Formula 1: Multiphysics Simulations for Performance

It is truly a modern mechanical miracle that Formula 1 race cars can "keep it together." These machines travel at breakneck speeds, perform hairpin turns and create enough explosive acceleration to outpace the competition – all while looking elegantly powerful. 

Still, the truth is these vehicles are pushing the edges of technology to achieve performance metrics that were previously thought impossible. These machines are true marvels of engineering; however, pushing the boundaries of what we know to be possible can often have disastrous consequences if not designed with care.

Formula 1 car design requires the analysis of many different system components. Various Multiphysics Solvers can help engineers perform create optimized mechanical designs.

So Many Things CAN Go Wrong!

Imagine this—scenario one. A driver is barreling down the track. He's gaining on the lead racer. He has a sharp turn coming up, but he knows he can overtake the leader if he can gain more speed. He inches past him and performs a dazzlingly sharp turn. The aerodynamic forces suddenly cause the wing to vibrate at the structure's resonant frequency, and the aerodynamic forces snap off the front wing. At this point, the driver has no aerodynamic control structures and quickly loses traction with the ground., careening to a stop. This is an example of structural failure due to dynamic loading from fluid-structure interactions. 

Even worse, scenario two. Imagine the driver has been using his brakes a bit more than usual. This track has sudden sharp turns. After a certain point, the disk brakes have heated to a degree where the stiffness coefficient has reduced significantly, thereby lessening the braking power. The driver slams on the brakes and… nothing happens, leading to a possibly violent accident. The phenomenon described here occurs as different materials have different physical properties over different temperatures. 

Lastly, scenario three. Imagine a surge in power causes a component in the engine control unit to overheat and fail due to thermal stress in a soldered joint. Specifically, this is due to the Coefficient of Thermal Expansion (CTE) mismatch between components within a Printed Circuit Board (PCB). This failure can cause the electrical systems in the F1 car to malfunction, leaving the vehicle incapable of racing. 

Ultimately, these vehicles operate on the edge of tolerable forces and temperatures to produce the most speed and performance. Each issue described (and more) are genuine phenomena that can occur if a single component of the vehicle is designed improperly. The rigor of analysis required by engineers ensures that a robust mechanical design process needs to be established to provide optimal performance. 

Mechanical Design: Optimizing and Balance

Imagining the scenarios above shows just how fragile formula cars can be. Engineers clearly need to make the components of the vehicles strong enough to endure all the extreme conditions the car will face within a race environment. Unfortunately, for engineers, the problem is not as simple as "design the strongest car." The vehicles must race and race well.

In mechanical design, engineers find themselves in a difficult position of optimizing to competing constraints. In practice, a car designed to maximize the strength of components would be way too heavy to compete. At the same time, a vehicle that only focuses on race performance would never survive more than a few laps! The art of the sport (and engineering in general) is finding the optimized balance between competing design constraints. 

Multiphysics Analysis

While experimental testing can be a valuable tool in mechanical design, engineers can use multiphysics simulation software to save time and money compared to building and testing prototypes. There are several domains within multiphysics simulation. The sub-disciplines most pertinent to the design of F1 cars include:

• Computational Fluid Dynamics
• Structural Analysis
• Thermal Analysis
• Electromagnetic simulation. 

While these disciplines of multiphysics simulation all address different problems, they all operate similarly "under the hood." 

Essentially the physical processes these disciplines concern themselves with are modeled by what is known as partial differential equations. Coming up with an exact solution to partial differential equations can often be very difficult (if not impossible in some instances). In these cases, determining a reasonably accurate approximation to a given equation is often much more straightforward. 

That is what each of these Multiphysics Solvers does. At a high level, these solvers work by discretizing a geometric surface and solving these PDE approximations at each discretized node. The multiphysics design workflow includes:

• Designing geometry for a component
• Cleaning the geometry to be "watertight" (no holes or irregularities)
• Discretizing the geometric grid (known as meshing)
• Initializing the solution/setting up the solver, and finally visualizing the results. 

Each part of the workflow can be tedious and clog up a rapid iteration design process. For fast and accurate design analysis, designers need a work platform that can handle each sequence of the design process accurately and efficiently.

Cadence Multiphysics Solvers

Cadence Multiphysics Solvers include a suite of analysis tools for tackling the different problems we explored and more. Cadence Fidelity is a computational fluid dynamics solver that allows for the analysis of the aerodynamic performance of the vehicle. It also manages the dynamic modes of various structures and how the aerodynamic forces affect dynamic loading. This CFD platform also allows for the analysis of heat transfer and exchange to understand the thermal management of various components. 

Cadence Celsius is a thermal solver specifically designed to analyze different electrical components' electrical and thermal properties, including Integrated Circuits (IC) and Printed Circuit Boards (PCB). The solver allows for the simulation of power surges or fatigue cycling that can be responsible for the CTE mismatch-induced failure described earlier. 

For the design of the ICs and PCBs, Cadence also offers Cadence Clarity. This 3D electromagnetic solver allows engineers to design complicated interconnections for these different electronic packages. 

Multiphysics solvers are critical at every step of the mechanical design process for an F1 car. By investing in robust platforms like those Cadence offers, designers can save precious time and resources.