Chapter 1: An Introduction to Inventor Simulation ppt

CHAPTER 1
An Introduction to Inventor Simulation
In Dynamic Simulation, we divide time into smaller segments also referred to as images.
chúng ta chia thời gian thành các đoạn nhỏ hơn cũng được gọi là hình ảnh
We calculate the dynamic equilibrium ( cân bằng ) of the mechanism ( cơ chế ) at each time step.
M A F
M mass matrix
A articular accelerations
F external forces
Simulation workfl ow
The process( quá trình ) of creating a Dynamic Simulation study involves four core steps.
Step 1
Step 2
Step 3
Step 4
GROUP together all components and assemblies with
no relative ( tương đối ) motion between them
CREATE JOINTS between components that have
relative motion between them
CREATE ENVIRONMENTAL CONDITIONS(diều kien)
to simulate reality
ANALYZE RESULTS
Phân tích kết quả
3
STEP 1 : There are two options to group components together, and both have their advantages and
disadvantages.
Option 1 – Create subassemblies within the assembly environment.
Disadvantage – Restructuring(Tổ chức lại) your subassembly will affect ảhg your BOM database, hence you
may need to create a duplicate for simulation purposes.
Option 2 – Weld components together within Simulation environment.
Advantage – This method will not alter your BOM database.

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CHAPTER 1
An Introduction to Inventor Simulation
STEP 2 : The process of creating joints can be broken down into two stages.
Stage 1 – Create Standard Joints.
Stage 2 – Create Nonstandard Joints.
Stage 1 – There are three options to create Standard Joints, and again, each has its own advantages
and disadvantages.
Option 1 – Use Automatic Convert Constraints to Standard Joints.
Advantage – This is by far the quickest way to create joints.
Disadvantages
– Can be tedious to go through all joints converted for a large assembly.
– Cannot repair redundancies within the Simulation environment.
– Cannot create Standard Joints within the Simulation environment, with the exception of
Spatial joint.
Option 2 – Use Manual Convert Assembly Constraints.
Advantages
– You can manipulate the type of joint created from constraints.
– You can create Standard Joints within the Simulation environment.
– You can repair redundancies for all Standard Joints not created from constraints.
Disadvantage – This method is slower than option 1.
Option 3 – Create Standard Joints from scratch.
Advantages
– You have complete control over how Standard Joints are created.
– You can repair redundancies for all Standard Joints created.
Disadvantage
– This method is the slowest.
– Does not make use of the assembly constraints.
Stage 2 – Comprises of creating Nonstandard Joints that do not make use of assembly constraints and
includes the following types of Joints.

– Rolling
– Sliding
– 2D Contact
– Force
Note : Rolling Joints for Spur Gears, designed using Design Accelerator, can be created automatically.
STEP 3 : Once the appropriate joints have been created, the next step is to simulate reality. This can be
achieved by applying any of the following.
– Joints – Defi ne starting position.
– Joints – Apply friction to joints.
– Forces/Torque – Apply external loads.
– Imposed motion on predefi ned joints.
• Position, Velocity Acceleration (Constant values).
• Input Grapher – Create Specifi c Motions (Nonconstant values).
STEP 4 : This is the fi nal step in which you use the Output Grapher to analyze results in joints, including
– Positions/ Velocity/Acceleration
– Reaction Forces
– Reaction Torque
– Reaction Moments
– Contact Forces
CHAPTER 1
An Introduction to Inventor Simulation
The most time-consuming process when creating a Dynamic Simulation study is Step 2 –
creating joints that can be greatly affected by Step 1 – grouping components. With this in
mind, I suggest you take the following approach when creating joints.
OPTIMIZED WORKFLOW FOR CREATING JOINTS
GROUP COMPONENTS/SUBASSEMBLIES
Are you
concerned by
altering the BOM
No

Restructure components into sub-
assemblies environment within the
Assembly environment
CREATE JOINTS AUTOMATICALLY
Yes
Weld component and
subassemblies within the
Simulation environment
5
Activate the Dynamic Simulation
Environment if not already activated
In the Dynamic Simulation Settings dialog box activate
Automatically Convert Constraints To Joints
Activate Assembly Constraints dialog box by
pressing C. Start Creating Assembly constraints
Modify assembly constraints to remove redundancies in Standard Joints
e.g. change Line–Line constraint to Point–Line constraint; this will
change cylindrical joint to Point–Line joint releasing 2 degrees of freedom
Start creating Non-Standard Joints manually
e.g. Rolling, Sliding, 2D Contact, and Force Joints
6
CHƯƠNG 1
Giới thiệu về mô phỏng Inventor
Mô phỏng giao diện người dung
Mô phỏng động có thể truy cập trong môi trường lắp ráp theo đường dẫn Tab
1. Trình duyệt mô phỏng động
2. Cửa sổ mô phỏng động
3. Bảng mô phỏng động
4. Chạy mô phỏng động
BẢNG MÔ PHỎNG ĐỘNG

Thanh mô phỏng động Quá trình làm việc Mô tả
CHƯƠNG 1
Giới thiệu về mô phỏng Inventor
Bước 2
Bước 3
Bước 4
Bước 5
Bước 6
Chèn khớp – Tạo ra tiêu chuẩn và khớp chuẩn
Chuyển đổi rang buộc – Tạo ra tiêu chuẩn Khớp đến
sự lựa chọn trong rang buộc lắp ráp giữa
hai thành phần
Tình trạng cơ chế –dùng để xác định sự di động và
and cơ chế dư của lắp ráp bao gồm sửa chữa phần
dư thừa trong khớp
Lực – áp dụng lực bên ngoài lên một thành phần.
Moomen xoắn – áp dụng moomen xoắn
lên thành phần.
Kết quả biểu đồ–Dùng để phân tích khớp bao
gồm cả vị trí, vận tốc và gia tốc.
Sự chuyển động– cho phép người sử dụng kiểm tra
mô hình trước khi chạy mô phỏng toàn bộ.
Lực ẩn – dùng để xác định lực, mômen,
và lực cưởng bức Điều kiện mô phỏng.
Dấu hiệu – Dùng dấu hiệu để tính toán và đầu ra
vị trí của từng thành phần , khớp trong đầu
ra biểu đồ bao gồm vị trí, vận tốc và gia tốc
Chuyển đổi đến FEA – Toàn bộ khả năng di chuyển
Phản lực tải đến khi căn môi trường phân tích
Xuất bản phim– bạn có thể cho ra chuyển động

của file video.
Xuấ ra Studio – You can output your
motion to inventor studio for producing
cao trả lại những hoạt cảnh/
Sự thiết đặt Mô phỏng Cung cấp Vài.
những tùy chọn người sử dụng.
Người chơi Mô phỏng Cung cấp những
công cụ để chơi. sự mô phỏng
Tham số - Bảng những Tham số
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CHAPTER 1
Giới thiệu về mô phỏng Inventor
CHƠI MÔ PHỎNG
1. Construction Mode – Sau khi sự mô phỏng Có Nished, kiểu xây dựng. cần được chọn để tiếp tục soạn thảo sự mô
phỏng.
2. Final Time – Chỉ rõ thờI gian của sự mô phỏng.
3. Simulation Time – Chỉ đọc giá trị các bước bước diễn trong thờI gian mo phỏng.
4. Percentage of realized simulation – Đọc các giá trị trình bày phần trăm của mô phỏng hoàn thành.
5. Real Time – Chỉ đọc giá trị hiển thị thời gian trôi qua trong quá trình mô phỏng thực tế.
6. Filter (lọc) – Thông thường thiết lập để 1. Có thể được thay đổi đến một giá trị khác ngoài 1; nếu đặt
10, các mô phỏng sẽ bỏ qua tất cả các hình ảnh từ 1 đến 10 trong mô phỏng phát lại.
7. Continuous Playback of simulation.( Phát liên tục mô phỏng)
8. Advances to end of simulation. Tiến tới kết thúc của sự mô phỏng.
9. Deactivate screen refresh at each time step – Ngăn chặn việc làm mới màn hình ở mỗi
bước thời gian, mà có thể giúp tăng tốc độ mô phỏng.
10. Play simulation. Chơi mô phỏng
11. Stop simulation.
12. Rewind simulation to beginning. Cuốn lại sự mô phỏng để bắt đầu

13. Images – Bình thường là bậc cao Số Chính xác hơn Sự mô phỏng;.
Tuy nhiên, sự mô phỏng sẽ cầm dài hơn để chạy
Thiết lập mô phỏng
CHAPTER 1
Giới thiệu mô phỏng trong Inventor
9
1. Automatically Convert Constraint to Joint Nếu đánh dấu sẽ chuyển đổi tất cả các lắp ráp rang buộc đến tiêu chuẩn và
lăn khớp để thúc đẩy bánh răng duy nhất, nếu được thiết kế bằng cách sử dụng thiết kế máy gia tốc
2. Warning –Khi lắp ráp không vững các khớp, một cảnh báo sẽ được hiển thị
3. Color Mobile Groups – Gán một màu được xác định trước cho từng thành phần điện thoại di động
và / hoặc subassembly
4. AIP Stress Analysis – Sẽ chuyển tải phản ứng với stress tích Inventor môi trường
5. ANSYS Simulation – Chuẩn bị một tập tin với tất cả các kết quả tải cho ANSYS DesignSpace.
6. Location of FEA File – Đây là nơi chứa file dữ liệu tải được lưu.
7. Set Initial Positions – tập hợp tất cả vị trí đến 0.
8. Reset Joint Positions – Khởi động lại toàn bộ các vị trí của khớp tại vị trí góc của nó.
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CHAPTER 1
GiớI thiệu về mô phỏng Inventor
Thiết lập mô phỏng nhiều hơn
1. Display a copyright in AVIs – Hiển thị các thông tin bạn chỉ định tạo ra AVI
2. Input angular velocity (rpm) – Khi được chọn sẽ cho phép bạn xác định tốc độ đầu vào
trong vòng / phút
3. 3D frames – Thiết lập độ dài của trục Z lắp ráp trong cửa sổ đồ họa.
4. Micro-Mechanism Model – Lựa chọn này khi khối lượng hoặc quán tính lớn hơn
1e-20 kg và 1e-32 kg.m2 chẳng hạn như cho phép bạn làm việc với các mô hình cơ chế vi sinh.
5. Assembly Precision – Cho phép thiết lập khoảng cách tối đa giữa hai điểm tiếp xúc
Điều này chỉ áp dụng cho 2D liên hệ và các vòng khép kín.
6. Solver Precision – Năng động, phương trình được tích hợp bằng cách sử dụng một năm để Runge-Kutta

Đề án hội nhập.
7. Capture Velocity - Đây là cú sốc đối với va chạm và cho phép bạn giới hạn số bị trả lại nhỏ trước khi kết quả liên lạc
thường xuyên. Giá trị có thể được qui định giữa 0 và 1, với 0 là tối đa năng lượng tiêu tán.
8. Regularization Velocity – Tiếp xúc 2D, thực vi tuyến định luật ma sát là dùng, và tiếp xúc 3D theo một nguyên tắc định
luật sử dụng , để tránh siêu tĩnh.

SỰ ĂN KHỚP
Đây có lẽ điều quan trọng nhất của vẻ bề ngoài tạo ra thiết lặp mô phỏng và sẽ thảo luận về sau :
1. Các loại khớp
2. Các khớp ma trận – Một ảnh chụp các khớp được dùng trong sách
3. Qui trình tạo khớp
4. Khớp dự phòng
CHAPTER 1
Giới thiệu mô phỏng về Inventor
Các kiểu khớp
Mô phỏng động, Là năm loại khớp nối, bao gồm tiêu chuẩn ,lăn, trượt, lien kết 2D và lực khớp nối
.Chúng ta sẽ thảo luận chi tiết trong các phần sau.
TIÊU CHUẨN CÁC KHỚP
Mô phỏng động các khớp
Sự xoay
– không trượt
– Quay quanh trục Z
Bảng
– Trượt dài trên trục Z
– Không quay
Trụ
– Trượt trên trục Z
– Quay quanh trục Z
Spherical
– No translation

– Rotation around all axes
Planar
– Translation along X and Z axes
– Rotation about Y axis
Point-Line
– Translation along Z axis
– Rotation around all axes
Line-Plane
– Translation along X and Z axes
– Rotation about Y axis
Point-Plane
– Translation along X and Z axes
– Rotation about all axes
Spatial (không gian )
– Translation along all axes
– Rotation about all axes
Welding
– No translation
– No rotation

Lắp ráp tương đương
Ràn buộc
Chèn
or
Trục – trục điểm – điểm
Mặt – mặt trục -trục
Trục và trục
or
biên và biên
điểm - điểm

mặt và mặt
or
Tuôn ra và tuôn ra
Point and Edge
(or axis)
Face and Edge (mặt và mép )
(or axis)
Face and Point
(also tangent constraint)
Unconstrained
( khoogn bi bắt buộc )
Fully constrained,
that is, no DOF
between components
DOF of
joints
1
1
2
3
2
4
3
4
6
0
11
Standard joints can be automatically converted from assembly constraints by using the
Automatically Convert Constraints to Joints tool( công cụ ).
With the Automatically Convert Constraints to Joints tool activated (kích hoạt ) you can continue creating fur-

ther Standard Joints by creating more Assembly Constraints within the Simulation environment.
The contact remains permanent throughout the simulation.
The list of equivalent assembly constraints is not exhaustive.
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CHAPTER 1
An Introduction to Inventor Simulation
CÁC KHỚP LĂN
Khớp mô phỏng động – There are NO equivalent ( tương đương) assembly constraints
RI Cylinder on Plane
This allows ( cho phép ) motion between a cylinder and plane; for example, gear and
a rack.
RI Cylinder on Cylinder
This allows motion between two primitive cylindrical components in
opposite directions; for example, Spur Gears.
RI Cylinder in Cylinder
This allows motion between a rotating cylinder inside another
nonrotating cylinder.
RI Cylinder Curve ( đường cong )
This allows motion between a rotating cylinder and a rotating CAM.
Belt
This creates motion of two cylinders with the same speed(cùng tốc độ). An option
allows rotation in the same direction or as a crossed(chéo qua) belt.
RI Cone on Plane
This allows motion between a conical face and a planar face.
RI Cone on Cone
This allows motion between two external(bên ngoài) conical faces; for example,
Bevel gears
RI Cone in Cone
This allows motion of a rotating conical component within a stationary(ở một chỗ)
conical component.

Screw (Vít)
This is the same as a cylindrical component but also allows you to
specify pitch(xác định cao độ).
Worm Gear
This allows motion between a worm gear component and a helical gear
component.
Rolling Joints can be automatically created for Spur Gears designed using Design
Accelerator.
The primitive(ban sơ ) surfaces are created by Design Accelerator and need to be made visible (rõ ràng) to be
able to select to create Rolling Joints.
There is no sliding between components and motion is 2D only.
The contact remains permanent throughout the simulation.
SLIDING JOINTS
CHAPTER 1
An Introduction to Inventor Simulation
Dynamic simulation joints – There are NO equivalent( tương đương ) assembly constraints
SI Cylinder on Plane
This allows sliding between a nonrotating cylinder and plane.
SI Cylinder on Cylinder
This allows sliding between two primitive cylindrical components in
which one cylinder is nonrotating.
SI Cylinder in Cylinder
This allows sliding between a nonrotating cylinder inside another
nonrotating cylinder.
SI Cylinder Curve
This allows motion between a nonrotating cylinder and a rotating CAM.
SI Point Curve
This creates motion of a point on one component to stay on a curve,
which can be defi ned by a face(s), edge(s), or sketch(es).
You can select sketches, faces, and edges to create joints.

The primitive surfaces are created by Design Accelerator and need to be made visible to be
able to select to create Rolling Joints.
There is no rotation between components and motion is 2D only.
The contact remains permanent throughout the simulation.
2D CONTACT JOINTS
Dynamic simulation joints – There are NO equivalent assembly constraints
2D Contact
This allows motion between the curve of component and curve of another
component.
You can select sketches, faces, and edges to create joints.
The motion is 2D only.
The contact can be nonpermanent throughout the simulation.
FORCE
Dynamic simulation joints – There are NO equivalent assembly constraints
Spring/Damper/Jack
This allows you to create springs, jacks, or dampers.
3D Contact
This allows you to create contacts between two components. It is based
on spring-damper( giảm chấn ) forces.
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CHAPTER 1
An Introduction to Inventor Simulation
The 3D contact settings are very sensitive ( nhạy cảm ) to change. Only change, if necessary( cần thiết ), when model is
not working.
The 3D contact only takes single components into consideration even though the subassembly is
selected. So create contacts between all components that have contacts with the subassembly.
Joints matrix – a snapshot of joints used throughout the book
Dynamic simulation joints Examples were
used
Design problems

were used
14
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
26
27
28

Revolution
Prismatic
Cylindrical
Spherical
Planar
Point-Line
Line-Plane
Point-Plane
Spatial
Welding
RI Cylinder on Plane
RI Cylinder on Cylinder
RI Cylinder in Cylinder
RI Cylinder Curve
Belt
RI Cone on Plane
RI Cone on Cone
RI Cone in Cone
Screw
Worm Gear
SI Cylinder on Plane
SI Cylinder on Cylinder
SI Cylinder in Cylinder
SI Cylinder Curve
SI Point Curve
2D Contact
Spring/Jack
3D Contact
All
2 & 3

4
1
2 & 3
4
2
2
1
9
All
4,5
1,3,4,5,6,7
3,4,6
3,6,7
Not used
1
2
Not used
7
Not used
2
Not used
Not used
Not used
Not used
7
5,7
1
3,6
Process of creating joints
CHAPTER 1

An Introduction to Inventor Simulation
The process of creating joints is probably the most time-consuming process especially
when you have a large assembly. This process can be drastically enhanced by being able
to group components that have no relative motion between them. There are two options to
do this.
Option 1 – Restructure components into subassemblies.
Option 2 – Weld components together.
Step 1
Once the grouping of components has been achieved, there are three options to create Stand-
ard and some Rolling joints.
Option 3 – Automatically Convert Constraints to Standard Joints.
Step 2
Option 4 – Manually Convert Constraints to Standard Joints.
Option 5 – Manually create Standard Joints.
Here , I will attempt to explain the above options of grouping components and creating
joints by using a series of examples.
■ Example 1 – Newtons-Cradle – Options 1 and 2
■ Example 2 – Whitworth Quick Return Mechanism – Option 3
■ Example 3 – Slider Mechanism – Option 4
■ Example 4 – CAM Follower Mechanism – Option 5
EXAMPLE 1
Newtons-Cradle – Grouping Components Workfl ow of example 1
• Automatically convert constraints to standard joints
• Restructure parts into subassemblies
• Weld parts together
• Lock joints degree of freedoms
Joints used in example 1
• Revolution
• Spherical
• 2D Contact

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CHAPTER 1
An Introduction to Inventor Simulation
Automatically convert constraints to standard joints
1. Open Newtons-Cradle1 .iam
Chúng ta sẽ thấy có 7 viên bi và 7 sợI dây. Có một điểm ràng buộc giữa quả bong và sợI dây, và một điểm ràng buộc giữa sợI
dây và sườn . Trong toàn bộ có 3 rang buộc và mỗI cặp bong kiên kết nhau.
2. Select Environments tab Dynamic Simulation
This will activate the Dynamic Simulation environment.
CHAPTER 1
An Introduction to Inventor Simulation
17
In the Dynamic Simulation browser, notice that a spherical( cầu) joint is created between the ball
and rope (Mate:1 – Point constraint), and a revolution joint is created between the rope and
frame (Mate:2 – Point constraint and Mate:3 – Axis Constraint). This is done seven times so
14 joints are created in total.
To see how simulation converts constraints to joints refer to page 11 Standard Joints and see
how constraints are converted to joints (this table is not exhaustive). Also note the number
of joints created is not related to the number of constraints.
Another point is that you can create rigid groups automatically by adding more constraints. For
example in this case by adding a mate constraint between a plane of the ball, and one of the
ropes, we will lock all degrees of freedoms between these 2 parts. Dynamic Simulation will then
create a rigid group containing the ball and the rope (as if you manually created a weldment).
For the Newtons-Cradle to work properly, the rope and ball will need to move together such
as there will be no relative motion between the ropes and balls. With this in mind, we can
restructure the ball and rope components into one subassembly; this will hopefully simplify
the joints process by reducing the number of joints created.
3. Close Newtons-Cradle1 .iam fi le
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CHAPTER 1
An Introduction to Inventor Simulation
Restructure parts into subassemblies
4. Now open Newtons-Cradle2 .iam fi le
You will now see 7 subassemblies, each containing( chứa) one ball and associated rope.
Additionally, there is now one point and axis constraint between the subassembly and frame.
In total, there are now 2 constraints for each subassembly.
5. Select Environments tab Dynamic Simulation
In the Dynamic Simulation browser notice there are now 7 joints instead of the original 14
joints.
CHAPTER 1
An Introduction to Inventor Simulation
Restructuring ( sắp xếp lại) your components into subassemblies, like this, will affect your bill of materials
database as now instead of having 7 balls and 7 ropes it will have 7 subassemblies. If you do
not want to affect your bill of materials or want to create another assembly for simulation
purposes, the only alternative(xoay chiều) is to weld components together within the simulation environment
before you create the joints, automatically or manually.
6. Close Newtons-Cradle2 .iam fi le
Weld parts together
7. Now open Newtons-Cradle3 .iam fi le
8. Select Environments tab Dynamic Simulation
All components are now grounded as no joints have been defi ned between them, and the
Automatically Convert Constraints to Standard Joints button is deactivated. This is important
because you cannot weld components together that have joints already defi ned between them.
9. Select NC-Ball:1 and NC-Rope1:1 Right Click and select Weld parts
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CHAPTER 1
An Introduction to Inventor Simulation
Now notice that both components are welded together as one. This is the same as restructuring components together as

subassemblies but without affecting the Bill of Materials database.
You cannot use Automatically Convert Constraints to Joints, as this will not take into account
that you have manually welded components together. So, now you will need to convert the
joints manually, either by converting constraints to joints or by using the Insert joint tool. We
will use the former method, and this is further used in Example 3 – Slider mechanism.
10. Select Convert Constraints
This will enable( kích hoạt) you to create joints from existing Assembly Constraints manually.
11. Select the 1st Rope and Frame as the two components that need their constraints
converted to joints
CHAPTER 1
An Introduction to Inventor Simulation
In the Convert Assembly Constraints dialog, the two constraints, between the new welded
component and the frame, are converted to a revolution joint, as expected.
You will need to repeat steps 9–11 six more times to complete the standard joints process for
all components.
We had to create two assembly constraints between each subassembly (or welded group) and
the frame, to achieve the desired revolution joint. We can achieve this same effect by only using
one point constraint between the subassembly and frame, thus eliminating the time needed to
create extra constraints. This is outlined below.
12. Close Newtons-Cradle3 .iam
Lock joints degree of freedoms
13. Open Newtons-Cradle4 .iam
You will see that there are still 7 balls and ropes subassemblies. But the difference now is that
there is only one point constraint between each subassembly and frame. In total, there are
now 7 constraints rather than 14 as in the previous example.
14. Select Environments tab Dynamic Simulation
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You will now see that 7 spherical(cầu) joints are automatically created, instead(thay thế) of a revolution
joint. This is because we only used the point constraint between the two components.
We will now alter these spherical joints to behave like revolution joints without need to cre-
ate more assembly constraints.
15. Select all Spherical Joints Right Click and select Properties
16. Select dof 2 (R) Tab in the Joints dialog box Lock the position as shown
We have just locked the rotation about this degree(bậc) of freedom (tự do).
We will further discuss joints properties later within the Environmental Constraints Section.
17. Select dof 1 (R) Tab Lock the position as shown
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An Introduction to Inventor Simulation
We have just locked another rotation of the spherical joint. This will now make the spherical
joint behave like a revolution joint.
18. Click OK
All joints now have a # symbol assigned to them, meaning the joints have locked degrees
of freedom.
Now , I hope you can appreciate (đánh giá ) that by simply restructuring the components into subassem-
blies and welding components together can have signifi cant impact on the number of joints
created. We will now discuss how to create joints in more detail.
19. Close Newtons-Cradle4 .iam
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EXAMPLE 2
Whitworth Quick Return Mechanism – Automatic Joints
Workfl ow of example 2 Joints used in example 2
• Automatically convert Standard Joints and • Revolution
Rolling Joints • Prismatic
• Create other Nonstandard Joints • Point-Line

• Rolling – Cylinder on Cylinder
Note : The only Rolling Joints that can be converted • Sliding – Cylinder on Plane
automatically are between Spur Gears that have been
created using Design Accelerator.
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Automatically convert standard joints and rolling joints
Here , we will create automatic joints from assembly constraints and attempt to analyze how
Dynamic Simulation creates joints.
1. Open Whitworth Quick Return .iam
In the Assembly browser, notice that four parts are grounded and the remaining( còn lại) four
components are constrained predominantly(mạnh hơn) using the insert constraint (equivalent joint
is revolution). You may need to expand the components to see the constraints.
2. Select Environments tab Dynamic Simulation
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In the Dynamic Simulation browser, notice that the components grounded in the assembly
environment remain grounded within Dynamic Simulation. The rest (cột, đứng yên) of the components
including Spur Gear subassembly become part of the mobile group; this is because the
assembly constraints between these components have been converted automatically to
Standard and Rolling Joints.
For Dynamic Simulation to convert Spur Gear (created by Design Accelerator) constraints to
Rolling Joints, do not alter (sử đổI) the hierarchy(trật tự ) of the subfolders (danh mục con ) created by Design Accelerator.
The reasons (ráp lại)why constraints are created automatically to joints is because automatically
convert constraints to standard joints is activated()kích hoạt ) within the dynamic simulation settings. We
will check this in the following steps.
3. Select Simulation Settings
Within the Dynamic Simulation Settings dialog box, we can see Automatically Convert

Constraints to Standard Joints is activated.
4. Click Cancel
Now , we will attempt ( gọI lạI )to analyze the joints converted from Assembly Constraints.
■ Revolution:3 Joint – Indicates (chỉ rõ )result as predicted (dự báo ).
■ Welded group:2 – Not as predicted – Expecting ( kỳ vọng ) a revolution joint – Instead ( thay thế )created a
welded joint between both components as if they were welded together in reality.
■ Pointed-line:4 Joint – Not as predicted – Expecting a revolution joint – Instead
created a point-line joint creating extra three degrees of freedom ( bặc tư do ) between the two
components.
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The only explanation for this is to avoid creating redundant( siêu tĩnh) joints (joints overcon-
strained) dynamic simulation has created the joints and welded bodies as illustrated ( minh họa ) below bên
dưới.
Redundant Joints are discussed in detail( bộ phận) later ( chậm hơn )in the chapter.
The only way to alter the converted joints is to modify the assembly constraints and this
process (chế tạo )can become tedious( chán), especially for a large assembly with redundant joints.
Another option is to manually convert constraints, but this option is disabled (mất tác dụng) when the
Automatic Conversion of Constraints is activated as shown below. This option gives you
more control on how joints are created and this process will be illustrated in Example 3.
For now, we will continue with Example 2 to create more nonstandard joints.
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