QMT Features: November 2012
No more smoke and mirrors
New-generation technology is simplifying simulation for product designers, says Erwin Burth of Autodesk

Even today, simulation skills are often regarded as some kind of wizardry, enveloped in intricate formulae and only accessible to those in the know. Yet, being able to simulate real-life performance before manufacture, can eliminate many of the significant risks associated with the launch of a new product and prevent expensive mistakes.

Much of the mystery surrounding simulation is due to its complexity and the need for specialist expertise.  However, in business terms this translates as expense. Only larger companies can afford the niche systems required and to hire experts to develop methods which apply to their particular products.  It is also often carried out in an inefficient serial design-prototype-test-redesign cycle. The alternative is outsourcing, but this can be costly too. Consequently, as a rule, simulation tends to be reserved only for certain products.

But still, designers and engineers across the manufacturing sector make key design decisions about weight, strength and dimensions every day, relying on ‘rule of thumb’ or traditional calculations using handbooks. As a result, parts are often ‘over-dimensioned’, resources wasted or materials that are not up to the job chosen mistakenly in a bid to cut costs.

There have been attempts in the past to introduce simulation skills to non-experts, but often these tools were only able to carry out simple linear analyses on single components and the simulation specialists dismissed them as over-simplified. There were examples of success, but only for those prepared to invest in training, standardising processes and generally working hard to force the technology to fit their needs.

But recently, several factors have come together to create a breakthrough. The development of an intelligent 3D digital prototype of a product which can be visualised and then tested as if it were the real thing can have a significant impact on product cost, quality, reliability and development time.
The integration of multi-physics simulation technology with this digital prototype makes simulation-driven design, early in the product development process, a reality.

This transformation is being spearheaded by Autodesk, whose extensive portfolio of design software products including AutoCAD and the digital prototyping tool, Autodesk Inventor, is widely used across the global manufacturing industry. The company has invested over $500 million in acquiring simulation technology innovation to support its vision of “democratising” its use. While recognising that the experts will still have a role, Autodesk believes that its new simulation software products make the technology available and accessible to all types and sizes of business.

For example, Autodesk Moldflow is already being used by engineers at Primera Plastics, producer of custom plastic parts for global customers including furniture manufacturers and automotive original equipment manufacturers ( OEMs). Here, engineers run a range of simulations using the software to study the flow of melted plastic, evaluate various running systems and gate configurations, determine the most efficient cooling systems and predict volumetric shrinkage. It can also use simulations to predict how long it will take for a plastic part to reach ejection temperature and how long it will take for a part to warp.

This is important to the business because the cost of injection moulding often makes up a major part of the total cost of manufacturing – in some cases up to 75 per cent.  The simulation software also helps find and fix potential defects such as short shots, air taps and weld lines well before manufacturing begins. “We can save months of production time and significant costs,” Primera Plastics project engineer, Scott Leatherman reports.

Similar benefits are coming to light using other simulation technology – such as Finite Element Analysis (FEA) and Manufacturing Event Simulation (MES) - as an integrated part of a complete digital prototyping solution. For example, snow vehicle manufacturer, Tucker Sno-Cat® Corporation, uses these to validate the motion of parts and to validate the quality of its designs. Rather than outsourcing FEA on its roll-over protective structures, for example, it can now perform the analysis more efficiently and cost-effectively in-house. Consequently, it has slashed the time and cost for design validation by 50 – 60 per cent.

These figures alone tell their own story. Recently, however, a further technological development, , has begun to break down further barriers to universal adoption. As product complexity grows, increasing computing power is needed to perform multi-physics analyses, often exceeding the scope of the desktops and workstations used by most designers and engineers. But, the good news is that cloud technology can address this shortfall.

Now, engineers no longer have to spend time simplifying geometry prior to analysing a design.

Once they have logged on, the software automatically acquires all the appropriate geometry, limits and parameters and so on and transfers the data to the high performance computing in the cloud. This performs the meshing, executes the necessary solvers, runs the appropriate post processor and then returns the results to the user, who has been able to continue with other tasks on their own computer in the meantime.

The infinite computing power available in the cloud means that users can now perform complex multiple pre-processing or simulation tasks in parallel, enabling them to quickly study a large number of design alternatives. The analysis of design variations can run on a large number of computers in the cloud. In almost the same amount of time that a single analysis would take on a desktop, the cloud delivers results for all iterations, enabling the engineer to choose the optimum version.
As cloud computing is purchased on a “pay-as-you-go” basis , these methods also dramatically lower the costs of simulation, making it more widely available to all sizes of business. There is also no lengthy implementation process – only the need to purchase pre-paid “cloud units” which give access to a range of software products without the need for specific licences.

These include a range of mechanical and multi-physics simulation tools, Computational Fluid Dynamics (CFD ) and Moldflow analysis, plus other more specialised products such as a wind tunnel simulation tool available as a plug-in for Autodesk Alias surfacing software. This provides industrial designers with flow and wind pressure results, which update almost in real time in response to changes in wind direction and speed. There is also a simulation app for iPads (Autodesk ForceEffect, a mechanical statics application) and even a physics-based mechanical simulation game that runs on an iPhone.

Being able to predict how a product will work in the real world , without having to build costly, time-consuming physical prototypes or wait for results from expensive consultants is a real advantage.  Ultimately it will lead to better products brought to market faster and for less cost.l
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