CONTRIBUTION TO BMW i.

INCREASED FRONTLOADING OF AUTOMOTIVE CFRP DEVELOPMENT TASKS USING EXTENDED VIRTUAL PROCESS CHAINS.

Markus Dix,

LCC 5th Anniversary Symposium

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 3

AGENDA.

1. Motivation

2. Problem description

3. Solutions with simulation methods

4. Enhanced simulation models

5. Validation and qualification

6. Examples – BMW i

7. Summary and outlook

MOTIVATION.

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 5

BMW i3 BMW i8

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 7

PROBLEM DESCRIPTION. RTM PROCESS CHAIN.

Nur Großbauteile

Targets:

Design of machines,

tools and processes

Fiber quality Drapability Ability for injection

Overlapping

areas

Ability

for

injection Dimensional stability Examples of interrelationships

inbetween sequential process

steps

Stack-

prozess

Preformen &.

Preform-

schneiden

Konfektionieren

(Verbinden der

Preformlinge)

Endbeschnitt

(Wasserstrahl-

schneiden)

Gelege-

herstellung

Faser-

herstellung

Korund-

strahlen

Stacking

process

Preforming &

Cutting Assembly

Trimming

(water jet

cutting)

Textile

manufacturing

Fiber

production

Corundum

blasting

RTM Vacuum

Injection

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 9

SIMULATION METHODS. OVERVIEW OVER RTM PROCESS CHAIN.

Filling simulation Draping simulation Warpage simulation

Current design of Preforming Tool Current design of

RTM Tool

Iteration loops

feasability for manufacturing

Warpage compensation

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 10

SIMULATION METHODS. DRAPING SIMULATION.

Information from

multiple layers

Fiber orientation (UD 0° layer)

Shear angle

(UD 0° layer)

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 12

SIMULATION METHODS. FILLING SIMULATION.

Injection concept

Filling time [s]

Degree of filling = f(t)

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 14

SIMULATION METHODS. WARPAGE SIMULATION.

Material model according to CLT

Composite Solid elements used

Principle model

Spring-In

Simulation and

validation on real part

geometry

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 16

PROBLEM DESCRIPTION. SIMULATION ENVIRONMENT DEMANDS.

Filling simulation

Crash simulation

Iteration loops

part development and performance

Interface

2) Operative usage

Draping simulation Warpage simulation

Tool

A

Tool

B

Tool

C

Tool

D

Tool

E

Tool

F

Current design of Preforming Tool Current design of

RTM Tool

Iteration loops

feasability for manufacturing

Warpage compensation

1) Development platform

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 17

ENHANCED SIMULATION MODELS. STATE OF THE ART.

Audi [1] Metal casting

Research &

Develop

ment

2004: Louis, Zur

Simulation der

Prozesskette von

Harzinjektionsver

fahren (IVW,

Kaiserslautern)

[6]

Ind

ustr

ial a

ppl

icat

ions

Sheet metal forming Daimler [2]

Injection molding

technology

FAT [4]

RTM

process

simulation

[3]

Composite process

simulation DLR [5]

No solution on the market…

…can fully link single simulation steps

… regards all phenomena occurring in

RTM process reality

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 18

ENHANCED SIMULATION MODELS. INTERFACE CONCEPT.

fiber orientation

fiber volume fraction

part geometry

filling time

fiber volume fraction

part geometry Interface

Modular interface operations

Draping

simulation

Warpage

simulation

Filling

simulation

Classical

simulation

approach of

sequential

process

steps [6]

Additional

interface

and

modular

interface

operations Numerical modules

Phenomenological

material modules

1 1 1 1 1 1

Virtuelle CFK-Prozesskette, Markus Dix, MT-121, Juni 2014 Seite 20

PRINCIPLE PART 4XL-PROFILE. DRAPING AND RTM EXPERIMENTS.

Preforming Injection

• Diaphragma forming

• Industrialized experimental device

Material influence of industrial forming

Data aquisition

Defined forming effects close to real part

geometries

• Capability to do experiments without press

• Capability to do experiments with universal testing machine (Zwick) to measure closing force

• Experiments on warpage of CFRP parts

• Experiments on thickness and fiber volume fraction

• Flow front experiments, visualization, CFRP parts

Principle part for entire experimental process chain

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 24

Process simulation in early development phases for BMW i3 with local material properties

EXAMPLES – BMW i. STRUCTURAL PARTS 1.

Visualization of part

warpage (factor 20) of a

floor panel (BMW i3)

Filling simulation of

a side frame

structure (BMW i3)

Solver

Filling simulation

Interface

Draping simulation

Warpage simulation

Solver

Solver

Interface parameters:

• Layup

• Overall preform thickness

• Fiber volume fraction

• Permeability (2D)

• Fiber orientation (per layer)

• Material properties for target

simulation

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 25

EXAMPLES – BMW i. VIRTUAL PROCESS CHAIN.

Fiber

direction

Permeability K1/K2

Preform

thicknes

LCC 5th Anniversary Symposium, Markus Dix, 11th Sept. 2014 Page 28

• Manufacturing processes for CFRP automobile parts (e.g. RTM) are in most cases complex ones

(material, process design, …).

• The BMW Group makes use of process simulation intensively for CFRP product and process

development (draping, filling, warpage).

• A modular interface with full coupling of all RTM process steps has shown better simulation

accuracy and faster modeling tasks.

• Capabilities from commercial CAE software (e.g. ANSA) can cover most of the numerical

requirements for such an interface.

• Automation of mapping, calculation and data exchange is a key factor, which can be addressed by

scripting functionalities.

• Process simulation contributes greatly to process robustness and quality.

SUMMARY.

THANK YOU FOR YOUR ATTENTION! QUESTIONS?