Stick-slip transition in capillary flow of linear polyethylene: 3. Surface conditions

1997 ◽  
Vol 36 (2) ◽  
pp. 128-134 ◽  
Author(s):  
Shi-Qing Wang ◽  
Patrick A. Drda
Author(s):  
Torfinn Ottesen

Ocean currents may cause vortex induced vibrations (VIV) of deep-water umbilicals and cables. Since the VIV response may give significant contributions to the total fatigue damage it is important to know the structural damping for relevant curvature levels. A laboratory test has been performed on a 12.5 m long test specimen to determine the damping for a range of curvature levels that are in the vicinity of the stick-slip transition region. The energy input to maintain steady state oscillations with curvature amplitudes in the range 0.0002–0.001 m−1 was measured. The steady state energy input is consistent with damping ratios obtained using the free decay method. The structural damping depends on construction temperature and curvature and is less for typically low seawater temperature and low curvatures. The transition between the stick- and the slip regime is seen for typical seawater temperature.


2018 ◽  
Vol 113 (24) ◽  
pp. 241602 ◽  
Author(s):  
Alexander Breki ◽  
Michael Nosonovsky

Author(s):  
Abhishek Chatterjee ◽  
Alan Bowling

This work presents a new approach for resolving the unique invariant slip direction at Stick-Slip Transition during impact. The solution method presented in this work is applicable to both single-point and multi-point impact problems. The proposed method utilizes rigid body constraints to resolve the impact forces at all collision points in terms of a single independent impact forces parameter. This work also uses an energetic coefficient of restitution to terminate impact events, thereby yielding energetically consistent post-impact behavior.


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