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NASA/CR-2004-210725 A Six-Node Curved Triangular Element and a Four-Node Quadrilateral Element for Analysis of Laminated Composite Aerospace Structures C. Wayne Martin and David M. Breiner Martin Engineering Inc. Lincoln, Nebraska Under NASA Contracts NAS4-97007, NAS4-50079, NCA2-318, and NCA2-497 July 2004

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Page 1: A Six-Node Curved Triangular Element and a Four-Node ... · PDF file1.NAFEMS LE2 ... Element for Analysis of Laminated Composite Aerospace Structures 710-55-24-E8

NASA/CR-2004-210725

A Six-Node Curved Triangular Element and a Four-Node Quadrilateral Element for Analysis of Laminated Composite Aerospace Structures

C. Wayne Martin and David M. BreinerMartin Engineering Inc.Lincoln, Nebraska

Under NASA Contracts NAS4-97007,NAS4-50079, NCA2-318, and NCA2-497

July 2004

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NASA/CR-2004-210725

A Six-Node Curved Triangular Element and a Four-Node Quadrilateral Element for Analysis of Laminated Composite Aerospace Structures

C. Wayne Martin and David M. BreinerMartin Engineering Inc.Lincoln, Nebraska

Prepared forNASA Dryden Flight Research CenterEdwards, CaliforniaUnder NASA Contracts NAS4-97007,NAS4-50079, NCA2-318, and NCA2-497

July 2004

National Aeronautics andSpace Administration

Dryden Flight Research CenterEdwards, California 93523-0273

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NOTICE

Use of trade names or names of manufacturers in this document does not constitute an official endorsementof such products or manufacturers, either expressed or implied, by the National Aeronautics andSpace Administration.

Available from the following:

NASA Center for AeroSpace Information (CASI) National Technical Information Service (NTIS)7121 Standard Drive 5285 Port Royal RoadHanover, MD 21076-1320 Springfield, VA 22161-2171(301) 621-0390 (703) 487-4650

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iii

CONTENTS

Page

SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

ELEMENT PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

MATHEMATICAL DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

CONCLUDING REMARKS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

ACKNOWLEDGEMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

APPENDIX A: CURVED ELEMENT DEVELOPMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

APPENDIX B: MODIFICATIONS TO B

o

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

APPENDIX C: SHEAR PERPENDICULAR TO SURFACE IN FLAT ELEMENTS . . . . . . 28

APPENDIX D: STRAIN CALCULATION AT NODES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

APPENDIX E: OUT-OF-PLANE ROTATION STIFFNESS . . . . . . . . . . . . . . . . . . . . . . . . . 39

APPENDIX F: SIMULATED ANTI-SYMMETRIC BENDING MODE . . . . . . . . . . . . . . . . 42

APPENDIX G: 6-NODE FLAT SHEAR PANEL (USING 10 NODE SHAPE FUNCTIONS). . 45

TABLES

1.NAFEMS LE2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.NAFEMS LE3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.Scordelis-Lo Roof Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.Morley Skew Plate Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.Plunkette’s Vibrating Wedge Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6.NAFEMS T1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

7.Results for NAFEMS Laminated Strip. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8(a). NAFEMS LE2 Curved Shell Patch Test 1989 Results . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8(b). NAFEMS LE3 Pinched Hemisphere Shell 1989 Results . . . . . . . . . . . . . . . . . . . . . . . . 17

9.Error Summary for 6 and 8 Node Elements on Six Critical Test Cases. . . . . . . . . . . . . . . . . 18

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iv

FIGURES

Page

1.NAFEMS LE2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.NAFEMS LE3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3(a). Scordelis-Lo Roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3(b). Scordelis-Lo Roof Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4(a). Morley Skew Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4(b). Morley Skew Plate Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.Plunkett’s Vibrating Wedge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6.NAFEMS T1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

7.NAFEMS Laminating Strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

C.1. Sign Conventions and Shear Deformation Relations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

(a). Deformation in x-z plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

(b). Deformation in y-z plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

(c). Shear deformation without bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

C.2.Nodal Configurations and Interpolation Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

G.1. 10-Node Triangle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

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NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39-18298-102

A Six-Node Curved Triangular Element and a Four-Node Quadrilateral Element for Analysis of Laminated Composite Aerospace Structures

710-55-24-E8-RR-00-000

C. Wayne Martin and David M. Breiner

NASA Dryden Flight Research CenterP.O. Box 273Edwards, California 93523-0273

H-2469

National Aeronautics and Space AdministrationWashington, DC 20546-0001 NASA/CR-2004-210725

Mathematical development and some computed results are presented for Mindlin plate and shell elements,suitable for analysis of laminated composite and sandwich structures. These elements use the conventional3 (plate) or 5 (shell) nodal degrees of freedom, have no communicable mechanisms, have no spurious shearenergy (no shear locking), have no spurious membrane energy (no membrane locking) and do not requirearbitrary reduction of out-of-plane shear moduli or under-integration. Artificial out-of-plane rotationalstiffnesses are added at the element level to avoid convergence problems or singularity due to flat spots inshells. This report discusses a 6-node curved triangular element and a 4-node quadrilateral element. Findingsshow that in regular rectangular meshes, the Martin-Breiner 6-node triangular curved shell (MB6) isapproximately equivalent to the conventional 8-node quadrilateral with integration. The 4-nodequadrilateral (MB4) has very good accuracy for a 4-node element, and may be preferred in vibration analysisbecause of narrower bandwidth. The mathematical developments used in these elements, those discussed in theseven appendices, have been applied to elements with 3, 4, 6, and 10 nodes and can be applied to other nodalconfigurations.

2 2×

Aerospace engineering, Composites, Curved elements, Finite element, Structural design

58

Unclassified Unclassified Unclassified Unlimited

July 2004 Contractor Report

This work was done as partial fulfillment for contract numbers NAS4-97007, NAS4-50079, NCA2-318, and NCA2-497ranging from 1991–1998. NASA Technical Monitor – Kajal K. Gupta, NASA Dryden Flight Research Center.

Unclassified—UnlimitedSubject Category 05

This report is available at http://www.dfrc.nasa.gov/DTRS/