As mentioned in the earlier article, modelling and simulation go hand in hand as far as product development in concerned. Both provide tools to gain insights into the behaviour and features of the product or system that is being developed. While models show how a product or system should look and behave, simulation is used to check if it will really behave the way it is supposed to be. Real life objects are exposed to varied conditions. Models are abstract, simulations provide tangible results. It is essentially the imitation of real life system. Take the case of a simple plastic bucket. While product modelling allows designers to create a nice looking, right sized and shaped bucket, it is simulation that answers questions like ‘what is the maximum water temperature the bucket will sustain without deforming?’ and ‘how strong the handle must be to sustain the weight of 25 litre of water?’. In other words, simulation is needed to handle the practical aspects of product development. Having understood the difference between modelling and simulation, let us turn our attention to simulation in detail. Again, our focus will be limited to simulation for product development.
Why Simulate?
Simulation is essential for product development as it saves time and money while ensuring better product performance and robustness. Take the previous example of the bucket. If the manufacturer opts for a particular kind of plastic without simulating, there is a strong possibility that the bucket may not be able to sustain water temperature, pressure, or the weight of the water. The handle may give in and break if it is not designed and developed from proper material. Since the properties of various types of plastic are known, simulation helps manufacturers choose the right plastic without having to manufacture real buckets and then testing. What if someone decides to use the plastic bucket to store viscous oil? Will it sustain the weight? With proper simulation, manufacturers are able to tell consumers exactly how much weight the bucket can handle without having to experiment with real oil. What we are dealing here is a simple bucket. Real life objects are much complex than a simple bucket. An automobile, a crane system, an aeroplane or military missile system are examples where modelling and simulation is highly needed. Each of these objects consists of literally hundreds of components that work together as a single mechanism. Even if one component breaks, it can result in the failure of the entire mechanism. Simulation is needed to evaluate and identify how to make the mechanism perform without breaking in real life without actually having to develop it first. Thanks to today’s computers and specialized software like that from Altair, simulation has become relatively easily. In fact, when we mean ‘simulation’ today, it invariably alludes to ‘computer simulation’. Deep analysis of complex, real life objects are simply not possible without proper modelling and simulation. Will an object sustain a fall from 5m? What will happen if an aeroplane flying at a speed of 575 km per hour runs into turbulence? Will a ship survive strong gales of 40 knots or above? Simulation and modelling software like Altair Flux™, AcuSolve™, FEKO™, OptiStruct™, Radioss™ and Activate™ make it possible to answer all these questions accurately without having to expend money developing actual products first. It is one of the most powerful tools available to decision makers responsible for the design and operation of complex processes and systems. Simulation software makes possible the study, analysis and evaluation of situations that would not be possible otherwise.
Firstly, simulation allows the user to experiment with different ‘what if’ scenarios and thus helps the design team to focus on creating what is ‘right’ for the system, process or object without worrying about cost constraints. Secondly, it allows them to mull over something by seeing it repeatedly (like watching simulation videos) in case something has gone wrong in the design process. They can then simply tweak some parameters and experiment all over again. In fact, one of the most important uses of simulation software is to manipulate and tweak the parameters involved in the model in order to try and get an optimal solution – at least at the prototype stage. Since it tries to emulate real world as closely as possible, simulation has proved to be an invaluable tool for manufacturers, designers and engineers to stay ahead in the competitive world.
Types of Simulation
When it comes to engineering products, there are many types of simulation that need to be undertaken. A few standard simulations include Crash Test, Drop Test, Structural analysis, Product Design Optimization, Multi-body dynamics & Kinematics, Thermal analysis, CFD ( Computational Fluid Dynamics) analysis, Electromagnetic Analysis, Mould flow analysis, NVH analysis ( Noise & vibrations), sheet metal forming, linear, and non-linear and static analysis. Besides these, there are many types of simulation that are undertaken as and when needed.
Simulation Analysis
How do you know if a simulation is correct? To do that, there are certain norms that have been established, and some steps that need to be followed.
Model verification: The first step before simulating a model is to verify that it has been implemented properly and that it accurately represents the design teams description and specifications
Validation: It is not necessary that a model that is verified is valid. Validation is the process of comparing the model’s implementation and its associated data with the developer's conceptual description and specifications.
Analyze and experiment: Verify the simulation model by comparing its result with the real-time system. Reiterate simulation by changing parameters and comparing the results to find the optimum system solution. This process is called simulation experiment wherein input variables ofa simulation model are changed in order to observe and record performance changes.
There is no hard and fast way whereby you can say that a simulation has been successful. At best, simulation is an empirical method for validating a model. The success of simulation depends upon the success of the system or the product, and its acceptance by the users when it is actually manufactured.
Is Simulation the Answer to Every Product?
Simulation is similar to other engineering disciplines. It requires training and experience to become competent. True, highly sophisticated tools like Altair Compose® allow even someone without engineering background to simulate, but knowledge and experience are necessary to get results that really matter. Again, let us take the case of an aeroplane. Airliners would be happy to accommodate as many people as possible in a single flight. Simulation software too will provide a solution if the airliner says they want to create an airplane that carries 2000 people. However, an experienced engineer will point out that the runway length needed for such a craft to take-off and land does not exist anywhere in the world yet.
Importance of Simulation Software
We would be nowhere in modelling and simulation today without computers. Till a few of decades back, mathematical modelling and simulation was the prerogative of those with access to super computers. Modern computers have enough processing power to bring the advantages of simulation within the reach of even small companies and individuals. Simulation software not only reduces time; the parametric nature of most of the leading software today allows coherent study of the model under consideration. There are numerous simulation software packages available today, ranging from free to thousands of dollars. The suitability of a simulation software depends upon its modelling flexibility, modelling structure (hierarchical v/s flat; object-oriented v/s nested), GUI, code libraries, statistical capabilities, ease of use and support. Products like Altair Flux, AcuSolve®, FEKO®, OptiStruct®, Radioss® and Activate are industry standard simulation packages that satisfy the above criteria. Like most other things in life, you get what you pay for. To develop a fully functional and optimal product in least time, it is better to invest in industry standard simulation software that provides accurate simulation. The results will be worth it!
Summary
While simulation is extremely important for product development, it is equally important to invest in a simulation software that produces accurate results and gives engineers a free hand in experimenting with various design parameters.