Transient friction loading, also known as TFL, is the mechanical stress induced on an object due to transient or vibrational frictional forces.
Examples
A classic example of TFL is the wooden block sliding over an unlevel, non-planar surface. Due to the transient response of the contact force, the resultant frictional force is noisy. The induced stress is concisely described as TFL.
Another example of TFL is the internal stresses on a hydraulic ram operating in a vibrational environment. Due to the oscilliatory nature of the acceleration experienced by the ram, in n-dimensions, the resulting frictional response is described as transient friction loading.
References
Transient friction loading Wikipedia(Text) CC BY-SA