Numerical Methods and Tools Development in VULCAN: Tools ... · Microsoft PowerPoint - 03-VULCAN Industrial Seminar UoP.ppt Author: 102955 Created Date: 3/1/2011 11:06:53 AM

Industrial Seminar23rd Feb. 2011

AST5‐CT‐2006‐031011: VULCAN

Numerical Methods and Tools Numerical Methods and Tools Development in VULCAN: Tools and Development in VULCAN: Tools and

Methods developed for blast analysis of Methods developed for blast analysis of aircraft structuresaircraft structures

VULCAN INDUSTRIAL SEMINARVULCAN INDUSTRIAL SEMINAR

organised byorganised by

Dr Dimitris VlachosDr Dimitris VlachosUniversity of PatrasUniversity of Patras



The VULCAN approachThe VULCAN approach

ScopeScope: To develop the necessary numerical models to simulate the blast response of fuselage structures and utilise them to design hardening measures.

Basic conceptBasic concept: Modelling and analysis efforts backed by a testing campaign meant for the validation of the various modelling schemes applied (material behaviour, interface and contact modelling, development of damage)



BuildingBuilding--block testing and analysisblock testing and analysis

coupons

structural details

sub-component

component

1. Blast tests on flat panels

2. Castellation assemblystudy/ sandwich floor

3. Curved panels with frames and stringers

4. Fuselage section




coupons

structural details

sub-component

component

1. Blast tests on flat 1. Blast tests on flat panelspanels

2. Castellation assembly study/ sandwich floor


4. Fuselage section



1. Blast tests on flat panels1. Blast tests on flat panels



1. Blast tests on flat panels1. Blast tests on flat panels

Investigation of various modelling options, schemes- Shell-solid element- Material models- Contact interfaces - CONWEP vs ALESelection-calibration of appropriate material modelsDamage modelling (criteria – post-failure options)



1. Modelling of the sandwich material (floor)1. Modelling of the sandwich material (floor)• GFRP skins and Nomex honeycomb

core• Data provided from data sheets and

existing literature * (6 stress-strain curves required for honeycomb), strain rate effects incorporated

• 2 solid elements through the thickness for the core, shell elements for the skins

• Dedicated co-rotational solid elements for honeycomb material model

• Delamination incorporated by tiebreak contact

(*) S. Heimbs et. al., “Numerical Simulation of Aircraft Interior Components under Crash Loads”, International Journal of Crashworthiness, Vol.13, No5, October 2008, 511-521




coupons

structural details

sub-component

component


2. Skin2. Skin--stringer attachmentstringer attachment


4. Fuselage section



2. Castellation assembly study2. Castellation assembly study



2. Castellation assembly study2. Castellation assembly study

Validation of simulation models against test resultsDetermination of important model parameters- Type of contact interfaces- Contact failure parameters




coupons

structural details

sub-component

component


2. Skin-stringer attachement/ sandwitch floor


4. Fuselage section4. Fuselage section




• Size and configuration typical of an Airbus 320 fuselage.

• Simplified structure (no windows, doors or other details)

• 4m diameter, 6m length section

• Arbitrary Lagrangian-Eulerian formulation




Analysis procedure1. Initialization – Application of flight loads2. Blast loading3. Application of flight loads to the damaged structure

Approximation of static, quasi-static processes via the Dynamic Relaxation capability. Accuracy verified with static analysis performed with MSC-Nastran




coupons

structural details

sub-component

component


2. Skin-stringer attachement/ sandwitch floor





Study of blast response of fuselage sectionStudy of blast response of fuselage section

Charge locations1. 20cm from the fuselage skin

and 20cm from the floor2. 20cm from the fuselage skin

and 5cm from the floor3. 20cm from the skin and 50cm

from the floor4. At the height of the luggage

compartment and 20cm from the skin

5. As 1 above opposed to a frame6. As 2 above opposed to a frame




Debonding of GLARE skin1000μs after detonation

Debonding of GLARE skin after the re-application of the flight loads




Damage to a GLARE skin fuselage model Rupture of a frame




Damage to a CFRP fuselage modela. 1st plyb. 5th plyc. 10th ply

a

b c




Contact interface separation (Delamination) – CFRP fuselage




Damage on frames – CFRP fuselage




Damage to stringers – CFRP fuselage



Improving blast performanceImproving blast performance

Work performed by Boeing

Panel made from Kevlar 745 plain weave fabric with Cytec Cycom 2282 resin

about 10mm thick, so rather HEAVY!!



Design of blast hardening measuresDesign of blast hardening measures

polycarbonate Kevlar laminate




Folded core sandwich panel

• Folded core developed during FP6 project CELPACT

• Sandwich structures are commonly used in interior parts

• Has similar crushing performance with honeycomb cores

• Low weight - Easy to manufacture• Modelling parameters are published

in literature




Conventionalpolycarbonate liner




Aramid fibre composite liner




Sandwich material composite liner




Polycarbonate, weight: 4 kgmax stress: 300MPa

Folded core sandwich, weight: 2.2 kgmax stress: 228MPa

Effective stress contours



Thank you for your attentionThank you for your attention

For more info and details of the work presented you can refer to:1. T. Kotzakolios, D.E. Vlachos and V. Kostopoulos, “Blast response of metal

composite laminate fuselage structures using finite element modelling”, Composite Structures 93, 2011, pp. 665–681

2. T. Kotzakolios, D.E. Vlachos and V. Kostopoulos, “Investigation of blast response of GLARE laminates: comparison against experimental result”, Plastics, Rubber and Composites, 2011, Article in press

3. T. Kotzakolios, D.E. Vlachos and V. Kostopoulos, “On the blast response of sandwich aerospace composites”, Composites Part B, submitted for publication.

The UoP “VULCAN” Team:Prof. V. KostopoulosDimitris VlachosThanasis KotzakoliosDimitris Sikoutris

Contributions from:RMA, WUT, TNO, SENER

Documents

Numerical Methods and Tools Development in VULCAN: Tools ... · Microsoft PowerPoint - 03-VULCAN Industrial Seminar UoP.ppt Author: 102955 Created Date: 3/1/2011 11:06:53 AM