saurabhjain

Why designs fail? Invitation for open discussion

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With so much scientific tools, why do designs fail?

Please add your comments by replying below and invite all your friends for participation.
 

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When deriving a formula we took some assumptions. But some cases those assumptions not happening so the design is fail

ameyb94 likes this

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One cause I think we will begin to see more of is due to the confusion of what design is. At one time not too long ago an engineer would do a design. The design started with some form of a requirements document or product description. The design consisted of: sketches, engineering calculations for predicted loads and load paths, stress analysis, sizing of members, bearing, seals etc. This information was given to a designer or drafter who would create the art. With young engineers having ready access to 3D CAD and simulation the creation of the Art is mistaken as the design. Simulation can do some of the upfront work during the creation of the Art but I have found too many who don't know how to use the simulation because the basics are not being learned due to the rush to create Art, and thinking that is design. A recent project I was reviewing was canceled when I sent in my preliminary findings. The intern created an impressive CAD model. When I broke out the advanced tools, pencil & paper, then created the free body diagrams, the Art was just that. At the beginning of the project I asked for the calculations. None could be found. 

My recent Blog I Thought You Knew That, may also shine some light on the causes.

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Design comes to a failure because it works in a simulation of perfection, with no environment or external forces such as pressure, wear of the system itself etc. Design has to have a scaled model to discard these troubles first, a lack of a prototype made of "try and mistake" will lead to a failure or have many bumps in the way to success. Have just happend to me in a complex Biorreactor model made in cad, when it came into the build and test, it failed horribly due to the design couldn't never tell the insides and external environment issues that affects the operation of the system even all mechanical was taken in consideration. Won't happen again.

Greetings.

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I agree with JAG Engineering LLC; a design is not only the “art” work done in CAD softwares.  A complete design has to go through some sort of validation process like meeting the already defined requirements, build processes, regulations, etc.  Now, if an “art” work is done as the 1st step in the design process and then found as it would not meet the initial requirements during the validation process it should not be considered as a design failure because it never passed the concept stage.  New technologies have started from cartoons drawn in a napkins and then modified to meet the consumer requirements.

 

The way I see it, designs can fail for many reasons.  In the industry I work cost, weight and time are the main influences for an end design.  Therefore, juggling all these factors while mitigating risks can affect heavily the success of the final design.

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I think every engineering firm is behind completing projects on given deadline. But as Engineer every Drawing, Calculations need to be Sanity checked at least three times. This is time spending activity which costs money. 

Other reason, Sometimes engineers are made limited to work only in office rather than exploring the site or company whose products they design. 

Knowing the how things are manufactured is most important as each feature cost money to make. There might some compromises made which could lead to failure as well. Visit manufacturer should be regular thing to see and ask how its made.

 

saurabhjain likes this

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It is helpful to have specifications for the job that the design will accomplish to start with, it is then good to run FEA to validate the design. FEA can be a valuable tool if the proper and accurate data is entered into the program. I add a Factor of safety of at least 20% for my comfort but I frequently overbuild when I design production machines used in house where there is no issue with weight. A wise engineer once told me "You will be criticized for a design that fails long before being criticized for one that was too strong." When designing a product that has to be lightweight, I still overbuild at first and then find ways to lighten it as I refine the design.  Personally I like to see multiple prototypes physically tested to extreme failure and the data collected, analysed and compared to customer requirements, I do not feel comfortable passing off a design that has not undergone a battery of testing.

One of the reasons that I have seen designs fail is lack of experience.....education should include practical experience and application. Just because one has a degree from a university doesn't mean one is a competent engineer, I have worked with many green engineers who couldn't design their way out of a wet paper bag and were too proud to admit that they might not know something. In my opinion, engineers who ask more questions before designing a product, build better products in the end. Don't let your ego get the best of you! Also I believe it is extremely helpful to know as much as you can about the process or system that you are designing for, play production worker for a week if you can, you will gain valuable insight and gain allies on the production floor, both can be invaluable! 

Participating in design reviews can be a valuable resource. Remove yourself from your ego and listen to what your colleagues have to say and don't be so invested in your own ideas that you do not hear the other ideas in the room. Many heads have many ideas and combining ideas is a great way to make great designs.

Lastly, dare greatly! Failure is part of life! Learning what doesn't work is how you work toward discovering what does! Do not let fear of failure inhibit your education, make your best design and try it, when it fails refine it, if it fails again, refine it again and try not to repeat the same mistakes. If you study the history of any great invention you will usually find a string of failed experiments that lead to a great discovery and a person who learned from their failures. Your failure will only define you if you let it.

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In most of the products made as per design need some modifications after the product has been practically tried and this can not be termed as failed design

Also,a perfectly designed machine may fail during use due to number of other related factor such as operational parameters like pressure,temperature,environment,load,speed.Also,it must be ensured that the personnel operating the machine have got necessary technical skills.

In short,before declaring a failed design,thorough analysis must be carried out to pin point the cause of failure.

Raymond Scott Adams likes this

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On 4/19/2017 at 7:01 AM, Raymond Scott Adams said:

It is helpful to have specifications for the job that the design will accomplish to start with, it is then good to run FEA to validate the design. FEA can be a valuable tool if the proper and accurate data is entered into the program. I add a Factor of safety of at least 20% for my comfort but I frequently overbuild when I design production machines used in house where there is no issue with weight. A wise engineer once told me "You will be criticized for a design that fails long before being criticized for one that was too strong." When designing a product that has to be lightweight, I still overbuild at first and then find ways to lighten it as I refine the design.  Personally I like to see multiple prototypes physically tested to extreme failure and the data collected, analysed and compared to customer requirements, I do not feel comfortable passing off a design that has not undergone a battery of testing.

One of the reasons that I have seen designs fail is lack of experience.....education should include practical experience and application. Just because one has a degree from a university doesn't mean one is a competent engineer, I have worked with many green engineers who couldn't design their way out of a wet paper bag and were too proud to admit that they might not know something. In my opinion, engineers who ask more questions before designing a product, build better products in the end. Don't let your ego get the best of you! Also I believe it is extremely helpful to know as much as you can about the process or system that you are designing for, play production worker for a week if you can, you will gain valuable insight and gain allies on the production floor, both can be invaluable! 

Participating in design reviews can be a valuable resource. Remove yourself from your ego and listen to what your colleagues have to say and don't be so invested in your own ideas that you do not hear the other ideas in the room. Many heads have many ideas and combining ideas is a great way to make great designs.

Lastly, dare greatly! Failure is part of life! Learning what doesn't work is how you work toward discovering what does! Do not let fear of failure inhibit your education, make your best design and try it, when it fails refine it, if it fails again, refine it again and try not to repeat the same mistakes. If you study the history of any great invention you will usually find a string of failed experiments that lead to a great discovery and a person who learned from their failures. Your failure will only define you if you let it.

 

i have to say in any branch of knowledge practice is very important that only sharpens - see as lawyers we use incisive questions besides again revisit with further interagations why, then only  you can do real research on the problems - in law we ask too many questions even our own clients, to get at the heart of the issue, that is what we call sensible designing to progress further to ensure whether our client can really convince his stand with the judges....that is also called dynamic designing,

Raymond Scott Adams likes this

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In the interest of being more accurate, I would ask more questions in regard to the question: Is there a specific application where designs are failing that you are referring to?  As I have been thinking on this subject it occurred to me that some products are designed to fail as a means to create repeat business I.E. the auto industry is replete with examples of this where parts and material are selected to meet a predetermined somewhat predictable life cycle with cost constraints in place, #1 because wear is inevitable #2 materials that wear longer are generally more expensive and may price a product out of the market. Needless to say If your product never fails or wears out, you may eventually saturate your market, or your product may be too expensive to reach a broader customer base.  In this respect product design is a balancing act between longevity, vs. price constraints vs. customer expectations vs. marketability etc. All of these things come into play as well as the fact that there is no way to control all of the outside factors that a product will be influenced by such as lack of maintenance, misuse and or abuse, adverse conditions etc. This brings to mind the questions: Is the product performing to the design intent? Is the product performing it's task for a reasonable life cycle? If the product fails due to lack of maintenance are you considering that a design failure? In my opinion if you can answer yes to the first two questions then you have met your design objective.  Once a product is put on the market and into use you will inevitably discover that there are situations that arise that were not anticipated by the original design and a refinement must be implemented to meet the criteria of a new set of parameters, this is just a reality of engineering. The key is to develop short feedback cycles into your processes so that you can discover and solve problems quickly.  I find it very effective to ask for customer feedback quickly and to respond to it quickly in order to develop an enduring relationship, and all customers are important whether it be your co-workers or end users, a satisfied customer is the ultimate test of any design! 

saurabhjain likes this

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Quite a few interesting comments on reasons for design failure. Thank you JAG in particular.

I would like to tell a story about a failure that I saw once long ago that was somewhat different. It involved a design that had been developed in a government laboratory, manufactured in very small quantities with tight controls for testing, and then put out to industry for mass production. In order to bring the unit price down, the government arbitrarily specified rather loose tolerances, far more loose than anything that had been allowed in the development phase. But then, the government added a performance specification, that the product must function according to design.

The result was that the mass production companies were bidding, based on nothing more than the drawings and specifications. It was implicit in the drawing package that a product made according to the drawings was expected to meet the performance specifications, and this was the way the bids were developed. My company was unfortunate enough to win the bid. We found through bitter experience that it was entirely possible to build the product according to the drawings but still fail the performance test at the end. This resulted in massive amounts of rejected products. My job was to show mathematically that this was entirely possible, that the loosened tolerances allowed for performance failure.

This was a failure driven by a desire to reduce costs to the purchaser. The result was the destruction of my employer; a company with over 100 years experience in the field was driven to bankruptcy.

DrD

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Dr. D’s story reminded me of two related stories, then another and then another...but I will stop with two.

The follow appeared in the Wall Street Journal 15-20 years ago. The happy ending was that the supplier finally won the court case against the US government. The unhappy part of the story, was that it cost the company much time and money. The article went on to say that a lot of companies go bankrupt from similar situations, but I digress.

The government contracted with a commercial supplier to produce a device. The full-up device had a performance specification. The government was to provide the power supply that would be part of the final product. The government was never able to provide a power supply that met the government's own specifications, yet the government expected the supplier to provide an end item that was to specification, using an out of specification power supply.  Only a government could keep a straight face and insist this made any sense.

The other example can be found at the link below, titled What do you mean you made it as we told you to?

https://www.linkedin.com/pulse/what-do-you-mean-made-we-told-joseph-a-gulino-pe?published=t

At the above LinkedIn site you will find other articles by me.

saurabhjain likes this

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JAG:  Only a government could keep a straight face and insist this made any sense.

Amen, amen, amen!!

DrD

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