familiar with the under-
lying finite element theory nor have any prior experience in NASTRAN model-
ing, two volumes have been written to provide thermal engineers with a com-
prehensive and self-contained manual encompassing theory, application, and
examples of modeling.
This volume, The NASTRAN Thermal Analyzer Manual, is devoted to educating
the NTA users with the fundamental and the theoretical treatment of the finite
element method with emphasis on the derivations of the constituent matrices
of different elements and solution algorithms. Necessary information and data
relating to the practical applications of engineering modeling are included.
17. Key Words (Selected by Author(s)) 18. Distribution Statement
General heat transfer computer Unclassified - Unlimited
program, Finite element method,
Cat. 34
NASTRAN system
19. Security Clossif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price'
Unclassified ... Unclassified 248 $8.00
*For sale by the National Technical Information Service, Springfield. V.iFgini^:22161.
• *•> •
All measurement values are expressed in the International System of
Units (SI) in accordance with NASA Policy Directive 2220.4, paragraph 4.
FOREWORD
Without the guidance of a well prepared instruction and reference manual, a new user of the
NASTRAN Thermal Analyzer (NTA) may have difficulty in proceeding. Unless the user is
a member of a large team where at least one member is familiar with the finite-element
method and the NASTRAN modeling, he will have to search through widely scattered liter-
ature and documents before finding what he needs. Recognizing this problem, we have uti-
lized the knowledge and experience acquired during the development and application of the
NTA to provide essential and sufficient information required by those who use it.
With both beginners and experienced thermal analysts in mind, the NASTRAN Thermal
Analyzer Manual has been carefully designed to ensure a useful, comprehensive, and self-
contained document that encompasses the underlying theories, instructions of modeling
construction, descriptions of various data formats, and examples of engineering modeling.
The emphasis throughout has been placed on the practical aspects relevant to the use of the
NTA.
The first edition was published as two NASA/GSFC X-documents (X-322-76-16 and
X-322-76-17) in December 1975. Its contents evolved from the lecture notes used during
the in-house training course conducted in mid-May 1975. Source materials of this first
volume consisted of expanded extractions of published and unpublished works resulting
from research and development efforts in the development of the NTA, together with other
pertinent materials scattered in the three voluminous NASTRAN manuals of the Level 15.5
version.
The phenomenal number of requests for the two publications from both domestic and inter-
national users reflects the general enthusiasm and the rapidly expanding use of the NTA. It
is evident that the NTA is increasingly important for many space, military, and industrial
applications, particularly in unified thermo-structural analyses. To benefit NTA users, these
two volumes are to be published as formal NASA publications to ensure a wider distribution
and lasting availability.
H. P. Lee
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CONTENTS
Page
ABSTRACT i
FOREWORD iii
1. INTRODUCTION 1
1.1 A Brief History of the NTA Development 9
1.2 Distinctions Between the Finite Difference Method and the Finite
Element Method 15
1.3 The NASTRAN Thermal Analyzer Capabilities 17
2. FINITE ELEMENT THEORY IN HEAT TRANSFER
APPLICATIONS 19
2.1 Variational Principle 20
2.2 A One-Dimensional Steady-State Conducting Rod 23
2.2.1 Finite Element Formulation 23
2.2.2 Finite Element Formulation in Matrix Notation 30
2.3 Finite Element Formulation of a Two-Dimensional Triangular
Element 38
2.3.1 Conduction with Linear Boundary Conditions 38
2.3.2 Nonlinear Radiative Boundary Condition . 42
2.4 An Analogy Between Structural and Thermal Systems 46
2.5 Constituent Matrices for Various Elements 49
2.5.1 Heat Conduction Elements 49
2.5.2 Boundary Surface Elements 56
2.6 Methods of Solution . 61
CONTENTS (Continued)
Page
2.6.1 Linear Steady-State Thermal Analysis 61
2.6.2 Nonlinear Steady-State Thermal Analysis 64
2.6.3 Transient Thermal Analysis 71
2.7 Rigid Format DMAP Listings 77
2.7.1 DMAP Sequence for Linear Steady-State Thermal Analysis . . . . .. 78
2.7.2 DMAP Sequence for Nonlinear Steady-State Thermal
Analysis 84
2.7.3 DMAP Sequence for Transient Thermal Analysis 91
3. THE NASTRAN THERMAL ANALYZER INPUT DATA DECK 103
3.1 Overview of Thermal Model Preparation 103
3.2 General Description of Data Deck 109
3.3 Executive Control Deck 112
3.3.1 Executive Control Card Descriptions 112
3.3.2 Executive Control Deck Examples 116
3.4 Case Control Deck 118
3.4.1 Subcase Definition 118
3.4.2 Data Selection 119
3.4.3 Output Selection 120
3.4.4 Case Control Card Descriptions 121
3.5 Bulk Data Deck 138
3.5.7 Functional Description of Bulk Data Cards 138
3.5.2 Format of Bulk Data Cards 149
3.5.3 Bulk Data Card Descriptions 151
REFERENCES 245
VI
ILLUSTRATIONS
Figure Page
1.1 Representative heat conduction elements 5
- 1.2 The telescope in the OSO-I Colorado experiment 11
1.3 Conduction elements in the finite element thermal model of the telescope
in the OSO-I Colorado experiment 12
1.4 Boundary surface elements for radiative exchanges between the telescope
and the casing walls of the OSO-I Colorado experiment 13
1.5 The IUE telescope thermal model 14
1.6 Distinction between the finite difference lumped-nodal method and the
finite element method 15
2.1 True solution y(x) and trial function y(x,e) 21
2.2 Physical representation of a one-dimensional rod 24
2.3 Finite element representation of a one-dimensional rod 24
2.4 A 2-D triangular element 39
2.5 Representative heat conduction elements 50
2.6 Definition of a 1-D rod element and a 2-D triangular element 53
2.7 Formation of a 2-D quadrilateral element 55
2.8 An ELCYL type (elliptic cylinder) of the HBDY element 60
2.9 Simplified flow diagram for linear steady-state thermal analysis 62
2.10 Simplified flow diagram for nonlinear steady-state thermal analysis 65
2.11 Simplified flow diagram for transient thermal analysis 72
3.1 Thermal model functional diagram 104
3.2 A complete NASTRAN THERMAL ANALYZER input deck 110
3.3 Grid point sequencing for one-dimensional systems 141
3.4 Grid point sequencing for surfaces 141
3.5 Sample NASTRAN data input sheet 152
3.6 HBDY element orientation (for QVECT flux) 165
Vll
TABLES
Table Page
1.1 Cross-reference of the NTA sample problems vs. thermal analysis
features demonstrated 8
1.2 Number of model required for thermo-structural analysis including
radiative exchanges 16
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