Torsionsspänning

Torsionsspänning, or torsional stress, is a type of stress that occurs when an object is subjected to a twisting force, known as a torque. This force tends to rotate one part of the object with respect to another part around an axis. Torsionsspänning is particularly relevant in engineering, especially in the design of shafts and axles that transmit rotational power.

When a torque is applied to a solid circular cross-section, the stress is not uniform. The highest torsional stress occurs at the outer surface of the object, and it decreases linearly towards the center, where it is zero. For hollow circular cross-sections, the stress is still highest at the outer surface, but the reduction in stress towards the inner surface is less pronounced. For non-circular cross-sections, the distribution of torsional stress is more complex and can lead to stress concentrations, especially at corners or re-entrant angles.

The magnitude of torsionsspänning is directly proportional to the applied torque and inversely proportional to the polar moment of inertia of the cross-section. The polar moment of inertia is a geometric property that describes how the cross-sectional area is distributed around the axis of rotation. A larger polar moment of inertia means the object can withstand a greater torque before reaching its yield strength.

Understanding and calculating torsionsspänning is crucial for ensuring the structural integrity and safe operation of mechanical components. Failure due to excessive torsional stress can manifest as shearing, fracturing, or permanent deformation. Therefore, engineers must carefully consider material properties, geometry, and the expected torque loads during the design phase.