Thermal stress occurs when materials expand or contract due to changes in temperature. This stress can lead to deformation, cracking, or failure in structures and components. For example, metals and concrete react differently to heat, which can create internal forces that compromise their integrity. In engineering, understanding thermal stress is crucial for designing safe and durable structures. Factors such as material properties, temperature changes, and environmental conditions must be considered. Proper management of thermal stress helps prevent issues in various applications, from bridges to machinery, ensuring they function effectively over time.