Truss Project

Question 1

Tension sticks

Answer 1

Tension capacity of a stick is determined by end distance

Generally tension capacity increases with end distance

Question 2

Compression Member

Answer 2

Critical buckling load is equal to
Pi squared x elastic modulus (material stiffness) x second moment of area (section shape)
Divided by effective length squared (in mm)

Question 3

Effective length

Answer 3

The length that is in the buckling shape
With both ends pinned effective length is L
With one end pinned, one end fixed, l is 0.7L
With both ends pinned l is 0.5L

Question 4

Wood compression information

Answer 4

For wood, X = 740000

Compression increases by 8, then 27

Question 5

Drill press

Answer 5

Chuck is the drill part
Feed lever is what is used to lower chuck
Tilt table is the surface that objects are out on
Safety:
Wear glasses
Tie back hair
Keep fingers 30mm away from chuck

Question 6

Safety analysis

Answer 6

Determine the likelihood and severity of the event and it gets a rating of low, moderate, high or critical
Order events to these ratings and then put the worst outcome and how to minimise

Question 7

NZ health and safety

Answer 7

The designers must, so far as it is reasonably possible, ensure the plant, substance or structure is designed to be without risks to the health and safety of persons who use, handle, store, construct, carry out reasonably foreseeable activity and others in the vicinity of and might be exposed to the plant, substance, structure

Question 8

How our Truss Failed

Answer 8

Global Buckling

Question 9

How we could fix our truss

Answer 9

More secure cross members
Build member EG differently, so that it has 2 sticks glued together instead of 3 with gaps at the end, as the gaps made it weaker
Make truss so it can be modelled, no member angled in z direction