FBD Assignment: Analyzing Constraints, Forces and Idealizations

This assignment focuses on Free Body Diagrams (FBDs) within the context of mechanical engineering. The assignment requires students to analyze various scenarios involving constraints, degrees of freedom, and forces. Students must identify and document degrees of freedom for different objects, analyze specific connections with constrained motions, and draw FBDs. The assignment also explores different idealizations and working conditions, displacement-based constraints, and the simplification of constraint forces. Students are expected to apply Newton's third law and make relevant assumptions. The solution includes photographs, coordinate systems, and concise descriptions of the functionality of constrained degrees of freedom, and the provided template guides the presentation of the findings. This assignment aims to enhance the understanding of force analysis and the behavior of mechanical systems.

ASSIGNMENT 1
lnvoles some photography and marking it. Put the pictures in a word document and the answers below
it .
+ Helpful videos:
_ Fbd 3d constraints:
https://www.youtube.com/watch?
v=bph5tPpzbYQ&list=PLUj5PZVZkwnLGMyBuY2R0J2eksyvLqP19&index=7
_ Fbd worked examples:
https://www.youtube.com/watch?
v=o32TZ4ed_B0&list=PLUj5PZVZkwnLGMyBuY2R0J2eksyvLqP19&index=8
Project Objectives
By doing the FBD assignment, students should be able to:
1. Acknowledge 6 possible degrees of relative motions at a joint. This
includes three translations and three rotations which are
independent.
2. Recognize that the degrees that are actually constrained in a joint can
be selected in many ways. Based on the functionality of a given joint
in a real life structure/mechanism, identify the actual degrees that are
constrained.
3. Acknowledge constraining a particular degree results in a
corresponding constraint force.
4. Account for the constraint forces in FBDs.
5. Apply Newton's third law when isolating a joint.
6. Idealize effects of friction, motors, spring, etc., based on
functionality.
Use the template provided at the end.
6DOFs
A: Find an object, show its picture and mark the six degrees of freedom for it.
Specific Connection
B: Find a connection with exactly 2 rotations and 2 translations constrained (so only 1 translation and
one rotation is allowed)
1. Show its photo and a coordinate system.
2. Identify the constrained DOFs.
3. Draw its FBD.

4. In no more than 2 lines, describe the functionality of all the
constrained DOFs.
5. Highlight relevant assumptions.
Two Different Idealizations
C: Find a system with two different idealizations or two different working conditions.
1. Show its photo and a coordinate system.
2. Identify the constrained DOFs.
3. Draw FBDs for the two idealizations.
4. In no more than 2 lines, describe the functionality of all the
constrained DOFs.
5. Highlight relevant assumptions.
Conditional Constraints
D: Find a system with displacement-based constraints (i.e some kind of motion limits) .
1. Show its photo and a coordinate system.
2. Identify the constrained DOFs.
3. Draw FBD.
4. In no more than 2 lines, describe the functionality of all the
constrained DOFs.
5. Highlight relevant assumptions.
Force Simplification
E: Identify a system with complicated/distributed constraint forces.
1. Show its photo and a coordinate system.
2. Identify the constrained DOFs.
3. Draw two FBDs: one for the distributed constraint forces and
one for a simplified version appropriate for rigid body
equilibrium analysis.
4. In no more than 2 lines, describe the functionality of all the
constrained DOFs.
5. Highlight relevant assumptions.

Template for what to present
1. Show its photo: Connection marked by the red box.
2. Identify the constrained DOFs.
Relative translation in x: Yes
Relative translation in y: Yes
Relative translation in z: Yes
Relative rotations in x: Yes
Relative rotations in y: No
Relative rotations in z: No
3. Draw its FBD.
4. In no more than 2 lines, describe the functionality of all the constrained DOFs.
The pin joint serves as a cap.
5. Highlight relevant assumptions.
- No friction.
- Applied forces are well under working conditions.