What is the definition of stiffness in engineering?

Stiffness in engineering is defined as the amount of force required to produce a unit of deformation in a material or structure. This definition captures the essence of stiffness as it quantitatively relates the applied force to the resulting displacement or deformation. Stiffness is an important parameter in structural engineering because it determines how much a given structure will deform under applied loads, which in turn affects the structural integrity and serviceability.

When considering the characteristics of stiffness, it can be mathematically expressed as the ratio of the applied force to the resulting displacement (deformation). This relationship is crucial in analyzing both structural components and entire systems, ensuring they can withstand imposed forces without excessive deflection or failure.

Defining it this way highlights that stiffness influences both the performance and safety of structures under various loading conditions, making it a fundamental concept in mechanical and civil engineering disciplines. Understanding how stiffness works allows engineers to design more efficient and safe structures by appropriately selecting materials and structural forms that best meet design criteria.