Web Properties
Record of web parameters
Description
Usage
Additional Features
Parameters
The Web Properties record specifies the parameters that define the mechanics of the web and its visualization.
A Web Properties record defines the properties of all the Span components at the same or lower level. By default, all components look for a Web Properties record with the name WP1:
Models can have multiple web types. To accomplish this, where appropriate, the option Use default properties (WP1) must be unchecked, and the specific Web Properties record name entered in the provided record parameter field. Here is an example of a Nip Roller using a non-default Web Properties record with the name WP2.
The default stress/strain relationship is linear (σ=E⁢ε). Clearing the Linear check box replaces this with a nonlinear relationship defined via a lookup table.
Nonlinear Material - Variable Modulus of Elastisity
When the Use constant 'E' option is unselected, new parameters are enabled to define the modulus of elasticity as a function of strain via a lookup table.
Nonlinear Material - Variable Poisson's Ratio
When the Use constant ′ν′ option is unselected, new parameters are enabled to define the Poisson's ratio as a function of strain via a lookup table.
Include Mass (Machine Direction)
When the Include Mass (MD) option is selected, all spans in the model activate a second equation for the conservation of momentum. See Span for details.
Start at Equilibrium
When the Start at Equilibrium option is selected, upstream and downstream strain values are set to equal at initialization. In most case this results in the model starting with the web line initialized to the same tension as set at the source.
Prevent Negative Tension
When the Prevent negative tension option is selected, the stress in the span is prevented from becoming negative, however, strain can still become negative to approximately represent web accumulation. For more accurate modeling of such scenarios, use a Sagging Span component.
Visualization
When the Dynamic color option is selected, the user has the choice to have the span (and roller contact arcs) change color based on tension, velocity, width, or strain. When the web speed option is selected, the user has a choice to apply color to roller surfaces as well. This option can highlight large roller slippage.
Properties
Name
Default
Units
Modelica ID
W
1
m
Width
W_web
th
1·10−4
Thickness
th_web
ρ
1200
kgm3
Density
rho_web
Linear
true
When unchecked (false), stress/strain data is used
useLinear
C
1000
Nsm
Linear damping coefficient. Ideally, this value should be set to 1% of the linear modulus of elasticity Enabled when Use constant 'E' is unchecked (false).
C_web
E
4·109
Pa
Modulus of elasticity Enabled when Use constant 'E' is checked (true).
E_web
dr
0.01
Damping ratio [0,1] as a fraction of the variable stiffness
dr_web
ν
0.3
Poisson's ratio. Enabled when Use constant ′ν′ is unchecked (false).
nu_web
Settings
Include mass (MD)
false
When checked (true), the web inertia in the machine direction is included in the span equations.
includeMass
Start at equilibrium
When checked (true), for each span the strain is initialized to the value given by its upstream component.
start_at_equilibrium
Prevent negative tension
When checked (true), web stress is prevented from becoming negative.
prevent_negative_tension
Use constant 'E'
When unchecked (false) stress/strain data is used
Use constant ′ν′
When unchecked (false) Poisson's ratio/strain data is used
useLinear_nu
zoffset
0
Z-offset of the web centerline.
z_offset
Stress vs. Strain
Data source
inline
Data source. There are three options: 1. inline: The data is provided as a two-column matrix in the GUI. 2. file: Browse to the location where the data file is saved. 3. attachment: browse to the location where the data file is saved. The selected file is attached to the MapleSim file.
datasourcemode
σ⁡ε
[1]
[2]
table
none selected
file: Browse and select the data file. attachment: Select the attachment that contains the data set. [2]
data
Skip rows
Number of header rows to skip
skiprows
Smoothness
Linear interpolation
Selects interpolation: linear, cubic, spline, or none
smoothness
Stress unit
MPa
Unit of stress used in the data
stressUnit
Strain scale
%
Strain scale in the data
strainUnit
[1] σ⁡ε=000.140.24.50.34.6
[2] The data should have two columns; the first column is strain, the second column is stress. Each column's unit is defined separately (see Stress unit and Strain scale). Linear extrapoloation based on the last two points of the data is used if strain goes out-of-range.
Poisson's Ratio vs Strain
datasourcemode_nu
ν⁡ε
table_nu
file: Browse and select the data file. attachment: Select the attachment that contain the data set. [2]
data_nu
skiprows_nu
smoothness_nu
Strain scale in the data (% or m/m)
[1] ν⁡ε=00.30.10.30.20.20.30.2
[2] The data should have two columns; the first column is strain, the second column is Poisson's ratio values. Linear extrapoloation based on the last two points of the data is used if strain goes out-of-range.
thvis
Thickness for visualization
th_v
Transparent web
When checked (true), web is transparent
transparent_web
Use tension
When checked (true), web color is based on its calculated tension
colorMode
Web color
White
web_color
Min value color
Green
Minimum value web color
web_color1
Max value color
Red
Maximum value web color
web_color2
Roll color
Roll color. Only used in wind/unwind drums for the color of the roll
roll_color
τmin
N
Minimum Tension: color 1
minTension
τmax
Maximum Tension: color 2
maxTension
νmin
ms
minVelocity
νmax
maxVelocity
Include roller surfaces
When checked (true) roller surfaces are animated with the same color scheme as for the web speed
includeRollerSurface
ΔWmin
Minimum width reduction: color 1
minWidthReduction
ΔWmax
0.1
Maximum width reduction: color 2
maxWidthReduction
%εmin
Minimum strain: color 1
minStrainPCT
%εmax
10
Maximum strain: color 2
maxStrainPCT
εmin
minStrain
εmax
0.0025
maxStrain
ndiv
Number of segments used for web visualization
nDiv
Summary Variables
Value
Tension unit
Unit for summary variable summary_Tension
forceUnitSummary
Length unit
Unit for summary variable summary_Length
lengthUnitSummary
Wrap angle unit
degree
Unit for summary variable summary_WrapAngle
angleUnitSummary
M⋅Pa
stressUnitSummary
Strain unit
mm
strainUnitSummary
Web velocity unit
Unit for summary variables: summary_SlipVelocity, summary_WebSpeed, and summary_RollerSurfaceSpeed
slipVelUnitSummary
Roller angular velocity unit
RPM
Unit for summary variable summary_RollerAngularVelocity
angVelUnitSummary
See Also
Span
Web Handling
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