Historically, engineers had to apply some degree of simplification to their simulations to meet product deadlines while improving those aspects of performance most valued by users. This often meant focusing on the single most important physical phenomenon affecting the product.
For example, designers of Formula 1 cars traditionally devoted resources to improving aerodynamics via computational fluid dynamics (CFD) simulations. Designers of construction or agricultural equipment used mechanical simulation software to optimise a product's ability to withstand heavy forces. Manufacturers of printed circuit boards invested the majority of their efforts in ensuring signal integrity.
This historic focus on a single physics yielded useful insights into critical product characteristics, often resulting in significant performance gains and at a lower investment of time and money than traditional experimental and physical prototyping methods.
But, as competitive pressures have increased and consumers have become more sophisticated in their demands, today it is rare to achieve the best-possible product design when optimising a product’s response to a single physical condition. To understand every physical parameter at play, and accurately predict if the product can perform well as a result, all the relevant physics need to be considered.
Being able to simulate all physics at the same time, and perform parametric optimisation using multiphysics results, allows engineers to gain important insight into product performance, target optimal designs faster, and release products to market earlier.
As a result of applying these tools and processes, today’s Formula 1 engineers gain new insights into how to balance aerodynamics with high power, structural integrity and low weight. Heavy equipment manufacturers eliminate not just structural weaknesses, but thermal stresses that can cause part deformation and failure. And electronic product designers go well beyond investigating EMI, focusing on how heat affects multiple components and solder joints.
The challenge of product complexity
In virtually every industry, multiphysics studies enable engineers to address an even greater challenge: the growing complexity of their product designs.
Modern product development trends, such as increasing power density of electronic devices, product miniaturisation across industries, consumer demand for smart products, growing use of advanced materials and increased emphasis on sustainability, have created special challenges.
Densely packed electronics need adequate cooling, which is often provided by fans and heat sinks that must be carefully engineered. Chip manufacturers need to understand the impact of heat on the circuit board and solder joints — especially thermal deformation caused by temperature fluctuations — to develop robust electronic products that don’t fail under on-design or off-design conditions.
Medical devices, which are increasingly designed for operation at nanoscale, must perform flawlessly in the presence of strong fluidic and body forces. The individual patient’s geometry, blood vessel contraction, blood flow patterns and characteristics of surrounding internal organs must all be accounted for simultaneously when predicting the behaviour of a particular device or procedure.
New advanced composite materials comprise layers of fibres, some of which have unique thermo-electric properties. Car bodies and airframes made of such materials must be optimised not only for thermo-electric performance, but for aerodynamic performance, vibration response, energy efficiency and long-term reliability.
These and other trends make it more and more challenging for engineering teams to answer essential product development questions:
-What are all the potential sources of product failure?
-How can we achieve the best trade-off among multiple performance requirements?
-Can the specified materials withstand all the expected fluidic and mechanical forces?
-Is the amount of cooling sufficient, given the potential for thermal transfer among components?
-Can this product be produced time- and cost-efficiently — while also minimizing material, energy and waste?
Growing design complexity is making it harder to answer these questions with absolute confidence. At the same time, it has never been more crucial to eliminate product failure and deliver reliable performance.
Enter Multiphysics
Multiphysics simulation, once considered an advanced engineering strategy used only by experts, is becoming a standard part of today’s product development toolkit in many industries, in order to answer these questions. By using multiphysics studies to predict and verify product performance under a wide range of operating conditions and accounting for the effects of various physical forces, engineering teams can eliminate many sources of real-world product failure.
While multiple physics historically have been considered via a series of unconnected single-physics studies — focusing separately on fluids, structural, thermal and electronics effects — engineers today increasingly recognize that the interactions among physics are significant enough to require deeper investigation.
Engineering teams often begin to link multiple physics by transferring data from a previously completed physics simulation or experiment, for use as either initial or boundary conditions. Results transferred as boundary data one time — or at multiple times during the simulation — form the basis of a one-way multiphysics analysis.
Sometimes, the physics are inherently strongly coupled, and important interactions cannot be captured with sequential simulations. Examples include designing valves, modelling deformable bodies in the presence of aerodynamic forces, and analysing conjugate heat transfer. In these cases, concurrent simulations that exchange data at specified intervals — called two-way co-simulation — are needed to solve multiple physics simultaneously while considering the tight interactions of all physical forces.
R&D teams can choose the multiphysics coupling that gives them the right amount of insight to solve the problem that they have today — as well as the ones that they need to address in the future.
Many engineering teams were reluctant to cross the digital threshold and embrace the power of simulation when it was first introduced, yet today simulation has become a standard engineering practice in every industry.
Multiphysics simulation represents the future of product engineering, soon to become an industry standard as development teams seek to manage complexity, increase confidence, and further drive time and costs out of both the design cycle and production processes.
Chris Wolfe is lead product manager, ANSYS Multiphysics