Simulation of the Damage and Failure Behaviour of Flow Drill … · © VIRTUAL VEHICLE Flow Drill...

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COMET K2 Competence Center - Initiated by the Federal Ministry of Transport, Innovation & Technology (BMVIT) and the

Federal Ministry of Science, Research & Economics (BMWFW). Funded by FFG, Land Steiermark and Steirische Wirtschaftsförderung (SFG)

Simulation of the Damage and Failure Behaviour of Flow Drill Screw

Joints between Fibre-Reinforced Plastics and Aluminium by using User-

Materials Szlosarek, R.a, Karall, T.a, Hahne, C.b, Berger, A.c, Meyer, N.d, Enzinger, Ne

aVirtual Vehicle Research Center

bAUDI AG cEngineering System International GmbH

dTU Darmstadt, Fachgebiet Konstruktiver Leichtbau und Bauweisen eTU Graz, Institut für Werkstoffkunde und Schweißtechnik

Motivation

22.05.2014 Numerical Modelling of the Damage and Failure Behaviour of Flow Drill Screw Joints

between Fibre-Reinforced Plastics and Aluminium 2

oUS-NCAP

o 56 km/h

o rigid wall

oChrysler Neon

Flow Drill Screw Joints between CFRP-Aluminium

09.10.2014 Simulation of the Damage and Failure Behaviour of Flow Drill Screw Joints between

Fibre-Reinforced Plastics and Aluminium by using User-Materials 3

micrograph test specimen

flow drill screw

aluminium

only a one-sided accessibility is necessary

low thermal impact

minor requirements for part preparation

chipless process the thread in the aluminium part is perfectly connected to the screw with no clearances

Joining Process

(1) Placement of the screw in the pre-hole

(2) Forming of the through draught

(3) Yielding of the aluminium starts

(6) Pre-stressing of the screw by a defined torque

Roadmap

experiment detailed simulation

Flow drill screw joint between CFRP - aluminium

ViF K2 Projekt: Audi, ESI, KLuB, IWS

analogous model

Roadmap

experiment

Modified KSII-Test Facility

test specimen

aluminium: EN-AW6060-T6; thickness 2,5 mm

CFRP: laminate with 8 layers (0/90/45/-45)s;

thickness 1,2 mm

modified LWF KS2 test facility of the Laboratory for Materials and

Joining Technology of the University of Paderborn

Experiment

Damage and Failure under Cross Tension

Video recording of the damage and failure behaviour under cross tension

Damage and Failure under shearing Load

• good reproducibility of the tests

• bearing as dominant failure mode

Force-Displacement-Curves

• nearly the same maximum force under all tested loading angles for the tested

combination of CFRP and aluminium

Test results under various loading angles

Roadmap

Why a Detail Simulation?

Modelling of the elastic behaviour

Simulation of the damage and failure behaviour

Study of additional loading situations

Analysis of other material combinations

virtual design

real experiments numerical experiments

Finite Element Model

Finite element model Real test facility

• Using symmetries and the results of the optical displacement measurement

reduction of the model

reduction of computation time within the same result quality

Pre-load of the Joint

1. Stage: pre-load of the screw

to take the joining process into account

2. Stage: loading of the screw

strength analysis

Multi-stage analysis to regard the pre-stressing

stress transfer

Pre-load of the Joint

stress σ3

Pre-stress of the laminat

Material Modelling

Screw, aluminium, clamp

rigid body

Test facility (steel S370 and aluminium)

material models are available

CFRP, 8 layers (0/90/45/-45)s

user-material by using the inter-fibre

failure criteria of Puck

Material Models

User-material model

transformation of the stresses into an action plane

determination of the fracture angle is mandatory

- inter-fibre fracture criteria of Puck is based on the fracture hypothesis of Mohr

Modelling of inter-fibre fracture

Modelling of the Degradation

Modelling of an increasing crack density (smeared crack modelling)

stress-strain extrapolation method after Schürmann

the stress is kept constant with an increasing crack density

no additional stress could be transferred after inter-fibre fracture occurs

Degradation model

• Stresses on the action plane are kept constant

degradation model depends

on the fracture angle!

constant:

Degradation model

Example: single element σ3 in GPa

Roadmap

analogous model

Analogous Model

Using shell and beam elements for large structures

- non-linear force-displacement-curves

- user-defined rupture model

- usage of MPC-Links

(0/90/45/-45)s shearing load (0/90/45/-45)s cross tension test

displacement

Link-Element

simulation

average tests

test 1

test 2

test 3

simulation

average tests

test 1

test 2

test 3

displacement

Visualization of the LINK Elements

Example: multi material profile

- length for the normal force

- diameter for the shearing force

- colours for the damage

Aluminium

Visualization of the LINK Elements

Example: crushing test

damage

Conclusion

Modified test facility and data analysis due to test specimens

made of CFRP

User-defined material model which enables a detailed

simulation of the damage and failure behaviour of FRP

Analogous model for the use joint modelling in large

structures

The authors would like to acknowledge the financial support of the "COMET K2 - Competence Centres for Excellent Technologies Programme" of the Austrian

Federal Ministry for Transport, Innovation and Technology (bmvit), the Austrian Federal Ministry of Science, Research and Economy (bmwfw), the Austrian

Research Promotion Agency (FFG), the Province of Styria and the Styrian Business Promotion Agency (SFG).

The authors would, furthermore, like to express their gratitude to their supporting industrial and scientific project partners, namely Audi AG, ESI GmbH, Institut

für Werkstoffkunde und Schweißtechnik at Technical University of Graz, Fachgebiet Konstruktiver Leichtbau und Bauweisen at Technical University of

Darmstadt.

Robert Szlosarek robert.szlosarek@v2c2.at www.v2c2.at

Thomas Karall thomas.karall@v2c2.at www.v2c2.at

Clemens Hahne clemens.hahne@audi.de www.audi.de

André Berger Andre.Berger@esi-group.com www.esigmbh.de

Nils Meyer nils.meyer@klub.tu-darmstadt.de www.klub.tu-darmstadt.de

Norbert Enzinger norbert.enzinger@tugraz.at iws.tugraz.at

Simulation of the Damage and Failure Behaviour of Flow Drill … · © VIRTUAL VEHICLE Flow Drill...

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