Sammelmappe2

Chapter 5 3D Simulations 1

Chapter 53D Simulations5.1 Step-by-Step: Beam Bracket

5.2 Step-by-Step: Cover of Pressure Cylinder

5.3 More Details

5.4 More Exercise: LCD Display Support

5.5 Review

Chapter 5 3D Simulations Section 5.1 Beam Bracket 2

Section 5.1Beam Bracket

Problem Description

[1] The bracket is made of

structural steel.

[2] The bracket is designed to

withstand a load of 27 kN uniformly distributed over

the seat plate.

[3] Fixed support at the back

face.

Chapter 5 3D Simulations Section 5.1 Beam Bracket 3

Techniques/Concepts

• Engineering Data

• Material Assignment

• Stress Tool>Safety Factor

• Structural Error

• Mesh Control>MultiZone

• 3D Solid Elements

Chapter 5 3D Simulations Section 5.2 Cover of Pressure Cylinder 4

Section 5.2Cover of Pressure Cylinder

Problem Description

[3] Circularity of this internal

surface is what concerns us most.

[1] The cover is made of an engineering

plastic.

[2] The cover is designed to hold

up an internal pressure of 0.5

MPa.

Chapter 5 3D Simulations Section 5.2 Cover of Pressure Cylinder 5

Techniques/Concepts

• Add a new material in

<Engineering Data>

• Isotropic Elasticity

• Material Assignment

• Loads>Pressure

• Create a new coordinate

system

• Cylindrical Coordinate

Systems

Chapter 5 3D Simulations Section 5.3 More Details 6

Global Mesh Controls

• Relevance Center

• Relevance

• Number of nodes/elements

• Mesh Quality Metric

Section 5.3More Details


Mesh with MultiZone Method

• Generally, hexahedral elements are more

desirable than tetrahedral.

• A simple idea of creating hexahedra is to

mesh faces (source) of a body with

quadrilaterals and then "sweep" along a path

up to other end faces (target) of the body.

• Not all bodies are sweepable.

• The idea of <MultiZone> method is to

decompose a non-sweepable body into

several sweepable bodies, and then apply

<Sweep> method on each of bodies.


Coordinate Systems

• When defining an environment

condition or a solution object by

<Components>, you need to refer

to a coordinate system. By default,

<Global Coordinate System> is

used, which is a Cartesian

coordinate system.

• To define a new coordinate

system, you need to define the

type of the coordinate system, the

origin, and the axes.

[1] Type of the coordinate

system.

[2] Origin.

[3] Axes.


[1] Increase/decrease contour

bands.

[4] Number of significant digits.

[3] Double-click to edit value.

[5] Turn on/off the date/time.

[6] Display independent

bands.

[2] The divider can be dragged.

[7] Reset the legend.

Legend Controls


Adaptive Meshing

• Workbench provides a tool to

automate the mesh refinement

until a user-specified level of

accuracy is reached.

• This idea is termed adaptive

meshing.

• Internally, Workbench exploits

the structural errors to help

adjust the mesh, that is, it refines

the mesh size in the area of

large structural errors.

Chapter 5 3D Simulations Section 5.4 LCD Display Support 11

Section 5.4LCD Display Support

Problem Description [2] The design load (40 N) applies on

the trough.

[1] The LCD display support is made of an ABS

plastic.

Chapter 5 3D Simulations Section 5.4 LCD Display Support 12

Techniques/Concepts

• Loads>Bearing Load

Chapter 6 Surface Models 1

Chapter 6Surface Models6.1 Step-by-Step: Bellows Joints

6.2 Step-by-Step: Beam Bracket

6.3 More Exercise: Gearbox

6.4 Review

Chapter 6 Surface Models Section 6.1 Bellows Joints 2

Section 6.1Bellows Joints

Problem Description

• With the internal pressure, the

engineers are concerned about the

radial deformation (due to an

engineering tolerance

consideration) and hoop stress

(due to a safety consideration).


R315

28

R315 28

20

Unit: mm.


Techniques/Concepts

• Create surface bodies

using <Revolve>.

• Top/Bottom of a surface

body

• Shell Elements

Chapter 6 Surface Models Section 6.2 Beam Bracket 5

Section 6.2Beam Bracket

Techniques/Concepts

• Create surface bodies

using <Mid-Surface>

Chapter 6 Surface Models Section 6.3 Gearbox 6

Section 6.3Gearbox

Problem Description

[3] The housing is made of

stainless sheet steel of 3 mm

thickness.

[1] The flanged bearing is made of gray cast iron.

[2] The base is also made of cast

iron.


Unit: mm.

540

520

240

180

100

355

15 3

0

170 R30

R50 R20

R40

170 200 70

(R170)

(R70)


Techniques/Concepts

• Create surface bodies by

<Thin/Surface>

• Loads>Bearing Loads

• Set up <Bonded>

connections.

Chapter 7 Line Models 1

Chapter 7Line Models7.1 Step-by-Step: Flexible Gripper

7.2 Step-by-Step: 3D Truss

7.3 More Exercise: Two-Story Building

7.4 Review

Chapter 7 Line Models Section 7.1 Flexible Gripper 2

Section 7.1Flexible Gripper

Problem Description

[3] Actuation direction (input).

[2] The ends are connected to a rigid ground (preventing

translations and rotations).

[4] Gripping direction (output).

[1] The gripper is made of POM.

P1(−70,0)

P2(−90,40)

P3(−69,120)

P4(−35,160)

P5(−34,100)

P6(−24,60)

P7(0,50)

X

Y


Techniques/Concepts

• Line bodies

• Cross Sections

• Cross Section Alignments

• Cross Section Solids

• Beam Elements

• Symmetry Conditions

• Geometric Advantage

0

10

20

30

40

50

60

0 5 10 15 20 25 30 35 40 45 50

Hor

izon

tal D

ispl

acem

ent

(mm

)

Input Displacement (mm)


52.24

52.26

52.28

52.30

52.32

0 125 250 375 500 625

Out

put

Dis

plac

emen

t (m

m)

Number of Elements

Convergence Study of Beam Elements

[1] In this exercise, we meshed with 34

elements, resulting 52.335 mm of displacement.

[2] The displacement converges to 52.381 mm.

Chapter 7 Line Models Section 7.2 3D Truss 5

200"

200"

75"

P1 P2

P3

P4

P5 P6

P7 P8

P9 P10

1

2

3 4

5 6 7 8 9

10 11

12 13

14 15

16

17

18 19

20

21

22 23

24

25

100

" 10

0"

X Y

Z

75"

Section 7.23D Truss

Problem Description

Design Loads for the Transmission Tower

Joint FX (lb) FY (lb) FZ (lb)

P1 1,000 -10,000 -10,000

P2 0 -10,000 -10,000

P3 500 0 0

P6 600 0 0

Chapter 7 Line Models Section 7.2 3D Truss 6

Techniques/Concepts

• Create points

• Concepts>Lines From Points

• Convergence of straight beam

elements

Chapter 7 Line Models Section 7.3 Two-Story Building 7

Section 7.3Two-Story Building

Problem Description

[1] All beams and columns are made of structural steel,

with a cross section of W16x50. [2] The floor slabs

are made of reinforced concrete, with a thickness of 5".

[3] Each floor-to-floor height is 10'.

20

'

20 ' 20 ' 20 '

Chapter 7 Line Models Section 7.3 Two-Story Building 8

Techniques/Concepts

• Adjust Cross Section

Alignments

• Concepts>Surface From

Edges

• Use of Selection Panes

• Flip Surface Normal

• Form New Part

• Import Engineering Data

• Inertial>Standard Earth

Gravity

• Inertial>Acceleration

Chapter 8 Optimization� � 1

Chapter 8Optimization8.1� Step-by-Step: Flexible Gripper

8.2� More Exercise: Triangular Plate

8.3� Review

Chapter 8 Optimization� Section 8.1 Flexible Gripper� 2

Section 8.1Flexible Gripper

Problem Description

P1(�70,0)

P2(�90,40)

P3(�69,120)

P4(�35,160)

P5(�34,100)

P6(�24,60)

P7(0,50)

X

Y

• Positions of the P2, P3, and P6 are free to be changed.

• The idea is to fix the X-coordinates of these points and

adjust their Y-coordinates to achieve a better GA value.

• Allowable adjustment ranges are 10 mm for P2, 20 mm

for P3, and 5 mm for P6.

• The maximum stress should not exceed 15 MPa.

Chapter 8 Optimization� Section 8.1 Flexible Gripper� 3

Techniques/Concepts

• Input Parameters

• Output Parameters

• Design Points

• Goal Driven Optimization

• Design of Experiments

• DOE Tables

• Response Surfaces

• Optimization

• Objectives and Constraints

• Optimization algorithms

• Current Design

Chapter 8 Optimization� Section 8.2 Triangular Plate� 4

Section 8.2Triangular Plate

Problem Description

W

R

[2] The initial value of the width of the

bridge is 30 mm and its allowable range is

20-30 mm.

[3] The initial value of the radius of the fillet is 10 mm and its allowable range is

5-15 mm.

[1] we want to change the values

of W and R to reduce the amount

of material.

Chapter 8 Optimization� Section 8.2 Triangular Plate� 5

Techniques/Concepts

• No additional techniques/concepts are introduced.

Chapter 9 Meshing 1

Chapter 9Meshing9.1 Step-by-Step: Pneumatic Fingers

9.2 More Exercise: Cover of Pressure Cylinder

9.3 More Exercise: Convergence Study of 3D Solid Elements

9.4 Review

Chapter 9 Meshing Section 9.1 Pneumatic Fingers 2

Section 9.1Pneumatic Fingers

Problem Description

Unit: mm.

80

5

1 2

5.1 4

3 3.2 1 (19.2)

Plane of symmetry.

Chapter 9 Meshing Section 9.1 Pneumatic Fingers 3

Techniques/Concepts

• Mesh Metric: Skewness

• Hex Dominant Method

• Sweep Method

• MultiZone Method

• Section View

• Nonlinear Simulations

• Line Search

• Displacement Convergence

Chapter 9 Meshing Section 9.2 Cover of Pressure Cylinder 4

Section 9.2Cover of Pressure Cylinder

Techniques/Concepts

• Patch Conforming Method

• Patch Independent Method

Chapter 9 Meshing Section 9.3 Convergence Study of 3D Solid Elements 5

Section 9.3Convergence Study of 3D Solid Elements

Problem Description

100 mm

10 mm

[1] The beam is made of steel.

[2] The width of the beam is 10 mm. A uniform load of 1 MPa applies on the upper face of the beam.

[3] We will record the vertical tip deflection.


Element Shapes

[1] hexahedron. [2] Tetrahedron.

[4] Perpendicular prism.

[3] Parallel prism.


0.60

0.64

0.68

0.72

0.76

0 3000 6000 9000 12000 15000

Tip

Def

lect

ion

(mm

)

Number of Nodes

Lower-Order Elements

[1] Lower-order tetrahedron.

[2] Lower-order perpendicular

prism.

[3] Lower-order parallel prism.

[4] Lower-order hexahedron.


0.746

0.747

0.748

0.749

0.750

0.751

0.752

0 2000 4000 6000 8000 10000

Tip

Def

lect

ion

(mm

)

Number of Nodes

Higher-Order Elements

[1] Higher-order tetrahedron.

[2] Higher-order perpendicular prism.

[3] Higher-order parallel prism.

[4] Higher-order hexahedron.


0.746

0.747

0.748

0.749

0.750

0.751

0.752

0 2000 4000 6000 8000 10000

Tip

Def

lect

ion

(mm

)

Number of Nodes

Hexahedra

[2] Higher-order hexahedron.

[1] Lower-order hexahedron.


0.600

0.640

0.680

0.720

0.760

0 2000 4000 6000 8000 10000

Tip

Def

lect

ion

(mm

)

Number of Nodes

Tetrahedra

[1] Lower-order tetrahedron.

[2] Higher-order tetrahedron.


0.66

0.68

0.70

0.72

0.74

0.76

0 2000 4000 6000 8000 10000

Tip

Def

lect

ion

(mm

)

Number of Nodes

Parallel Prisms

[2] Higher-order parallel prism.

[1] Lower-order parallel prism.


0.66

0.68

0.70

0.72

0.74

0.76

0 2000 4000 6000 8000 10000

Tip

Def

lect

ion

(mm

)

Number of Nodes

Perpendicular Prisms

[2] Higher-order perpendicular prism.

[1] Lower-order perpendicular prism.


Guidelines

• Never use lower-order tetrahedra/triangles.

• Higher-order tetrahedra/triangles can be as good as other elements as long as the

mesh is fine enough. In cases of coarse mesh, however, they perform poorly and

are not recommended.

• Lower-order prisms are not recommended.

• Lower-order hexahedra/quadrilaterals can be used, but they are not as efficient as

their higher-order counterparts.

• Higher-order hexahedra, prisms, and quadrilaterals are among the most efficient

elements so far we have discussed. Mesh your models with these elements

whenever possible. If that is not possible, then at least try to achieve a higher-

order hexahedra-dominant or quadrilateral-dominant mesh.

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