# Thermo-Mechanical Coupled Analysis of Electric Vehicle Drive Shafts
## 1 Introduction  
As concerns over climate change and the stability of energy resources continue to grow, there is a global surge in the demand for technologies that reduce carbon emissions and enable the development of sustainable transportation solutions. The automotive industry, in particular, significantly impacts global carbon emissions, underscoring the increasing importance of eco-friendly electric vehicles (EVs) that produce no exhaust emissions [1; 2; 3; 4; 5]. Compared to traditional internal combustion engine vehicles, EVs effectively mitigate negative environmental impacts while achieving continuous advancements across various domains through technological innovation. These advancements include improvements in charging speed, extended driving range, enhanced battery lifespan, and the development of high-performance components to ensure stable operation [6; 7; 8; 9; 10]. Such technological progress has garnered positive responses from both consumers and industries, leading to a steady increase in research and investment aimed at developing electric vehicles that combine reliability with high performance [11; 12; 13; 14; 10].  
Electric vehicles (EVs) consist of key components such as electric motors, batteries, powertrains, and controllers. Among these, the electric motor converts electrical energy into rotational force, which is transmitted to the vehicle's wheels through the powertrain to enable movement. The drive shaft, often referred to as the constant velocity (CV) joint, plays a crucial role by maintaining consistent rotational speed between the input andoutput shafts regardless of the steering angle. The CV joint directly influences the dynamic characteristics of EVs, as it must handle the high torque output delivered from the electric motor, which often fluctuates rapidly. This torque demand is significantly higher than that of traditional internal combustion engine vehicles. In large EVs, such as SUVs and pickup trucks, the CV joint must exhibit exceptional durability to maintain stable performance under heavy loads and harsh driving conditions, allowing for high-speed and long-distance driving. Increased loads can lead to friction and heat generation within the drive shaft, potentially altering its operational characteristics. An insufficient understanding of thermal phenomena may result in thermal deformation, increased friction and wear, and ultimately reduced durability, which can critically impact the safety and performance of the vehicle. Consequently, research on the design of drive shafts capable of withstanding such high-load environments is essential. However, validating performance through extensive prototype development and experimental testing is not only time- and cost-intensive but also faces limitations in directly observing internal components or evaluating the effects of various conditions. To overcome these challenges, the finite element method (FEM) has emerged as a vital tool for research and development [15; 16; 17; 18; 19; 20]. The FEM enables the simulation of the complex structural behavior and physical phenomena occurring under diverse driving conditions in EVs. This approach allows for the analysis of structural and thermal stability during the design process, providing predictions of stress, deformation, and heat transfer. As a result, the FEM offers exceptional time and cost efficiency by enabling design optimization without the repeated need for prototype fabrication. Through precise numerical simulations, the FEM reduces dependency on physical testing, accelerating the development process while maintaining accuracy. This approach not only minimizes material and labor costs but also allows for the evaluation of multiple design scenarios under various conditions, ensuring optimal performance. By integrating the FEM into the design workflow, engineers can achieve faster iteration cycles and more reliable component development, making it a highly effective tool for modern engineering challenges.