How will future intelligent cars change component design?

As the automotive industry continues to evolve, the intelligence of vehicles continues to develop on the world's roads. The transition from internal combustion engine drive to hybrid and all-electric drive requires increasingly new and complex components, such as a range of applications in advanced driver assistance systems (such as automatic parking, or the ability to follow other vehicles while driving). How to flexibly develop solutions for emerging automotive systems is a key issue, so the way automakers cooperate with component suppliers is also evolving.

Future automotive systems require advanced sensing capabilities. Whether the sensors are in the form of cameras, radars, lidars or lasers, how these components are fixed, packaged or sealed is critical to ensure their optimal performance. The reliability of sensors is directly related to vehicle safety and public safety on global roads.

Here, we will focus on three examples of evolving automotive components: the integration of advanced functionalities, the benefits of simulation involving material properties, and the integration of vibration damping in control electronics circuit boards. We will also take a closer look at the simulation process and how smart sealing solutions can play an active role in sustainability.

Component innovation and functional integration

Taking into account the extensive use of measuring (sensing) and regulating (control) electronics in the so-called future car, sealing components for such applications must not only possess the traditional sealing function but must also meet a wide range of additional requirements and demands. Human-machine interaction and machine-machine interaction require fundamental changes in the products we deliver in the future and many factors need to be taken into account.

In the field of autonomous driving, these factors include:

• Functional integration

• miniaturization

• Material combination of multiple components

• New materials combining different physical properties

• Multi-component manufacturing process

The example of a control electronics housing is used to highlight how these additional requirements can be integrated. Such housings are usually made from thermoplastic materials, which provide a stable shell that protects sensitive internal components from environmental influences. In order to permanently fulfil this function, the material must have sufficiently high impact resistance and dimensional stability, in particular high heat resistance and excellent corrosion resistance to any media that occur, such as spray water, salt water, grease, mineral oil, fuels and cleaning agents.

Depending on the area of ​​application, other requirements such as good thermal conductivity, high electrical conductivity for shielding against electromagnetic fields, or low density for lightweight building applications may also come into play. Since such housings are often part of a larger component, these housings must have integrated connection points for mounting to the surrounding assembly. Overmolded metal bushings are a good way to mount housings on larger components in the engine compartment, for example, since they form stable connection points that can fix the housing to the larger component in the engine compartment, prevent local plastic deformation of the housing, and ensure that the assembly forces generated during assembly can be evenly transmitted and distributed to the housing.

Another key component of the housing is the elastomeric seal, which performs functions far beyond the traditional sealing function. Elastomers are usually based on liquid silicone rubber (LSR) that covers the entire interior of the housing of the control electronics, forming a complex three-dimensional flexible and elastic structure. In addition to ensuring a static seal between the housing base and the cover and protecting the interior, the elastic structure of the seal or sealing material also holds the electronic components in place by means of a cushioning element. This dampens damaging mechanical vibrations and significantly reduces the heat energy dissipated from the operating electronic components into the environment.

Figure 1: Electronic housing: Functional integration through a combination of tailor-made materials

Minimize development costs

The most important applications of elastomeric materials, especially in sealing, are based on their superelastic mechanical properties. For housings of electronic devices or sensors, the elasticity of the elastomer ensures that the sealing pressure is maintained over a long period of time and over a wide temperature range, providing the necessary flexibility when compensating for design tolerances and thus saving production costs. In many modern applications, such as in autonomous driving, it is particularly important to combine different physical material properties to achieve functional integration. In addition to elasticity, these elastomeric materials must also have other additional physical properties:

• Super elasticity

• flexibility

• Viscoelasticity

• Mechanical damping characteristics

• Optical transparency within a specified frequency range (or wavelength range)

• Electrical conductivity

• Thermal Conductivity

• Insulation or magnetic

These combinations of properties can be achieved through the synthesis of new polymer materials specifically to meet specific requirements. However, the development of such materials is time-consuming and costly, requires expertise and synthesis equipment, and the properties achievable may still be very limited.

Often, the desired additional material properties can be obtained more efficiently by incorporating special fillers into the elastomer matrix - a method well known to elastomer manufacturers. Depending on the type of filler, particle size distribution, particle shape and particle concentration, the desired material properties can be tailored to customer needs while simplifying a process that is usually labor-intensive.

Simulation can support the development of such materials with new properties and offers excellent opportunities to calculate and predict the effect of fillers in the polymer matrix. This accelerates the development of such multiphase or layered materials. Based on existing materials or ideas for new materials, a model of the material structure is created. Based on this so-called representative volume element (RVE) and the inherent properties of the components (matrix and fillers), the desired properties, such as thermal conductivity or elastic behavior, can be calculated using finite element analysis. As a result, the composition of new materials can be optimized at an early stage, which can significantly reduce subsequent laboratory work.

Figure 2: Simulation supports the development of layered materials with new properties

Ensure vibration damping of control electronics

Additionally, for specific applications, the viscoelastic material properties of the elastomer play an important role, especially the vibration damping properties. Certain vibration damping properties of the material may be required to prevent the component from vibrating too much during driving and under resonant conditions. An example of such an application is the integration of vibration damping elements into a printed circuit board for electronic circuits. In the following example, the circuit board is geometrically structured in order to provide the necessary flexibility in the overall design for the specific application. The integrated LSR structure provides the necessary flexibility and at the same time has a damping function to prevent damage caused by amplification of the vibration amplitude under resonant conditions. The sensing and/or control electronics are installed in a housing and it is necessary to mechanically decouple them from the housing and the vehicle vibrations in order to reliably perform their function.

Figure 3: Effects of geometric design and material properties on resonance characteristics (Simulation results of sensor electronics)

Consider simulation early in the product development process

The development of new components and parts for the next generation of vehicles can be an expensive and time-consuming process. This is where working with a specialist component supplier who is well versed in simulation, in order to eliminate the need for multiple single-mode development, associated testing and analysis, can significantly speed up time to market while reducing capital expenditures during the development phase and beyond.

If we look at the simulation process itself and how it facilitates the development of new parts and their components, the ultimate goal is to design, visualize and optimize virtual concepts and then support their transformation into real products and processes. By combining CAD tools (which provide the geometry) with simulation tools to create virtual models of specific parts, it is possible to accurately calculate their functions before building them.

After CAD, as part of the modeling phase, we have to assign specific material properties to the different parts of the component. Therefore, a series of tests must be performed and then the necessary materials modeled. This is an important prerequisite that is usually only available through professional component manufacturers.

For many applications and products, experienced suppliers use their own special materials, so customers cannot obtain detailed material information from outside. Therefore, suppliers need well-equipped internal teams that are capable of undertaking all testing and mathematical modeling of these simulation materials. In turn, these teams can also provide testing and modeling services to customers, providing additional support throughout the process.

When it comes to the function and design of the components, structural-mechanical calculations based on the finite element method allow the properties of the sealing elements to be fine-tuned and their performance and design to be optimized, so that the initial draft can be quickly developed into a convincing design. Many aspects and influencing factors need to be taken into account - first of all, the given installation space, the influence of the applied loads (such as displacement, pressure or temperature), and the properties of the materials used. The most important thing is to ensure the function and sealing integrity in the temperature range of -40℃(-400F) to +150℃(3020F), while taking into account all design tolerances.