Sprag-slip

In Sects. 4.3.1 and 4.3.2, we study the classic Painleve s example and derive the conditions for the occurrence of the paradoxes. In Sect. 4.3.3, the concept of self-locking is introduced which is closely related to the kinematic constraint instability mechanism. In the rigid body systems, this phenomenon is sometimes known as jamming or wedging [97]. As we will see later on, the self-locking is an important aspect of the study of the dynamics of the lead screws. In Sect. 4.3.4, a simple model of a vibratory system is analyzed where the kinematic constraint mechanism leads to instability. In the study of disc brake systems, similar instability mechanism is sometimes referred to as sprag-slip vibration [7]. Some further references are given in Sect. 3.3.5. 

From (4.50), it is evident that if 0 tan (1/pj ), then N oo and further motion becomes impossible. In a more realistic setting where some flexibility is assumed, the motion continues by the deflection of the parts (see, e.g., Hoffmann and Gaul [98]). After sufficient deformation of the contacting bodies, slippage occurs which allows the bodies to assume their original configuration and the cycle continues. This situation is sometimes known as the sprag-slip limit cycle. 

Fig. 4.20 Simple model to demonstrate sprag-slip vibration...

Hoffinaim N, Gaul L (2004) A sufficient criterion for the onset of sprag-slip oscillations. Arch Appl Mech 73 650-660... 

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