As discussed in our previous article, “Lightweight Design in the Automotive Industry – the power of Simulation”, we discussed the need for simulation as alternative materials and design methodologies are used to maximize driving efficiency and fuel economy. In general, simulation is a practice that is best incorporated throughout the design process, from conceptualization, to prototyping to pre-production development. Let’s review the historical use of simulation, new tools available to industrial designers and how to leverage simulation for reducing production costs and time-to-market.
First, a historical perspective on simulation: for decades simulation was this nebulous art/science that could only be conducted by those with “Ph.D.” after their names. Taking a prototype through the wind tunnel has always been a significant cost. The more iterations required, the more simulation testing, the higher the cost of development. Ideally, the more you can simulate the better off you will be, but how can we afford to do this? How does simulation interrupt the process? Is there a way to continue making progress while simulation is being done?
There are many new tools available to offer industrial designers the ability to simulate independently. Professional simulation is still a necessity, but with these new tools designers can conduct some basic testing and analysis throughout the design process without having to stop what they are doing, and duplicate the resources required in order to do so.
Computational Fluid Dynamics (CFD) offers testing in two categories: aerodynamics and heat transfer. The use for aerodynamics is pretty straightforward, limiting drag is one of many ways we can improve efficiency. Determining how the lines and curves can be tweaked to allow air to flow over and under [JH1] [SS2] the auto obviously aides designers by providing immediate, actionable feedback. The ability to make adjustments and test in real time allows designers to be more accurate earlier in the design process.
Another application for CFD testing is heat transfer. This is especially important in mechanical engineering. CFD simulation of the mechanical components allows you to properly test the impact that heat can have on the performance of particular parts. Say for example, plastic is being used to replace a traditionally steel part, but can only handle a certain amount of heat. CFD analysis can identify points of failure or areas that have to be insulated to protect certain parts from high amounts of heat. [JH3] [SS4] Not only can it cause a part to fail, but it could also cause warpage depending on the heat/material used, or be dangerous if the hot parts are too close to a person.
Finite Element Analysis (FEA) is often used for as stress-testing parts. [JH5] [SS6] As an example, bumpers and siding in the event of collision is a common application for this type of simulation. This is especially important as alternative materials are used where there is limited experience for specific parts. Often times components need to factor in both thermal stress as well as pressure loading due to normal use. Although engineers know the mathematical formulas to calculate key performance, incorporating simulation allows an algorithm to validate the design or identify points that require modification.
In recent years, the tools mentioned above have not only become available to designers and engineers, but have become affordable as well. There is no real replacement for crash-testing and wind tunnels, but a lot can be done in earlier phases of automotive design to reduce the number of times these real-world simulations are required. Simulating early and often can help identify issues early, reducing the amount of rework that inevitably flows downstream. Similar to clay models and 3D rendering, these simulation tools improve the design and communication process, helping to reduce the number of iterations of the traditional tried and true methods.