Does simulation deliver all that it promises?

Partly art but largely science, simulation allows users to manipulate 2D and 3D CAD models to simulate the physics of how a structure or a process might form in a virtual/digital environment. But like most technology, it is not without its challenges — working out a favourable return on investment, upskilling employees and deciding how much of the design process simulation can replace. There is currently a range of simulation software on the market, including some of the most popular — Femap and NX Nastran — for use in structural, mechanical, thermal and fluids finite element modelling and analysis. Other products cover FE modelling and simulation (NX Advanced Simulation) and injection moulding optimisation (Moldex3D and winLIFE).

The main benefit of simulation is it reduces costs and time as it lowers the number of physical prototypes required. It also reduces errors in the design process. Vernon McKenzie, director at EnDuraSim, told PACE the cost benefit of simulation for high value products such as airplanes and spaceships are obvious — situations where a prototype would be extremely costly or not possible. When working out the cost benefits of lower value products such as small mechanical products and structural products and process, the same ROI is yielded. The only difference is the model and equation are smaller.

The cost benefit equation has several inputs. For example, comparing the cost of a prototype (including material and labour costs) and the cost of revising the physical prototype if an error is found to the cost of running numerous iterations in simulation software.

“Even though the simulation might not get it exactly right because it’s fairly complex physics, it gives [users] more insight into what parts of the product is doing the work when the … test is performed,” McKenzie says.

He believes the cost of the software and computing power required is rela tively low. The main financial expense is hiring either a consultant to carry out and analyse simulation results or employing or training an engineer in- house to carry out those tasks.

According to McKenzie, it can take from 12 to 18 months for a person to become completely competent in simu lation capabilities. The skills shortage has exacerbated this time. “We know of customers who will spend 12 to 18 months trying to find people who are experienced in this area. They might find a graduate who has a little experi ence in this sort of technology at univer sity. That means they then go through the process of training people to become experts in this area,” he says.

EnDuraSim can train engineers on specific jobs. This method of training can give users a quicker learning process, but McKenzie concedes it can still take a while for users to become fully competent .

“For us, that’s our biggest concern for customers getting value for money — whether they should be getting us to [consult] or whether they should be developing this expertise in-house and making the effort to do this sort of work themselves,” McKenzie says.

He believes companies should be developing the expertise in-house, particularly if engineering design makes up a large part of their company and where intellectual property is at stake. “I don’t believe they should be outsourcing the simulation aspect of that,” McKenzie says. “I think they really should make the decision that this is technology that they should be developing expertise in and using the advantages of simulation within their own organisation.”

The cost benefits may not always be immediate or even quantifiable. GRG Consulting Engineering has been using simulation software for around 2.5 years for the analysis of steel structures, tank analysis, structural connections and mechanical components.

“At this point in time, I do not believe there has not been significant cost savings,” says Graeme Klee, senior design at GRG Consulting Engineers. “However, GRG Consulting Engineers do not use the software package on a day-to-day basis and as such, the biggest challenge due to the lack of regular use is [it is] difficult to be conversant with the diversities of the software and the various options available in its dialogue boxes. [However], the software has broadened GRG’s scope to a wider range of more complex design projects that can be undertaken, therefore exposing GRG to a broader engineering market.”

A big advantage of simulation is it provides insight into several aspects of product development — which parts didn’t work, but also aspects which did work. This allows engineers to not only assess errors, but also to look at whether areas have been over designed or where they could be better optimised. These insights may not be gleaned from phys ical tests. Although simulation may seem most suitable for large companies, EnDuraSim’s clients range from one person organisations to mid-level companies with 15 staff to much larger companies. The key for smaller compa nies making the most of simulation comes back to expertise and whether they choose to develop it in-house or use consulting companies.

“That decision is not a trivial deci sion because it involves either a high cost in terms of a person they’re going to employ and how much time that person will be used in that particular area of their expertise, or if they develop up a person, how long is that going to take?” McKenzie says.

Simulation has theoretically meant prototypes aren’t required, but McKenzie is adamant this process should not be entirely eliminated. He recommends a physical testing program to calibrate simulation processes to provide external validation of simulation results. Otherwise, the simulation will work on a user putting in all information correctly, which may not always occur. Without checking simulation results, the risk of errors at the end increases.

Despite McKenzie’s warnings, it seems the industry is heading in this direction. Several years ago, Toyota announced it would increase its reliance on designing cars in a digital environ ment and cut back on prototypes. The company was this year plagued by recalls, with an estimated eight million cars recalled globally.

“The connection between the prac tical, real world conditions and how the product operates needs to be preserved, otherwise there is that risk that the product is not going to be as good as it needs to be,” McKenzie says. “We hope that organisations that are sensible enough to invest in digital simulation technology take heed of our message, which is — don’t completely disconnect this from the physical world.”