The group met today to present and discuss the work which we
had done over the past week, select a concept and to allocate tasks for the
coming week. Attending were:
·
Dave Brown
·
Ross Catchpole
·
Rich Brennan
·
James Golding
·
James Flanagan
The group agreed on a
system by which to score the concepts which were drawn out, considering each
category and weighting it as to how important the factor was in our design.
Each idea was then given a score between -3 and 3 for each category, and the concept
with the highest score will be developed to become our final design. To
clarify, portability was defined as how easily the crane could be broken down
and moved, and mobility was based on the range of positions the load could be
deposited in. It was also agreed that the weak link and carrying handle
concepts will be incorporated into the design.
|
|
Weighting
(multiplication factor)
|
Gantry Crane
|
Tripod with Adjustable Legs
|
Tripod with Rubble weighted Base
|
Spider Crane
|
|
Portability
|
4
|
2
|
0
|
-1
|
1
|
|
Mobility
|
3
|
0
|
1
|
-1
|
1
|
|
Cost
|
4
|
2
|
1
|
0
|
-1
|
|
Ease of Manufacture
|
3
|
2
|
0
|
1
|
-1
|
|
Ease of Use
|
2
|
1
|
0
|
-1
|
1
|
|
Total Score
|
|
24
|
7
|
-6
|
2
|
|
Position
|
|
1
|
2
|
4
|
3
|
The Gantry Crane concept was the clear winner; however it was
felt that it was not perfect and
improvements could be made. These mostly
related to stability and adjustability and were agreed on. They have been
incorporated into the design sketch which will also be uploaded to this blog.
James Flanagan presented the research which he had done into
materials (which will also be uploaded) and it was decided overall that aluminium
was the best choice to make the crane out of due to its corrosion resistance,
ease of working and good strength to weight ratio relative to its price.
Titanium and composites were both superior in their strength to weight ratio
however their price, both as raw materials and the increased cost of
manufacture related to working with them, made them a less than ideal choice
for the design.
Ross Catchpole is to look into joint designs suitable for the
chosen concept this week and discuss them with Dave Brown to draw into the
design in time for the group meeting next week, due to the huge number of possibilities
available when all concepts were considered in research this week.
Tasks to be done and presented and the next group meeting:
Ross Catchpole – Research harnesses and Load connections
suitable for the crane
Dave Brown – Sketch Final Design (with joints in)
Start CAD of design
Start CAD of design
Rich Brennan – Start stress analysis of design and determine
required second moment of area.
James Flanagan – Assist with stress analysis and CAD.
Find strength values for different types of aluminium and their limitations.
Research coatings.
Find strength values for different types of aluminium and their limitations.
Research coatings.
James Golding – Research winch and pulley systems suitable
for crane. Include electric winches and their power sources.
The next whole group meeting will be on 12/12/11.
