Structures

Lesson 1A: Columns:

Using up to 5 sheets of paper, make a structure that will support a load( clay bricks) 8-1/2" off the table.

Using 5 sheets of paper and 12" of tape, create a structure than can support a minimum of 2 bricks 8- 1/2" above the ground.

Discussion of failure modes:

• Buckling

• Tipping over

• Crushing

Failure Modes:

(1) Imbalance-tips over (rotational motion)

(2) Long(slender) columns-

• • Buckling- fails at one point, then collapses

  • Euler Buckling: Critical load depends on length, stiffness, and cross-section of column.
    
    Thus for a given amount of material, a hollow column is less subject to buckling, as it has a greater cross-sectional area.

Typically fails at end- what happens if ends are reinforced, as in paper cups?

(3) Material Failure( Crushing)- Short Columns

Very short columns crush

Most columns are intermediate- fail partly in crushing and partly in buckling.