As discussed in Part 1, engineers are tasked with designing electrical components that can withstand the increased thermal and mechanical loads required of today’s ever-more-powerful electronics. Sometimes these are entirely new designs built from the ground up, and subjected to holistic testing and prototyping during the R&D phase. But often, manufacturers seek to merely tweak specific components within an existing design, and either don’t properly anticipate the effects that small changes can have on thermomechanical balance and product longevity, or need a way to predict these effects without going through a lengthy and expensive prototyping process. Multiphysics simulation tools can be invaluable assets in both situations.
Early Stage Partners
Traditionally the thermal design of electronic assemblies has been left to a relatively late stage in the design processes when much of the electronics and mechanical design is nearing completion. This has led to a lot of late-design rework, and often further iterations, due to problems found during physical prototyping. Consequently it can mean design costs skyrocket, products are frequently late to market, and there is not enough time for exploring better design approaches and optimization strategies in the upfront design phase where simulation has the most impact.
Using Multiphysics simulations that account for conduction, convection and radiation, engineers can evaluate different key metrics, including rate of heat transfer and junction temperatures, and can visualize the distribution of heat in critical areas. Engineers can easily test their designs without wasting valuable time and resources. Simulation is a fast and cost-effective method of evaluating and optimizing the heat transfer processes in a wide range of prototype geometries and working conditions.
Ensuring Design Longevity
Multiphysics software tools also provide the ability to perform thermomechanical stress and fatigue analysis, thereby calculating the lifetime of electronics components. These simulations include heat generated by the component, air flow around the component and radiative heat transfer from the component. Once the thermal environment is calculated, the effect of temperature changes on the component stress can be determined. The stress and strain then form the basis for calculating the component lifetime using fatigue damage models. This approach enables engineers to design electronics with desired lifetimes.
One example of this type of analysis is the fatigue cracking of solder in ball grid arrays (BGA). This failure mode is often driven by a combination of thermal gradients and mechanical constraints. AltaSim has conducted these analyses to help mechanical engineers better understand the factors producing the failure mode and methods for mitigation. These analyses are often not done during the initial design phase, but have been shown to be extremely helpful when BGA failures develop during prototyping.
Multiphysics software simulation offers an exceptional opportunity for the electronic components design industry. Uniquely versed simulation engineers can seamlessly plug into the existing engineering capabilities of a company, providing rapid, high-quality virtual prototypes of their design concepts, and identifying potential problems and solutions. The resulting efficiencies and cost savings make simulation a smart choice at multiple points during the design process.