Minutes of Group Meeting 6/12/11

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

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.

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.