Dynamics in Aircraft Engineering Design and Analysis for Light … · 2015-11-06 · structural models. of subcomponents, and complex dynamic behaviors can be reproduced in less time,

Dynamics in Aircraft Engineering Design and Analysis for Light Optimized Structures (DAEDALOS)

Chiara Bisagni

Politecnico di Milano, Department of Aerospace Engineering, Milan, Italy

Outline

AERODAYS 2011, Madrid, Spain, 30th March – 1st April 2011

Project summary Partners Background Motivation Objectives Aircraft configuration Methods of load analysis Testing activities Work in progress

DAEDALOS

Dynamics in Aircraft Engineering Design and Analysis for Light Optimized Structures

Collaborative Project Level OneCall identifier: FP7-AAT-2010-RTD-1AAT.2010.1.1-2 AerostructuresStart date: November 1, 2010Duration: 36 Months

Total costs: Euro 5,857,184.68EU contribution: Euro 3,962,468.00

Coordinator: Prof. Chiara BisagniPolitecnico di Milano, Department of Aerospace Engineering, Milano, ItalyE-mail: [email protected]


DAEDALOS Partners

Politecnico di Milano (POLIMI) Alenia Aermacchi SPA (AAEM) Aernnova Engineering Solutions SA (AES) Advanced Lightweight Engineering B.V. (ALE) Vysoke uceni technicke v Brne (BUT) Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) Totalforsvarets Forskningsinstitut (FOI) Israel Aerospace Industry LTD. (IAI) Letov Letecka Vyroba Ltd. (LLV) Gottfried Wilhelm Leibniz Universität Hannover (LUH) Rheinisch-Westfälische Technische Hochschule Aachen (RWTH) SMR Engineering & Development (SMR) Technion - Israel Institute of Technology (TECHNION)


DAEDALOS Background

Airworthiness regulations and requirements; Available materials / material data; Required structural details; Environmental considerations; Manufacturing capabilities; Affordability.

The design of civil aircraft structures are heavily influenced by severalcriteria which include:

Improvement in material research and assembly methods have led to anincreased use of composite materials, up to 50% of the weight of theairframe (Boeing 787 Dreamliner and Airbus A350 XWB).

The introduction of composite materials also led to an increased use oftitanium and more in general of hybrid-structure aircraft, where for eachpart the most suitable material/design compromise is found.


DAEDALOS Background

The structural response is more complex due to the different materialsinvolved, and requires research and innovative procedures in the detailedknowledge of the actual loads with dynamic effects and in the responseof the aircraft including damping.

Ti: Landing gears, pylons, attachments

CFRP: Skin, stringer, frames, centre wing box, keel beam, empennage, doors

Al/Al-Li: Ribs, floor beams, landing gear bays


DAEDALOS Motivation

Dynamic loading conditions became more important as aircraft structuresevolved into lighter and more flexible, and represent a significant part ofthe design envelope.

Today, detailed time history loads exist for aircraft as well as detailedstructural models of subcomponents, and complex dynamic behaviorscan be reproduced in less time, as computing power increases.

The progress in the Dynamic Loads Analysis has not quite beenmatched with a corresponding improvement in the way the dynamic loadsare applied and analyzed within the structural models.

The dynamic loads are converted into quasi-static load sets which are thenapplied into the large stress FEM. These current methods do not take intoaccount effects such as dynamic buckling, material damping andmechanical hysteresis.


DAEDALOS Objectives

The objectives of DAEDALOS are: To investigate the influence of dynamic loading on the structural

behavior as buckling, post-buckling and collapse of typicalaerospace structures made of CFRP and the effect of structuraldamping on load redistribution;

To develop techniques benefiting from the current analytical toolsand computer power which can use the loads obtained from DynamicLoads Analyses into the more complex full FEM, consideringdamping characteristics, dynamic buckling and hysteresis;

To predict the realistic section forces along the fuselage structure,considering also the energy dissipation around the load introduction;

To redefine a more realistic set of design loads able to guaranteesignificant weight reduction and increasing safety for future aircraft.


Structure of DAEDALOS project

WP2Structural Models andLoad Cases Definition

WP3Application of

Dynamic Loading

WP4Structural Testing

WP5Design Guidelines and

New Technology Validation

WP1Management,

Dissemination andExploitation


Aircraft configuration


The generic aircraft model represents a mid-size business jet with the following characteristics:Max. Take-Off Weight: 12300 kgMax. Landing Weight: 10200 kgWing Ref. Area: 32.38 m2

Wing Span: 15.38 mOverall Length: 15.60 m

Aircraft configuration


Current method of load analysis


Choose critical load conditions based on maximum fuselage sectional loads

Critical load conditions are selected as single static force distributions

Calculate loads distribution using stick model integrated with non linear landing gear model

BENDING MOMENT VS TIME

0 0.1 0.2 0.3 0.4 0.5 0.6


Critical load conditions are transferred to full FEM

Critical cases are run as static load cases in full FEM

Sizing is done based on results of static cases from full FEM

Sizing

Current method of load analysis

Loads analysis based on full FEM


Run time response with landing gear forces on full FEM

Compare stress/strain values to critical values obtained with conventional method

Sizing based on stress time history

Fx = f(t)

Fz = f(t)

Analyze stress/strain time response for specific structural elements

Structural components


Aft pressure bulkhead

Fwd engine beam frame attach.

Load condition: Dynamic load due to hard landing


Load condition: Lateral gust



Load condition: Vertical gust


Testing activities


The testing activities will be performed on specimens and structural components: Specimens for material damping

Material: Al, CFRP UD and CFRP fabricTested by RWTH and TECHNION

Testing activities


The testing activities will be performed on specimens and structural components: Specimens for material damping Flat and curved panels

Panels: Al, CFRP and sandwichTested by POLIMI, BUT, RWTH

and TECHNION

Testing activities


The testing activities will be performed on specimens and structural components: Specimens for material damping Flat and curved panels Cylindrical shells

Material: CFRPTested by POLIMI, DLR and TECHNION

Work in progress


DAEDALOS started five months ago and will end in October 2013

If you are interested to know more about the project and to stay update with the work in progress, please visit the project websitewww.daedalos-fp7.eu

The results will be presented in a final workshop in Milano: you are already invited to participate!

Documents

Dynamics in Aircraft Engineering Design and Analysis for Light … · 2015-11-06 · structural models. of subcomponents, and complex dynamic behaviors can be reproduced in less time,