Structural Elements

3 types:

• Bars (1D) - Only covered in s1
• Plates and Shells (2D)
• Blocks (3D)

Pin Joint

Doesn’t exert a moment. Free rotations are allowed. When only pin joints are used, bars will have only axial forces.

Bars

Here

• $N$ - Axial force
• $S_x,S_y$ - Shear force
• $M_x$

Types of bars

Axially loaded

Load causes tension or compression predominantly.

• Predomniant tension - Ties
• Predomniant compression - Struts

Flexural

Load causes bending predominantly. Example: beams.

Torsional

Load causes torque predominantly. Example: Shafts.