Yield criteria are guidelines used in engineering and materials science to determine when a material will deform or fail under stress. These criteria help predict how materials behave when subjected to forces, ensuring safety and reliability in structures and components. Common yield criteria include the von Mises and Tresca criteria, which assess the material's response to different types of loading. Understanding yield criteria is essential for designing safe structures, such as bridges and buildings, as they help engineers select appropriate materials and dimensions. By applying these criteria, engineers can ensure that materials will perform as expected under various conditions, preventing catastrophic failures.