PTS research activities related to COST FP 1005
Simulation of micro structure mechanics in dynamic fibre networks
Timo Kuntzsch, Jan Matheas, Sven Altmann
2
Competencies of PTS – all under one roof
Scientific methods
• Design & Simulation
• Sensorics
• Analytics
Value chain
… – wood – paper – converting – …
Surface finishing
Material testing and
expert opinions
Innovative
fibre composites
Environmental relevance and
sustainability aspects
Efficient use of
resources
Scientific methods
Education and training
08.04.2015
 PTS 2011
3
Design & Simulation – Focal Points
Development of methods and tools for
numerical simulation of paper properties
L
H
Transition from micro- to final product properties
d
D
d
• micro structure generation
• micro structure mechanics simulation
• homogenisation methods
Simulation based optimisation of the paper
production process considering material and
economical criteria
70
60
Kosten in €/tPapier
50
Investitionen
Entsorgung
Chemikalien
Energie
Rohstoffe
40
20
10
0
VS
55%
25KW
Fraktionierung
3,2
55% 50KW
24,9
100%
100%
SZ_7
30%
50KW
2,3
SZ_4opt
30%
25KW
1,5
SZ_4.2.2
SZ_3.2.2
10%
10%
30%
30%
30%
50KW 100KW 50KW 100KW 25KW
1,5
SZ_4.2.1
SZ_3.2.1
1,1
SZ_3opt
55,6
SZ_6.1
100%
DAF
54,6
SZ_5.1
50%
18,3
SZ_4.1.2
40% 4.02
18,0
SZ_4.1.1
nur
4.01
Altpapier
1,4
SZ_3.1.2
nur
1.04
0,7
SZ_2.2
nur
1.02
5,8
SZ_3.1.1
IST
8,3
SZ_2.1
-1,4
-7,2
SZ_1opt
• PTS-SoftMcNett
0,0
SZ_1.2
-20
SZ_1.4
-10
SZ_0
• PTS-ProductOptimizer
30
SZ_1.1
Maintenance of comprehensive pulp property data base
SZ_1.3
Linkage of pulp characteristic, process parameters, paper
properties and calculation of costs
Flotation Wäsche Kombi
Szenarien
08.04.2015
 PTS 2011
Micro structure simulation – fibre network generation
4
Making available digital models of single fibres, fibre bonds and fibre networks
Fibre arrangement and accumulation
• Size of modelled section (x-y-plane)
• Fibre number (~g/m²), morphology, size distribution
• Fibre orientation distribution und x-y-arrangement
• Fibre shape profiles in Z-direction after sheet forming
• Adjustment of sheet thickness and apparent density
by pressing process simulation
Subsequent modelling of:
• Behaviour under mechanical load
• Capillary force driven liquid penetration
• Optical properties
Comparison of different model approaches
e.g. shell vs. beam elements
08.04.2015
fibre network e.g. 2 x 2 x 0,1 mm³
 PTS 2011
Micro structure mechanics simulation
5
Finite element model of fibre bond mechanics
• Size and shape of bonding areas
• Mechanical characteristics of fibre bond and
fibre wall materials (deformation, failure)
Model of fibre network mechanics
• Search algorithm for contact sites
• Implementation of fibre bond model
• Modelling the behaviour under mechanical
load (e.g. tensile testing)
• Deduction of a homogenised material model
08.04.2015
 PTS 2011
6
Example: numerical simulation of tensile testing
a) Numerically created paper fibre network (area 1mm², height 0.09, sheet density 0.6g/cm³)
b) Mechanical model of the fibre network; centre fibre line, idealised fibre bonds)
c) longitudinal fibre forces (network is stretched by 2% in x-direction; tension; pressure)
d) bonding forces of idealised fibre bonds in the stretched network
08.04.2015
 PTS 2011
7
Expected benefit from COST FP 1005
Micro structure simulation in fibre networks requires insight in dynamic processes
during sheet forming  largely determined by pulp suspension fluid dynamics
• more realistic and verified micro structure models for improved fibre network
mechanics simulation
• Improved characterisation of physical processes during sheet forming, pressing, and
drying, thus more realistic paper and fibre network properties
Elucidation of interactions between fibre properties (surface structure, flexibility,
morphology …) and suspension flow characteristics
• Effect of fibre modification on pulp suspension flow characteristics
• Impact of fluid dynamics on fibre properties during stock preparation treatment
• Influence of pulp suspension flow parameters on resulting fibre network properties
08.04.2015
 PTS 2011
8
Expertise to bring in to COST FP 1005
• modelling and simulation of paper properties and processes, micro structure
simulation, mechanics of fibre networks
• optimal use and modification of fibres for different processes and products, fibre
and fibre network characterization (e.g. fibre morphology distribution …)
• experimental investigations under conditions very similar to processes in paper
mills using the pilot scale paper machine (stock preparation, sheet forming)
• linking fundamental research to applied research activities
08.04.2015
 PTS 2011