Bearing Capacity of Bored Pile with Large Length∕ Diameter Ratio

Author(s):  
Lan Kai ◽  
Yan Tai-ning ◽  
Yang Jian-lin
2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Wenshuo Ma ◽  
Jingjun Yu ◽  
Yiqing Yang ◽  
Yunfei Wang

Milling tools with a large length–diameter ratio are widely applied in machining structural features with deep depth. However, their high dynamic flexibility gives rise to chatter vibrations, which results in poor surface finish, reduced productivity, and even tool damage. With a passive tuned mass damper (TMD) embedded inside the arbor, a large length–diameter ratio milling tool with chatter-resistance ability was developed. By modeling the milling tool as a continuous beam, the tool-tip frequency response function (FRF) of the milling tool with TMD was derived using receptance coupling substructure analysis (RCSA), and the gyroscopic effect of the rotating tool was incorporated. The TMD parameters were optimized numerically with the consideration of mounting position based on the maximum cutting stability criterion, followed by the simulation of the effectiveness of the optimized and detuned TMD. With the tool-tip FRF obtained, the chatter stability of the milling process was predicted. Tap tests showed that the TMD was able to increase the minimum real part of the FRF by 79.3%. The stability lobe diagram (SLD) was predicted, and the minimum critical depth of cut in milling operations was enhanced from 0.10 to 0.46 mm.


Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Wenshuo Ma ◽  
Qiang Liu

The vibration absorber has been effective in vibration control. From the demand of manufacturing structural parts with a deep hole, the design of a turning cutting tool with large length–diameter ratio is presented. An analytical approach of acquiring frequency response of primary structure equipped with typical single-degree-of-freedom vibration absorbers is formulated, and background modes are incorporated with the purpose of achieving an accurate tuning of vibration absorber. Specifically, the three-element type is investigated as the damping element of the vibration absorber embedded in the cutting tool contributes to the stiffness, although it demonstrates medium performance of vibration suppression according to non-dimensional analysis. The experimentally tuned frequency response function of the turning cutting tool with three-element vibration absorber achieves 87.1% reduction on the amplitude of the target mode. Finally, several configurations of internal turning operations are carried out to validate the design of the vibration absorber.


2020 ◽  
Vol 554 (1) ◽  
pp. 204-211
Author(s):  
Zhongxia Duan ◽  
Haozhang Chen ◽  
Xiyue Tao ◽  
Hongxing Mi ◽  
Shuxun Lou ◽  
...  

2020 ◽  
Vol 15 ◽  
pp. 155892501990084 ◽  
Author(s):  
Tomasz Blachowicz ◽  
Andrea Ehrmann

One-dimensional materials, such as nanowires, nanotubes, or nanofibers, have attracted more and more attention recently due to their unique physical properties. Their large length-to-diameter ratio creates anisotropic material properties which could not be reached in bulk material. Especially one-dimensional magnetic structures are of high interest since the strong shape anisotropy reveals new magnetization reversal modes and possible applications. One possibility to create magnetic nanofibers in a relatively simple way is offered by electrospinning them from polymer solutions or melts with incorporated magnetic nanoparticles. This review gives an overview of most recent methods of electrospinning magnetic nanofibers, measuring their properties as well as possible applications from basic research to single-cell manipulation to microwave absorption.


2012 ◽  
Vol 446-449 ◽  
pp. 2449-2452
Author(s):  
Dong Guo Li ◽  
Gui Mei Shi

A viaduct of the Qinglai expressway fourth contract was artificial excavated piles. The construction technical work was regarded as an example. The technical comparison were done between the artificial excavated pile and the bored pile on the pile foundation bearing capacity and the retaining wall effect . The artificial excavated pile replacing the bored pile was feasible, and the construction technology and the key problems of the artificial excavated piles were confirmed. The references were provided to the similar projects.


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