Motovated > News > Newsletter August 2009

Hello everyone,

We are hopefully over the worst of the winter weather, with only one week left until spring! Let's hope we see some spring weather and some spring in the economy in the next few months. We have a number of interesting articles in this issue, including a summary of Finite Element Analysis (FEA) techniques, balancing out left and right brain functions for success in business and design, and our locomotive feature as promised.

We also have a design tip with some stress results for downloading, another brain teaser and answers to last issue's question.

Greg Morehouse
General Manager
Engineering Analyst

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Finite Element Analysis - a summary

There are many different Finite Element Analysis (FEA) packages available now, and there are also different analysis techniques available to the analyst. The analysis technique can be chosen to suit the accuracy, cost and software capability, and are summarised below:

TREND ANALYSES	COMPARATIVE ANALYSES	ACCURATE ANALYSES
Can be done in limited FEA software such as COSMOSXpress, SimulationXpress, FEMAP Express or others. Require little time and money upfront Don't require good loads or accurate boundary conditions Very helpful in highlighting in-expensive improvements Insufficient for final validation prior to physical testing	Useful for products already proven to work Allow use of limited boundary conditions, material properties and loads Provide indicative but not accurate results Highlights if the design changes are better or worse than the original design Can be adequate for validation prior to physical testing	Especially useful for new or unknown products Require good knowledge of the product, loads, boundary conditions and materials Often requires high-end FEA capability and computing resource, and significant investment Delivers 'actual' stresses and deflections etc. Note however that any FEA analysis is still an approximation to some extent
Read the full article on our website

Balancing Act - left and right-brain functions

We also have some interesting articles from designindustry on the characteristics of left and right-brain dominated organisations, and the strengths and weaknesses of each. You can read each article by clicking on the links opposite.

Motovated works with a lot of different organisations and clients, and can help bring the balance needed to any kind of project or design. We help creative people with innovative ideas by adding analysis, logic and reality checks. We also have a great design team to generate ideas and clever solutions.

It is the synergy between creative design and logical analysis that Motovated is founded on. You can also read some of our clients testimonials on our website

Thanks to Dorenda Britten and Fraser Scott, designindustry Limited www.designindustry.co.nz for the use of the articles

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Tips & Tricks - machine bracket redesign

Original Casting	First Redesign	Second Redesign
Images sourced from Design of Weldments, Omer W. Blodgett

In this issue, we take a look at redesigning machine brackets to reduce the manufacturing cost. This can be done a number of ways, including changing the material, method of manufacture, and changing the load path.

Most machine brackets are either cast iron or welded steel. A quick comparison of material properties shows that for equal strength, steel sections can be 25% of the size of cast iron sections. For equal stiffness, steel sections can generally be 50% of the thickness of cast iron sections.

As weld metal is expensive, welded bracket designs push ahead of cast designs only when the amount of welding can be kept to a minimum, and high-speed downhand fillet welds are utilised. In many cases, components can be profiled or sheared from relatively thin sheet and bent to shape to reduce parts and weight. Thickness can easily be added where needed. Casting limitations on thicknesses and draft angles can often result in heavier components than their welded counterparts.

As with any design, it is not a one-rule-fits-all situation. Depending on the production numbers involved, aesthetics, amount of welding, weight, part complexity and the dimensional accuracy required, both cast and welded brackets have their place.

The example opposite shows the improvements made in redesigning a simple cast bracket as a welded bracket. To ensure that the modified bracket performs to the same level or better than the original, a comparative analysis was run. Follow the link opposite to see the results.

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Locomotives in New Zealand - Part 1

Diesel-electric locomotives were first introduced in the 1950's, and have now become the standard locomotive work-horse in New Zealand. The majority of traffic is freight, with 4 long-distance passenger routes still in operation.

In this article we discuss the procurement options available, and the current procurement of locomotives from China.

Options for Procurement
New Locomotives from China

Thanks to Glenn Sutherland and Mike Jacobs for their contributions to the above articles.

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Outsmart your colleagues...

This issue's brain teaser is: Can you arrange 24 coins in six rows with five coins in each row?

Send your correct answer to competition@motovated.co.nz to be in with a chance of winning a $50 Mitre 10 voucher.

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Answer to last issue's puzzle

Check your answer to June issue's question here:

Candlesticks	Shavings
27	9
9	3
3	1
1	1/3
27 + 9 + 3 + 1 = 40

Does Norm have enough material to fill the order? There were a number of different solutions sent in, the most common approach is shown opposite.

After turning 27 candlesticks, Norm melts down the shavings to make nine rods, from which he can turn nine more candlesticks. The shavings from these nine will yield three more rods, making three more candlesticks. Then, with the shavings from these last three, Norm can make one final rod to use for the last candlestick. Total: 40 candlesticks, with a few brass shavings left over.

So the correct answer is yes, he can fill the order (with careful collection of all the shavings and 3 melting's required).

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Last issue's puzzle winner...

Congratulations to Tony Lissington of Compac Sorting Equipment, a Mitre 10 voucher is on its way to you.

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Thanks for your time and support. We look forward to working with you and continuing to provide the best engineering services possible.

Greg and the team at Motovated.

"engineering your vision"