Flexible Beam
A flexible beam with axial, lateral, and torsional deformations
Description
Connections
Parameters
See Also
A Flexible Beam is shown schematically in the diagram below. Each flexible beam has three associated frames: a primary reference frame, framea (the gray frame in the diagram), an end frame, frameb, and a reference frame, base. Beam deformations are then measured with respect to the framea. When undeformed, the beam is straight and its neutral axis is aligned with the x axis of the framea. The Rayleigh beam model includes axial deformation along the neutral axis, bending about both the y and z axes, and torsional deformations about the x axis.
The beam material is assumed to be linearly elastic, that is, the stress tensor is a linear function of the strain tensor.
The Flexible Beam component can represent beams with multiple sections having different cross-sections and different material properties. It is also possible to specify the cross-section area properties by selecting a shape from a list of predefined shapes. The following shapes are available: Circle, Hexagon, I-beam, and Rectangle.
The base frame is used only with the Flexible Beam Frame component as shown in the following figure. Any number of Flexible Beam Frame components can be connected to the base frame to define additional frames on the flexible beam.
Name
framea
Base of flexible beam (inboard frame)
frameb
Tip of flexible beam (outboard frame)
base
Special port for connecting Flexible Beam Frames
Geometry
Symbol
Default
Units
Modelica ID
Use multiple sections
When selected, the parameter L becomes a vector (list) of shaft section lengths from frame_a to frame_b
useMultiSection
L
1
or
0.5, 0.5
m
Beam length. This is either a single value or a vector of values, with each vector element representing the length of a beam section. The vector option is available when you select the Use multiple sections option.
Note: When undeformed, the beam is straight and its neutral axis is aligned with the x axis of the framea.
L_s
L_v
Use Predefined Shape
When selected the cross-section area properties are defined using a predefined shape (See section description for the available options)
useShape
section
CircleHexagonI-beamRectangle
Select a predefined section. Select Use Predefined Shape to enable this option.
Available options: Circle, Rectangle, Hexagon, and I-beam.
sectionType
Properties for Default and Predefined Shapes
A
0.001
0.001, 0.002
m2
Beam cross-sectional area. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
A_g_s
A_g_v
dly
2⋅10−7
2⋅10−7, 2. 5⋅10−7
m4
Second moment of the cross-sectional area about the y axis. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
dIy_g_s
dIy_g_v
dlz
Second moment of the cross-sectional area about the z axis. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
dIz_g_s
dIz_g_v
Circle
R__o
0.01
0.01,0.02
Outer radius. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
Ro_s
Ro_v
R__i
0
0,0
Inner radius. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
Ri_s
Ri_v
Rectangle
b
0.1
0.1,0.12
Width. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
b_s
b_v
h
0.2
0.2,0.25
Height. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
h_s
h_v
b__i
Inner width. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
bi_s
bi_v
h__i
Inner height. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
hi_s
hi_v
Hexagon
a
0.01,0.01
Side length. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
a_s
a_v
I-beam
t__1
Flange thickness. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
t1_s
t1_v
t__2
Web thickness. This is either a single value or a vector of values for each section of the beam (that is, Use multiple sections is selected). The vector must have the same number of elements as L.
t2_s
t2_v
Material
Use single material
Only available when you select Use multiple sections. When selected, material parameters are single values (that is, the beam is uniform). When cleared, material parameters are vectors (lists), and each element in the vector is the material property value for that section of the beam.
useSameMaterial
ρ
3000
3000,3000
kgm3
Beam density. This is either a single value or a vector of values. The vector is available when you select Use multiple sections and clear Use single material. The vector must have the same number of elements as L.
rho_s
rho_v
E
7⋅1010
7⋅1010,7⋅1010
Pa
Young's modulus of elasticity. This is either a single value or a vector of values. The vector is available when you select Use multiple sections and clear Use single material. The vector must have the same number of elements as L.
E_s
E_v
E*/E
s
Bending/Elongation damping as a proportion of Young's modulus of elasticity. This is either a single value or a vector of values. The vector is available when you select Use multiple sections and clear Use single material. The vector must have the same number of elements as L.
cE_s
cE_v
G
2.7⋅1010
2.7⋅1010,2.7⋅1010
Nm2
Shear modulus of elasticity. This is either a single value or a vector of values. The vector is available when you select Use multiple sections and clear Use single material. The vector must have the same number of elements as L.
G_s
G_v
G*/G
Torsional damping as a proportion of shear modulus of elasticity. This is either a single value or a vector of values. The vector is available when you select Use multiple sections and clear Use single material. The vector must have the same number of elements as L.
cG_s
cG_v
Formulation
ECx
Number of elastic coordinates for axial deformation along the x axis
Axial
ECy
Number of elastic coordinates for lateral deformation along the y axis
LateralY
ECz
Number of elastic coordinates for lateral deformation along the z axis
LateralZ
ECφ
Number of elastic coordinates for torsional deformation about the x axis
Torsional
Advanced
Straight
Strictly Enforce
Indicates whether MapleSim ignores, tries to enforce, or strictly enforces a straight beam at the start of the simulation
ElasticICs
ICf,v
Ignore
Indicates whether MapleSim ignores, tries to enforce, or strictly enforces the translational initial conditions
MechTranTree
r&conjugate0;0
000
Initial displacement of the inboard frame at the start of the simulation, expressed along the x-, y-, and z-axis of the inboard frame respectively
InitPos
Typev
Inboard
Indicates whether the initial velocity is expressed in the inboard or outboard frame
VelType
v&conjugate0;0
ms
Initial velocity of the inboard frame frame at the start of the simulation, expressed along the x-, y-, and z-axis of the inboard frame respectively
InitVel
ICθ,ω
Indicates whether MapleSim ignores, tries to enforce, or strictly enforces the rotational initial conditions
MechRotTree
Typeθ
123
Indicates the sequence of body-fixed rotations used to describe the initial orientation of the center of mass frame. For example, 1,2,3 refers to sequential rotations about the x, then y, and then z axis (123 - Euler angles).
RotType
θ&conjugate0;0
rad
Initial rotation of the inboard frame at the start of the simulation, based on the Typeθ parameter value
InitAng
Typeω
Euler
Indicates whether the initial angular velocity is expressed in the inboard or outboard frame. If Euler is selected, the initial angular velocities are assumed to be the direct derivatives of the Euler angles.
AngVelType
ω&conjugate0;0
rads
Initial angular velocity of the inboard frame at the start of the simulation, based on the Typeω parameter value
InitAngVel
Shape
Taylor
Polynomial shape function
ShapeFunc
TruncI
Truncation order of inertial terms
ITrunc
TruncEC
Truncation order of elastic coordinates
ETrunc
Visualization
Show visualization
false
True means geometry is visible in playback
showVisualization
Dvis
Diameter of cylindrical visualization (segment cross section changes are ignored)
n
3
Maximum number of pieces (per segment)
np
Color
Color of the sphere
Transparent
Radius
Bodies and Frames
Flexible Beam Frame
Multibody Overview
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