1. ENGR 34 Chapter 6, Day 3 3D Trusses & Frames
ENGR 34 Statics Chapter 6, Day D Trusses & Frames
ENGR Chapter 6, Day 3 3D Trusses & Frames
3D trusses
Constraints & rigidity
More 3D RB equilibrium practice

2. ENGR 34 Statics Chapter 6, Day 3 3D Trusses & Frames
3D Truss Analysis
All connections assumed ball and socket
All forces at joints
Each joint is 3D point FBD
2 J = M + R ?????
Tetrahedrons are strongest

3. ENGR 34 Statics Chapter 6, Day 3 3D Trusses & Frames
3D Truss Analysis
All connections assumed ball and socket
All forces at joints
Each joint is 3D point FBD
3 J = M + R
Tetrahedrons are strongest

4. ENGR 34 Statics Chapter 6, Day 3 3D Trusses & Frames
Non Rigid Trusses
Extra reactions may help

5. ENGR 34 Statics Chapter 6, Day 3 3D Trusses & Frames
Not all parts are 2 force bodies
Draw FBD’s for 3+ force bodies
Use Newton’s 3rd Law

6. ENGR 34 Statics Chapter 6, Day 3 3D Trusses & Frames
3D Truss Key Concepts
3 J = M +R
Joint method preferred
Assume Tension
Frames Key Concepts
Use 2 force body info
3+ force body FBD’s
Newton’s 3rd Law