Kiertojännitys

Kiertojännitys, also known as torsional stress or torque, is a type of stress that occurs in a material when it is subjected to twisting forces. These forces create a shear stress within the material, causing its internal structure to deform. Imagine a rod being twisted; the outer layers of the rod experience greater shear stress than the inner layers. This stress is distributed across the cross-section of the object.

The magnitude of kiertojännitys depends on the applied torque and the geometry of the object. For a cylindrical shaft, the shear stress is highest at the outer surface and decreases linearly towards the center. The formula for maximum shear stress in a solid circular shaft is given by (Torque * Radius) / Polar Moment of Inertia. The polar moment of inertia is a geometric property that represents the object's resistance to torsion.

Kiertojännitys is a crucial consideration in mechanical engineering, particularly in the design of components like drive shafts, axles, and screws. Understanding and calculating kiertojännitys is essential to prevent material failure, such as fatigue or fracture, under rotational loads. Materials with high shear strength are preferred for applications involving significant torsional stress. The effects of kiertojännitys can be analyzed using principles of solid mechanics.