• Document: THERMAL ANALYSIS. Overview
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W H I T E PA P E R THERMAL ANALYSIS Overview In this white paper we define and then outline the concept of thermal analysis as it relates to product design. We discuss the principles of conduction, convection, and radiation using real-life products as examples. We will also describe ways to perform thermal analysis, specifically how you can use design validation software to simulate thermal conditions. We will also list the desired capabilities in thermal design validation software and demonstrate through examples how you can solve design challenges using Dassault Systèmes SolidWorks Corp. products. Introduction to thermal analysis To reduce product development cost and time, traditional prototyping and testing has largely been replaced in the last decade by a simulation-driven design process. Such a process, which reduces the need for expensive and time-consuming physical prototypes, allows engineers to successfully predict product performance with easy- to-modify computer models (Figure 1). Figure 1: Traditional versus simulation-driven product design processes Design verification tools are considered invaluable in studying such structural problems as deflections, deformations, stresses, or natural frequencies. However, the structural performance of new products is only one of many challenges facing design engineers. Other common problems are thermally related, including overheating, the lack of dimensional stability, excessive thermal stresses, and other challenges related to heat flow and the thermal characteristics of their products. Thermal problems are very common in electronics products. The design of cooling fans and heat sinks must balance the need for small size with adequate heat removal. At the same time, tight component packaging must still ensure sufficient air flow so that printed circuit boards do not deform or crack under excessive thermal stress (Figure 2). Figure 2: Electronic packaging requires careful analysis of how heat produced by electronic components is removed to the environment. Thermal Analysis 2 Thermal challenges also abound in traditional machine design. Obvious examples of products that must be analyzed for temperature, heat dissipation, and thermal stresses are engines, hydraulic cylinders, electric motors or pumps—in short, any machine that uses energy to perform some kind of useful work. Perhaps less obvious candidates for thermal analysis are material processing machines where mechanical energy turns into heat, affecting not only the machined piece but also the machine itself. This situation is important not only in precision machining equipment, where thermal expansion may affect the dimensional stability of the cutting tool, but also in high power machines such as shredders, where components may suffer from excessive temperature and thermal stresses (Figure 3). Figure 3: Potential overheating of an industrial shredder is an important consideration in the design of its transmission and bearings. As a third example, most medical devices should be analyzed for thermal performance. Drug-delivery systems must assure proper temperature of the administered substance while surgical devices must not subject the tissue to excessive thermal shock. Similarly, body implants must not disrupt heat flow inside the body, while dental implants must also withstand severe external mechanical and thermal loads (Figure 4). Figure 4: Dental implants must not affect thermal conditions of the surrounding tissue and must also withstand thermal stresses. Thermal Analysis 3 Finally, all electrical appliances such as stoves, refrigerators, mixers, irons, and coffee makers—in short, anything that runs on electricity—should be analyzed for thermal performance to avoid overheating. This applies not only to consumer products that run off AC power, but also to battery-operated devices such as remote-controlled toys and cordless power tools (Figure 5). Figure 5: Adequate cooling of a high capacity battery on a cordless tool requires understanding the thermal conditions. Using design validation for thermal analysis All of the above thermal design problems and many more can be simulated with design validation software. Most design engineers are already familiar with this approach for structural analysis, so expanding its scope to thermal analysis requires very little additional training. Structural and thermal simulations are based on exactly the same concepts, follow the same well-defined steps, and share multiple analogies (Figure 6). Furthermore, thermal analyses are performed on CAD models the same way as structural analyses so, once a CAD model has been created, a thermal verification can be completed with very little extra effort. Thermal analyses can be

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