web dynamics analysis, using finite element … dynamics analysis, using finite element simulations...

Web dynamics analysis, using finite element

simulations

Dominique KNITTEL, Prof.

[email protected]

University of Strasbourg, FRANCE

2016 Aimcal Web Coating & Handling conference Europe D. KNITTEL

Outline

1. Introduction & motivation

2. 1D Model : control synthesis

3. Web dynamics and finite element modeling

Model presentation

Results

4. Conclusion

2016 Aimcal Web Coating & Handling conference Europe D. KNITTEL 2

Roll-to-Roll systems

3

• Large scale systems

• Multiphysics,

Mechatronics

• Manufacturing process

for common home

products and new

technologies

• Little waste, fast speed,

low cost production

Printed electronics Organic memories Paper printing Food packaging

Flexible solar panel printing system

Roll-to-Roll experimental plant

at Strasbourg


Common defects

4

• Strong coupling between

the different parts of the

system

• Lateral displacements

• Web properties

• Process involving

temperature, humidity,

chemical reaction

• Contact Web/rollers

• Roller shapes

Wrinkles in metal webs Wrinkles in polymer webs

Edge waves (baggy web)


Problem formulation : 1D modeling

Most models in roll-to-roll systems are one-dimensional (useful for controller adjusting/optimization):

Give the average tension in each web span and the velocity of each roller

Short simulation time

They do not take into account lateral or cross-machine effects

Assuming no slippage between web and roller

They are not able to predict/analyze web wrinkles

longitudinal web dynamics modeling : simulator in Matlab/Simulink

5

Cmotor1

T1+T2

2

T3+T4

2

Cmotor3 Cmotor5

Cfrictions1

Cfrictions5 Cfrictions3

E

R1

R3 R5 R2 R4

1 V1

V5

T1 T2 T3 T4

V3

…

5 10 15 20 25 30 35

0.5

1

1.5

2

2.5

3

Tension (daN)

T2

T1

Time (s)

0


Roll-to-Roll : control synthesis

Control : web tension, dancer position, web velocity, register

control, accumulator, ...

cascading control (torque, speed, web tension/dancer angle) measurements : dancer angle

control

6 2016 Aimcal Web Coating & Handling conference Europe D. KNITTEL

Roll-to-Roll : control synthesis

1D models : useful for the controller adjusting/optimization

Automatic synthesis of fixed order and structure controllers

(PID) :

- robustness to web elasticity variations

- effects of closed loop bandwidths

- master roller location ? (has also been studied)

Tension control (Ct : PI controller) or dancer position control

: automatically optimized with “robust control methodologies”


Roll-to-Roll : automatic optimized control

synthesis

Global system subsystem

Controller CT is automatically optimized (Matlab)

M0 : desired closed loop model (fix the tension-loop bandwidth)

Wp, Wu, Wt : frequency filters


Robust control : H∞ approach

9

in


Comparison: 1D models - 3D models

With the same controller: controller parameters calculated with

the 1D model

1D Model 3D Model


Simulations : 1D and 3D models

Comparison 1D – 3D (in closed loop : with controllers) :

Co–simulation RecurDyn – Matlab/Simulink


Simulations : 1D and 3D models

1D and 3D models:

1D model 3D model

Comparison 1D – 3D (in closed loop : with controllers):

web tension FEM Results- Lateral Stress and wrinkles

12

Cmotor1

T1+T2

2

T3+T4

2

Cmotor3 Cmotor5

Cfrictions1

Cfrictions5 Cfrictions3

E

R1

R3 R5 R2 R4

1 V1

V5

T1 T2 T3 T4

V3

…


More complex processing lines have been

studied :

processing line with lateral guide : web stresses


Model presentation : studied plant

- third roller is misaligned

- dynamics of the rollers and the web are taken into account

- the contact web/roller has to be modeled carefully


Wrinkling prediction theory


Critical angle of misalignment

from which wrinkling appears

Critical web tension from

which wrinkling appears

Lateral stress necessary to

overcome the friction force/

to create wrinkles

Results : simulation 1

- Tension: 400 N/m

- Misalignment angle: ~0 degree

- Friction ratio: 0.5

- Wrap angle: 90 degrees

- Web length/width ratio: 0.2

16

• Low average stresses value

• Uniformly distributed stresses

across the width



- Tension: 400 N/m

- Misalignment angle: 0.5 degree




17

• Low average stresses value

• Not uniformly distributed stresses

across the width



- Tension: 700 N/m

- Misalignment angle: ~0 degree




18

• medium average stresses value

• Uniformly distributed stresses

across the width



- Tension: 700 N/m

- Misalignment angle: 0.5 degree




19

• medium average stresses value

• High localized stresses (sign of

wrinkles)

• Not uniformly distributed stresses

across the width


Model presentation : studied plant

Plant at University of Strasbourg :


Results

Comparison between 1D, 2.5D and 3D models :


Results

Starting phase : velocity slippage roller 3 / web :


Decoupling : results

Web tension in different web spans (3D model) : with or without decoupling :

Web tension decoupling : subsystem (i-1) -> subsystem (i)

and subsystem (i+1) -> subsystem (i)


Roller deflection: results

Motor driven rollers

Idle rollers

In this study, we assume that one roller is flexible:


Roller deflection: higher web stress

Friction = 0.5

With one flexible

roller

Without flexible roller


Conclusion

The 1D model Advantages :

• Efficient and sufficient for a lot of applications

• Automated control synthesis

• Studies in the frequency domain

• Fast time simulations Drawbacks :

• Inaccurate web/roller contact

• Only longitudinal studies

The 3D model Advantages :

• Accurate web/roller contact

• Large possibility of studies: Complex phenomena such as wrinkles, edge waves, etc.

• Give us a lot of information about the web: state of stresses Drawbacks :

• Slow time simulations

• Need adequate tuning ( boundary conditions, elements, contact, algorithm)


Conclusion


• All rollers should be aligned

• Reduce the web tension

• It is important to reduce as much as possible the web/roller friction coefficient

• The need of well tuned lateral guides (has to be aligned in steady state)

Other studies :

• Modeling, analysis and control of complex industrial roll-to-roll plants

(confidential works)

• Effects of other parameters : roller shapes, not uniform web thickness, not

uniform Young’s modulus, ....

web dynamics analysis, using finite element … dynamics analysis, using finite element simulations...

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