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Figure 1.9. General

approach to design.

After [1.191]

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DISEO CONCEPTUAL

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Example,:

Consider the improvement of a labyrinth seal in a high-speed turbine in

accordance with a set of requirements.

The task is described in detail by means of a requirements list and theformulation of the goal to be achieved.

Abstraccin y extensin sistemtica del problema.

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In the abstracting approach, the crux of the task would not so much be the

design of a labyrinth seal as that of a

shaft seal without physical contact,


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Attention must be paid to:

certain operating and spatial constraints,

cost limits and

delivery times.


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Specifically, the designer should ask whether the crux is:

to improve the technical functions, e.g. the sealing quality or safety

to reduce weight or space

to significantly lower costs

to significantly shorten delivery times

to improve production methods.


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All of these questions might have to be satisfied by the overall solution, but

their importance may differ from case to case.

Nevertheless, due regard must be paid to each of them, since any one of

them is likely to provide the impetus for the discovery of a new and better

solution principle.

New developments involving a proven solution principle, coupled to

modifications in production methods, are often imposed by the need to lower

costs and shorten delivery times.

Thus, if an improvement in the sealing properties were the crucial

requirement in the example we have mentioned, new sealing systems would

have to be found.


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Figure 6.2. The present

method of filling, storingand loading bags of feed.

After [6.5]


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Using abstraction and the systematic extension of what is already

known about the task.

The following problem formulations are possible, each representing a

higher level of abstraction than the last:


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1. Filling, weighting, closing and stacking bags of feed.

2. Transferring feed from the mixing silo to stacked bags in the warehouse.

3. Transferring feed from the mixing silo to bags on the delivery truck.

4. Transferring feed from the mixing silo to the delivery truck.

5. Transferring feed from the mixing silo to a delivery system.

6. Transferring feed from the mixing silo to the consumers storage bins.

7. Transferring feed from ingredient containers to consumers storage bins.

8. Transferring feed ingredients from their source to the consumer.


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Figure 6.3. Alternative formulations of the feed distribution problem, illustrating progressivelybroader formulations of a problem. After [6.5]. A = initial state; B = final state


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It may prove expedient not only to set up task-specific functions,

but also to elaborate the function structure from

generally val id sub funct ions

The latter recur in technical systems, and may be helpful when searching for a

solution.

They may lead to the discovery of task-specific subfunctions or because design

catalogues may list solutions for them.

Defining generally valid functions can also be of use when varying function

structures, for example to optimize the energy, material and signal flows.

The following list and examples should be helpful in this regard.

Funciones generalmente validas

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Conversion of mater ial:

Changing matter (e.g. liquefying a gas)

Varying material dimensions (e.g. rolling sheet metal)

Connecting matter with energy (e.g. moving parts)

Connecting matter with signal (e.g. cutting off steam)

Connecting different types of materials (e.g. mixing or separating materials)

Channelling material (e.g. mining coal)

Storing material (e.g. keeping grain in a silo)


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Convers ion of s ign als:

Changing signals (e.g. changing amechanical into an electrical signal, or acontinuous into an intermittent signal)

Varying signal magnitudes (e.g. increasing a signals amplitude)

Connecting signals with energy (e.g. amplifying measurements)

Connecting signals with matter (e.g. marking materials)

Connecting signals with signals (e.g. comparing target values with actual

values)

Channelling signals (e.g. transferring data)

Storing signals (e.g. in databases)


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Figure 6.9. a Function structure of a potato harvesting mach2.7ine b For comparison:

diagram with generally valid functions based on [6.1], Figure


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There are, however, some problems in which variation of the main flow alone cannot lead

to a solution,

because auxiliary flows have a crucial bearing on the design and are solution-determining.

As an example, let us consider the function structure of a potato harvesting machine.

Figure 6.9a shows the overall function and the function structure based on the flow of

material (the main flow) and the auxiliary flows of energy and signals.

In Figure 6.9b, by comparison, the function structure is represented by means of generally

valid functions, in order to emphasise the clear interrelationship of the different flows.


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Solution Finding Methods

The main advantage of the systematic approach is that designers do not have to rely on

coming up with a good idea at the right moment. Solutions can be systematically

elaborated using the relevant methods.

An optimal solution:

fulfils all demands in the requirements list as well as most of the wishes

can be realised by the company within the constraints of budget (target costing), time-

to-market, production facilities, etc.

Several steps are required to realise such a solution.

First, a range of possible solutions for the given task has to be generated. The basis for

this is the function structure (see Section 2.1.3) that is used to divide the overall task into

manageable subtasks.

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The function structure also provides the functional interrelationship between the

subtasks, by describing the relationship between the inputs and outputs of each

subfunction with respect to the flows of material, energy and signals.

In a second step, one or more possible physical effects are assigned to each of these

solution-neutral subfunctions in order to realise them.

This is done in accordance with the task-specific requirements. To realize a certain force,

for example, a physical effect with the appropriate capability needs to be selected. The

approach described thus far typifies the traditional approach of an engineer. A solutionspace is created because variants are generated while developing the function structure

and when selecting physical effects.

The use of a combination of solution-finding methods can be used to extend the solution

space.


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Often a subfunction can only be realized througha combination of several physicaleffects. This is another reason to use several solution finding methods.

Those that are proposed or described in the following sections originate from, amongothers, the area of creativity techniques with its generally recurring methods that are

described in Section 2.2.5. Others are based on analogical or logical reasoning.

Conventional Methods

1. Info rmation Gathering

For designers, access to state-of-the-art information is essential. The internet enables a

more effective and efficient application of the following conventional techniques:

searching the literature

analysing trade publications

surveying the presentations from exhibitions and fairs

assessing catalogues of competitors exploring patents, etc.


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2. Analysis of Natural Systems

The study of natural forms, structures, organisms and processes can lead tovery useful and novel technical solutions. The connections between biology

and technology are investigated by bionics and biomechanics.

Nature can stimulate the creative imagination of designers in a host of different

ways.

The hooks of a burr provided a solution that was incorporated into the Velcro

fastener (see Figure 3.10).


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Figure 3.10. a Hooks of a burr. b Velcro fastener. After [3.29]


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VelcroLas dos cintas del cierre de velcro: cinta con ganchosy cinta con fibras enmaraadas en bucle.

FuncionamientoEl sistema de cierre y apertura es rpido y sencillo. Consiste en dos cintas de tela que deben fijarse

en las superficies a unir mediante cosido o pegado. Una de las cintas posee unas pequeas pas

flexibles que acaban en forma de gancho y que por simple presin se enganchan a la otra cintacubierta de fibras enmaraadas que forman bucles y que permiten el agarre. [1][2]

HistoriaDetalle de los ganchos en las espinasdel frutode la bardana(Arctium lappa)

Se cuenta que en 1941, tras venir de un paseo por el campo con su perro,(laray anto) el ingeniero

suizoGeorge de Mestraldescubri lo complicado que resultaba desenganchar de sus pantalones y

del pelo de su perro los frutos de algunos cardos Arctiumconocidos como umpalumpas.. bardana

(Arctium lappayArctium minus) -otra planta con ganchos similares esXanthium spinosum-, ambaspopularmente conocidas, entre otros nombres, como arrancamoos. Tras comprobar la existencia de

un gancho en el final de sus pas o espinas se puso manos a la obra e invent un sistema de cierre

con dos cintas: el velcro.[1]

Origen del trminoLa palabra velcroproviene del francsvelours(terciopelo) y crochet(gancho).

Las dos cintas del cierre de velcro: cinta con

ganchosy cinta con fibras enmaraadas en

bucle.
http://es.wikipedia.org/w/index.php?title=Gancho&action=edit&redlink=1http://es.wikipedia.org/wiki/Buclehttp://es.wikipedia.org/wiki/Espinashttp://es.wikipedia.org/wiki/Frutohttp://es.wikipedia.org/wiki/Bardanahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/1941http://es.wikipedia.org/wiki/Suizahttp://es.wikipedia.org/wiki/George_de_Mestralhttp://es.wikipedia.org/wiki/Arctiumhttp://es.wikipedia.org/wiki/Bardanahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_minushttp://es.wikipedia.org/wiki/Xanthium_spinosumhttp://es.wikipedia.org/wiki/Arrancamo%C3%B1oshttp://es.wikipedia.org/wiki/Idioma_franc%C3%A9shttp://es.wikipedia.org/wiki/Terciopelohttp://es.wikipedia.org/w/index.php?title=Gancho&action=edit&redlink=1http://es.wikipedia.org/w/index.php?title=Gancho&action=edit&redlink=1http://es.wikipedia.org/wiki/Buclehttp://es.wikipedia.org/wiki/Buclehttp://es.wikipedia.org/w/index.php?title=Gancho&action=edit&redlink=1http://es.wikipedia.org/w/index.php?title=Gancho&action=edit&redlink=1http://es.wikipedia.org/wiki/Terciopelohttp://es.wikipedia.org/wiki/Idioma_franc%C3%A9shttp://es.wikipedia.org/wiki/Arrancamo%C3%B1oshttp://es.wikipedia.org/wiki/Xanthium_spinosumhttp://es.wikipedia.org/wiki/Xanthium_spinosumhttp://es.wikipedia.org/wiki/Xanthium_spinosumhttp://es.wikipedia.org/wiki/Arctium_minushttp://es.wikipedia.org/wiki/Arctium_minushttp://es.wikipedia.org/wiki/Arctium_minushttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Bardanahttp://es.wikipedia.org/wiki/Arctiumhttp://es.wikipedia.org/wiki/George_de_Mestralhttp://es.wikipedia.org/wiki/George_de_Mestralhttp://es.wikipedia.org/wiki/George_de_Mestralhttp://es.wikipedia.org/wiki/George_de_Mestralhttp://es.wikipedia.org/wiki/George_de_Mestralhttp://es.wikipedia.org/wiki/Suizahttp://es.wikipedia.org/wiki/1941http://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Bardanahttp://es.wikipedia.org/wiki/Frutohttp://es.wikipedia.org/wiki/Espinashttp://es.wikipedia.org/wiki/Buclehttp://es.wikipedia.org/w/index.php?title=Gancho&action=edit&redlink=1

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3. Analysis of Exist in g Techn ical Systems

The analysis of existing technical systems is one of the most important means

of generating new or improved solution variants in a step-by-step manner.

Existing systems used for analysis might include:

products or production methods from competing companies

older products and production methods from ones own company

similar products or assemblies in which some subfunctions or parts of the

function structure correspond to those for which a solution is being sought.


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Next example illustrates the derivation of function structures by the analysis of

existing systems.

This method is particularly suitable for developments, in which at least

one solution with the appropriate function structure is known,

and the main problem is the discovery of better solutions.

Figure 6.10 shows the steps used in the analysis of a flow control valve.

A typical onoff switch, showing the individual tasks of the various elementsand the subfunctions satisfied by the system.

The function structure can be derived from the subfunctions and then varied in

order to improve the product.

Anlisis de sistemas existentes.

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Figure 6.10. Analysis of a flow control valve with respect to its function structure

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4. Analog ies

In the search for solutions and in the analysis of system properties, it is often

useful to substitute an analogous problem (or system) for the one under

consideration, and to treat it as a model. In technical systems, analogies may

be obtained, for instance, by changing the type of energy used

Analogies chosen from the nontechnical sphere may prove very useful as well.

5. Measurements and Mod el Tests

Measurements on existing systems, model tests supported by similarity

analyses and other experimental studies are among the most important

sources of information.


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IntuitiveMethodsDesigners often seek and discover solutions for difficult problems by intuition

that is, solutions come to them in a flash after a period of search and reflection.These solutions suddenly appear as conscious thoughts and often their origins

cannot be traced.

The good idea is not discovered or undiscovered; it comes, it happens.

It is then developed, modified and amended, until such time as it leads to the

An industrial concern should nevertheless beware of exclusive reliance on the

intuition of its designers, nor should designers themselves leave everything to

chance or rare inspiration. Purely intuitive methods have the following

disadvantages:

The right idea does not always come at the right time, since it cannot be

forced.

Current conventions and personal prejudices may inhibit original

developments.

Because of inadequate information, new technologies or procedures may fail

to reach the consciousness of the designer.


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Velcro. Detalle de ganchos y fibras.

Velcro. Detalle de los ganchos en las espinasdel frutode la bardana(Arctium lappa)
http://es.wikipedia.org/wiki/Espinashttp://es.wikipedia.org/wiki/Frutohttp://es.wikipedia.org/wiki/Bardanahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Arctium_lappahttp://es.wikipedia.org/wiki/Bardanahttp://es.wikipedia.org/wiki/Frutohttp://es.wikipedia.org/wiki/Espinashttp://localhost/var/www/apps/conversion/tmp/scratch_6//upload.wikimedia.org/wikipedia/commons/f/f2/Velcro_loops.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_6//upload.wikimedia.org/wikipedia/commons/7/7e/Arctium_lappa01_detail.jpg

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