stick slip
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2022 ◽  
Vol 166 ◽  
pp. 108421
Beichao Shi ◽  
Fujun Wang ◽  
Zhichen Huo ◽  
Yanling Tian ◽  
Xiaolu Zhao ◽  

2022 ◽  
Vol 168 ◽  
pp. 108633
Xudong Zheng ◽  
Taiwei Yang ◽  
Zhang Chen ◽  
Xueqian Wang ◽  
Bin Liang ◽  

2022 ◽  
Vol 165 ◽  
pp. 108398
Qingbing Chang ◽  
Yingxiang Liu ◽  
Jie Deng ◽  
Shijing Zhang ◽  
Weishan Chen

2022 ◽  
Vol 164 ◽  
pp. 108226
Saeed Gheisari Hasnijeh ◽  
Hossein Karimpour ◽  
Mehrdad Poursina

2022 ◽  
Thomas Hudson ◽  
Sofia-Katerina Kufner ◽  
Alex Brisbourne ◽  
Michael Kendall ◽  
Andrew Smith ◽  

Abstract The slip of glaciers over the underlying bed is the dominant mechanism governing the migration of ice from land into the oceans, contributing to sea-level rise. Yet glacier slip remains poorly understood or constrained by observations. Here we observe both frictional shear-stress and slip at the bed of an ice stream, using 100,000 repetitive stick-slip icequakes from Rutford Ice Stream, Antarctica. Basal shear-stresses and slip-rates vary from 10^4 to 10^7 Pa and 0.2 to 1.5 m day^(-1), respectively. Friction and slip vary temporally over the order of hours and spatially over 10s of meters, caused by corresponding variations in ice-bed interface material and effective-normal-stress. Our findings also suggest that the bed is substantially more complex than currently assumed in ice stream models and that basal effective-normal-stresses may be significantly higher than previously thought. The observations also provide previously unresolved constraint of the basal boundary conditions of ice dynamics models. This is critical for constraining the primary contribution of ice mass loss in Antarctica, and hence the endeavour to reduce uncertainty in sea-level rise projections.

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 290
Tudor Deaconescu ◽  
Andrea Deaconescu

Reducing friction in the coaxial sealing systems of hydraulic cylinders is one of the solutions for increasing the energy efficiency of industrial actuations. This is a requirement, particularly in the case of small velocities that carry the risk of eigen-vibrations and/or stick-slip. The authors discuss the experimental research conducted on three coaxial sealing systems made from thermoplastic polymer and polyurethane type materials. The paper presents the equipment and method used for the experimental determination of static and kinematic friction coefficients and discusses the subsequent results obtained to test different working parameters. The experimentally determined friction coefficients yielded a range of materials recommended for coaxial seals such as to minimize the occurrence of jerky operation.

Guangda Qiao ◽  
Hengyu Li ◽  
Xiaohui Lu ◽  
Jianming Wen ◽  
Tinghai Cheng

Piezoelectric stick-slip actuators (PSSAs) are famous for ultimate working condition adaptability, simple structure, and positioning accuracy. To meet the demand of industrial application, lots of PSSAs designed with flexure hinge mechanisms (FHMs-PSSAs) have been developed to realize the requirements of translational motion, rotational motion, multi-degree-of-freedom (multi-DOF) motion. The output performance of the FHMs-PSSAs has been greatly improved, including load capacity, speed, and accuracy; moreover, some approaches to solve the problem of the backward motion are provided as well. In this work, the working principle of FHMs-PSSAs is introduced, and the excitation signals applicable to FHMs-PSSAs are summarized. Based on the current research and development status, the progress of structure design of FHMs-PSSAs is introduced in accordance with translatory FHMs-PSSAs, rotary FHMs-PSSAs, and multi-DOF FHMs-PSSAs. Additionally, the developed analysis methods and design schemes to improve the performance are introduced, including theoretical analysis methods, consistency scheme of forward and reverse performance, suppression scheme of the backward motion, and improvement scheme of positioning accuracy. The significance of this work can be regarded as a further supplement to the previous review articles on the PSSAs, which will provide a reference and guidance for the future development of FHMs-PSSAs.

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