Logbook constructing workshop

•  Compared with working with models you get a be6er idea of how structures work with actual materials. This is due to you being able to cut specific sizes and if your cu=ng isn't great or you get a very kno6y piece of @mber then you can see how they would actually act, as opposed to using uniform pieces. It is also handy to understand how to cut wood properly, in fact I was rather surprised that I was among one of the few that had ever sawed wood before.

•  Our teacher taught us the best way to saw wood is to ensure your index finger is pointed.

•  Photos 1,2 and 3 show our structure prior to being destroyed.

Photo 1, Jason Lee, (2014)



Zoe Brain 639 607

TOOLS… •  Pre6y much any equipment we could find in the

room except for wood items this was specific per group-‐ our group was permi6ed one piece of plywood and two pieces of pine for example. The structures were also required to span 1000mm and there were limits on how high it could be.

•  Other tools included: nails whatever size we found; hammers; handheld saws; pencil (for marking), vice (a6ached to the bench) and of course we all eventually tested our designs with a crushing type piece of machinery. We were also required to wear safety equipment by means of steel capped boots.

CALCULATE THE MOMENT: •  Moment (kNM) = force (kN-‐ kilo neutrons) x distance

(M) perpendicular (opposite) from the centre of rota@on.

•  M=Fd=NM •  Pressure= •  Force/Area= •  N/M^2

Zoe Brain 639 607




Photo 5, Jason Lee, (2014) Photo 6, Jason Lee, (2014)


Photos *,* and * show the process of maximum force being applied to our structure. The newt 3 photos, ( *,* and *) show the acermath and you can see that our structure has cracked up the centre and come apart towards the end by means of rota@ng. The maximum load that our structure took was approximately 210kg and the deflec@on between the 1st and 2nd tes@ngs was 40mm. ( If we had known exactly what would be tes@ng our designs we might have designed it differently).

Zoe Brain 639 607

•  Other teams produced very different structures as they were higher up thus they generally dealt with the load be6er as it could spread along the wood as opposed to being applied in one place, therefore their failure load was higher. For example the structure shown in sketch 1 had a failure load of 300kg as opposed to the 210kg ours took.

•  I personally didn’t like the design from the start and I was concerned about the weakening of @mber by means of cu=ng it, however the others in my group didn’t seem to care so we went with their idea.

•  Another thing to consider is knots in the wood (as shown below in sketch 2) which can cause cracking, which was the case in one of the groups structures and had there been no defect their failure load could have poten@ally been between 400 and 500kg as opposed to 300kg.

Sketch 2, by Zoe Brain, (2014)

Sketch 1, by Zoe Brain, (2014)

Zoe Brain 639 607

Logbook constructing workshop

Documents

Transcript of Logbook constructing workshop