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Advances in compositestructures design and simulationTRAINING MODULES

for Researchers

Volume 3

2015

National Aerospace University

“KhAI”


for Researchers

Volume 3

2015


“KhAI”


for Researchers

Volume 3

2015


“KhAI”

Advances in composite structuresdesign and simulation

Volume 3

TRAINING MODULES

for Researchers

Prepared in the frame of the FP7 KhAI-ERA project activities

2015

Institute of Aerospace Engineering - Brno University of Technology “IAE-BUT”


Volume 3

TRAINING MODULES

for Researchers


2015



Volume 3

TRAINING MODULES

for Researchers


2015


Published by the National Aerospace University “KhAI” in 2015

Advances in composite structures design and simulation

This training modules collection was jointly prepared by the National Aerospace University “KhAI” andInstitute of Aerospace Engineering, Brno University of Technology (IAE-BUT) in the frame of FP7 KhAI-ERAproject training development activities. It is intended for researchers interested in composite structures.Included to this issue training modules are presentations of buckling and post-buckling simulationsincluding post-processing and examples; nonlinear explicit FE analysis application for impact problemssimulation, and finite element modelling and analysis using Python.

Reproduction is authorised provided the source is acknowledged. No use of this publication may be madefor resale or for any other commercial purpose.

Available on-line at http://khai-era.khai.edu/en/site/training-modules.html

For enquiries, inputs and feedback on the use of this document please contact:

International S&T Projects Office

National Aerospace University “KhAI”

17Chkalova str., Kharkov, 61070, Ukraine

Phone: +38 (057) 788 40 60

Fax: +38 (057) 719 04 73

e-mail: [email protected]

LEGAL NOTICE

Neither the European Commission nor any person acting on behalf of the Commission is responsible for theuse, which might be made, of the following information.

The views expressed in this report are those of the authors and do not necessarily reflect those of theEuropean Commission.

© KhAI-ERA Consortium, 2015

Foreword

This material arose by the KhAI-ERA project as a result of knowledge exchange by researchers of Institute ofAerospace Engineering - Brno University of Technology (hereinafter IAE-BUT) to researchers of NationalAerospace University (hereinafter KhAI).

The publication shows the collection of training modules where aspects and examples of advanced finiteelement analysis methods application for composite aeronautic structures are presented.

Assoc. prof. Jaroslav JuračkaInstitute of Aerospace Engineering - Brno University of Technology

Authors

Assoc. prof. Jaroslav JuračkaIAE-BUT

Assoc. prof. Juracka is Director of the IAE-BUT. His research is focussed onaircraft design, structural analysis, composite structures, and aircrafttesting. He has considerable experience of applied industrial projectsincluding – CEDESA (coordinator, FP7, 2010-2014), Development of VUT 001Marabu aircraft for UAV applications (2006-2009), Development of EV-55airplane in cooperation with EVEKTOR (2005-2010), Development ofVUT100 Cobra aircraft (2002-2006), Cost Effective Small Aircraft - CESAR(FP6 Project, 2006-2009)

Dr. Michal MališIAE-BUT

Dr. Michal Mališ is a researcher of NETME Centre. He participates innational projects named “Advanced Aerostructures Research Centre” and“Crash”. His research is focused on crashworthiness of light aircrafts andfinite element method simulations of statically and dynamically loaded thin-walled structures, mainly made out of composite materials. He wasresponsible for stress analyses and design of supporting structures fromcomposite materials of VUT 001 Marabu, VUT 061 Turbo and VUT 081KONDOR aircrafts. He is author of the COMPOST software - COMpositePOST processor for finite element solvers.

M.Sc. Volodymyr SymonovIAE-BUT

Volodymyr Symonov is a researcher of NETME Centre. He participates in thenational project named “Advanced Aerostructures Research Centre”. Hisresearch is focused mainly on aircraft structures made of compositematerials. Particularly his scientific interests are connected with estimationof aircraft primary structures life, metal-composite and composite-composite joints design, stress analysis, tests and finite element simulationsof statically and dynamically loaded thin-walled structures and joints. Heparticipated in stress analysis and finite element simulations of L410 NGaircraft within MOSTA project and also participated in FP7 CEDESA project.

Authors







Authors







M.Sc. Pavel SchořIAE-BUT

Pavel Schoř is a PhD. student at Institute of Aerospace Engineering.His PhD. research is mainly focused on numerical solving of staticaero-elastic problems, but he is also involved in structural problems.He is co-designer of composite landing gear spring for VUT 061 Turboairplane and co-author of the COMPOST software.

Content

Module 1 Post-buckling simulations and post-processing including examples 10Dr. Michal Mališ, IAE-BUT

Buckling Problem 13

Outline 14

Example problem. Thin-walled unstiffened cylinder 14

Parameters affecting buckling load analysis 16

Parameters affecting FEM analysis results 17

Analytical solution 17

Influence of Plies orientation 20

Comparison of FEA and analytical solution results 20

Geometrical imperfection Analysis 23

Module 2 Nonlinear explicit FE analysis application for impact problemssimulation 30

M.Sc. Volodymyr Symonov, IAE-BUT

Explicit and Implicit Methods 33

Bird Strike Simulations 35

MSC Nastran/Dytran Material Models 37

Modelling of Interlaminar Delamination 38

Contact Modelling 38

Module 3 FE modelling and analysis using Python 40

M.Sc. Pavel Schoř, IAE-BUT

Example problem 44

Introduction to Abaqus scripting 50

Example - flat plate with mesh 50

Material imperfections 51

Module for creating imperfect plates 53

Module 1 – Post-Buckling Simulations and Post-Processing Including Examples

Prepared in the frame of the FP7 KhAI-ERA project 11

Training Module 1

Post-Buckling Simulations and Post-ProcessingIncluding Examples

Dr. Michal Mališ

IAE-BUT

2015



Introduction

Thin-walled structures are widely used in aerospace vehicles. A simple representative of such a structurecan be a thin-walled cylinder. The most critical failure mode for this type of structures is buckling.Therefore, it is very important to correctly define the buckling load of the structure. The results of FEbuckling simulations depend on many aspects including material model used and special numericalparameters such as time step, etc. Therefore, it is very important to select appropriate parameters in orderto obtain correct simulation results including correct post-buckling behavior of the structure.

This module describes how to adjust FE model of an axially compressed thin-walled unstiffened cylinder inorder to meet correlation with test results, and analytical solution.

One of the aspects influencing the correlation between the simulation and test results is imperfectionsoccurred in a real structure which weaken the structure leading to lower buckling load. Several approachesfor imitating imperfections in FE models are described and compared in the module.

Module components

Buckling of thin-walled unstiffened cylinders

FEA vs. analytical solution results

Geometrical imperfections

Target audience

doctoral and master students, researchers


14 Prepared in the frame of the FP7 KhAI-ERA project

Reference [6]



Reference [6]



Reference [6]



References

1. Geier,B., Meyer-Piening, H., Zimmermann, R.: „On the influence of laminate stackingsequences of composite cylindrical shell subjected to axial compression”, Compositesstructures, 55, page 467-474, 2002.

2. Degenhardt R., Kling A., Rohwer K., Orifici A. C., Thomson R. S., “Design and Analysis ofStiffened Composite Panels Including Postbuckling and Collapse”, Computers and StructuresVol. 86 (2008), pp. 919-929

3. Hühne,C., Rolfes,R., Breitbach, E., Tessmer, J.: „Robust design of composite cylindrical shellsunder axial compression – Simulation and validation ”, Thin-Walled Structures, 46, page 947-962, 2008.

4. Kriegesmann, Benedikt:, „Probabilistic Design of thin-walled fiber composite structures”,Dissertation. Leibnitz Universität Hannover, 2012.

5. Steinmüler, Patrick:, „Investigation of axially loaded unstiffened CFRP cylindrical shellssubjected to single perturbation loads”, Master thesis, Private university of applied scienceGöttingen, 2008.

6. FP7 DESICOS project: [web-site]. URL: http://www.desicos.eu (reference date: 01.04.2015)

Module 2 – Nonlinear Explicit FE Analysis Application for Impact Problems Simulation


Training Module 2

Nonlinear Explicit FE Analysis Application forImpact Problems Simulation

M.Sc. Volodymyr Symonov

IAE-BUT

2015



Introduction

The impact analysis requires complex multidisciplinary approach. The best way to assess the impactresistibility of a structure is a real experiment which is very expensive. A good alternative to the experimentcan be FE simulations. Because impact is a dynamic transition process special FE methods should be usedfor its simulation called implicit and explicit analyses.

The current module describes the differences and application scope of explicit and implicit methods.

Bird strike FE analysis represents the explicit method application for impact problem simulation. The mainaspects of bird strike analysis are described in the module.

Module components

Explicit vs. Implicit FEA methods

Bird Strike Simulation Major Aspects

Target audience




References

7. MSC Nastran 2013 Explicit Nonlinear (SOL 700) User’s Guide.

8. Tho, C.H., Smith, M.R. : „Accurate bird strike simulation methodology for ba609 tiltrotor”,Journal of the American Helicopter Society, 56(1), pp.12007, 2011.

9. Heimbs, S.: “Computational methods for bird strike simulations: A review”, Computers andStructures, 89, page 2093-2112, 2011.

10. Lavoie, M.A., Gakwaya, A., Ensan, M.N., Zimcik, D.G., Nandlall, D.: “Bird’s substitute testsresults and evaluation of available numerical methods”, International Journal of ImpactEngineering, 36, page 1276–1287, 2009.

11. Hedayati, R., Sadighi, M., Mohammadi-Aghdam, M.: “On the difference of pressure readingsfrom the numerical, experimental and theoretical results in different bird strike studies”,Aerospace Science and Technology, 32, page 260–266, 2014.

12. Heimbs, S., Bergmann, T., Schueler, D., Toso-Pentecôte, N.: “High velocity impact onpreloaded composite plates”, Composite Structures, 111, page 158-168, 2014.

13. Abdullah, E., Ferrero, J.-F., Barrau, J.-J., Mouillet, J.-B.: ”Development of a new finite elementfor composite delamination analysis”, Composites Science and Technology, 67, page 2208–2218, 2007.

14. Heimbs, S.: “Bird Strike Simulations on Composite Aircraft Structures”, 23rd SIMULIACustomer Conference, May 17-19, 2011, Barcelona, Spain.

Module 3 – FE Modelling and Analysis Using Python


Training Module 3

FE Modelling and Analysis Using Python

M.Sc. Pavel Schoř

IAE-BUT

2015



Introduction

Many specific structural analysis problems require flexible and complex approach which cannot beachieved with conventional application of FE modelling and analysis. These aspects can be covered withhelp of joining FE modelling and programming capabilities. One of the most worldwide spreadprogramming languages for engineers is Python.

This module describes how to apply Python for FE modelling of a specific problem in Abaqus based on anexample problem which is connected to imperfect composite parts.

Module components

Application of Python for FE modelling

Example problem. Simulations of imperfect composite parts

Target audience




References

1. Abaqus user manual.

2. Abaqus scripting manual.

3. Python for aerospace engineers.

4. Example scripts.

5. BMP2TI Utility.

Prepared under the aegis of KhAI-ERA projectfunded by the European Commission’s Directorate-Generalfor Research & Innovations under the FP7 CapacitiesSpecific Programme on International CooperationGrant Agreement no 294311National Aerospace University

“KhAI”17 Chkalova str., Kharkiv

61070 Ukrainewww.khai.edu







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