There used to be a time when there was a tension between testing and simulation during the product design process, but as the use of simulation software has become a necessity rather than a luxury for companies, engineers are beginning to see testing and simulation as complementary processes.
“If you want to be competitive in the industry, your company should be doing simulation somewhere,” says Steve Hartridge, director of electric and hybrid vehicles for CD-adapco, a global provider of full-spectrum engineering simulation solutions.
While not every design engineer will be running simulations, at a system level simulation software can help save money, make money, and allow designers to learn the intricate details of their products.
CD-adapco has 30 years of experience with both computational fluid dynamic (CFD) and finite element analysis (FEA) software. CFD simulation software is used to predict fluid flows and heat transfer using computational methods and has applications in industries including aerospace, automotive, meteorology, oceanography, and turbomachinery, among others.
The company’s flagship product is STAR CCM+, a comprehensive engineering physics simulation code grounded in computational fluid dynamics (CFD). It’s based on STAR CD, the company’s more “traditional” code used for internal combustion engine simulation.
“What we did with STAR CCM+ is attempt to capture all the history and development that’s in STAR-CD and put it into a new software architecture,” explains Hartridge.
Hartridge says CD-adapco prides itself on aggressive software release schedule, updating STAR CCM+ three times a year. “It’s state of the art code that lets us be aggressive with our release schedules -- that means we can get new features out to clients quickly,” he says.
To Test or Simulate
“There are certain things that testing does very quickly and efficiently,” says Hartridge. “There are things that CFD or just computational methods do very efficiently. If you use them appropriately, you can harvest the best results of both kinds of approaches.”
In the automotive industry, for example, deciding on wing shapes on the front of an IndyCar can be done by testing in a wind tunnel or with simulation software.
“In the period of a morning, you could attach 20 different wing shapes and work out the performance of those different wings and decide which one is best. What you will never find out is why that one is best,” explains Hartridge. That’s where simulation comes in.
Although CFD can move slower than testing, Hartridge says simulations give designers more insight into why a particular wing, for example, is performing the way it is.
The automotive market is currently undergoing a massive shift to electrifying vehicles. Electric and hybrid cars work by trying to recoup energy created while braking, capturing that energy and then putting it back into the system, says Hartridge. Software houses like CD-adapco are working to develop tools that can simulate those types of design challenges.
One recently-released software tool, Battery Design Studio, was developed by Battery Design LLC and is now distributed by CD-adapco. The software allows engineers to capture the internal gradients within a simulated battery cell, improving models for electric cars.
“When you use a lithium-ion battery it tends to produce heat as a waste product -- it’s a lot less than an engine would, but nevertheless it’s waste,” says Hartridge. “How well you manage those losses will affect how well your batteries operate. If you can simulate, you can get to an answer and deploy lithium-ion batteries really well.”
The Implementation Debate
Hartridge says there has been an in-house debate at CD-adapco about where in the design processes simulation tools should be best used, which mirrors the challenges that design engineers face when implementing simulation tools.
“With simulation -- and with our codes in particular -- you can apply it to the whole product lifecycle; you just apply it in a slightly different way,” says Hartridge. “When it’s upfront you have to make a lot of assumptions. As [designs] start to formalize and become more concrete, you can start to use more detail within your simulations.”
Although simulations may take more time, it can be offset by using simulation software to evaluate early designs, eliminate inefficient or unsafe approaches, and validate correct designs before building physical prototypes. All of these improvements help bring a product to market quicker.
"The things you were doing yesterday that took a month should now be done in two or three weeks by leveraging things like hardware improvements, better processes, better technology, and the code we write,” says Hartridge. “All of these should allow you to get to market sooner.”