Experimental Study on the Tribological Behavior of CaCO3/PEEK Composites under Water Lubrication

2010 ◽  
Vol 139-141 ◽  
pp. 98-101 ◽  
Author(s):  
You Xi Lin ◽  
Cheng Hui Gao ◽  
Yuan Li

The tribological properties of PEEK composites filled with CaCO3 whisker in various content of 0-30%(weight percent) were investigated.The composite specimens were prepared by compression molding. Tribological testing of composites in water lubrication against carbon steel ring was carried out on a MM200 block-on-ring apparatus.Data on neat PEEK were also included for comparison. The morphologies of wear traces were observed by SEM.It was observed that inclusion of CaCO3 whisker significantly improved the wear resistance and reduced the friction coefficient of PEEK composites under water lubricated condition. With an increase in CaCO3 whisker contents, the specific wear rate of composites decreased and showed minima for 20% CaCO3 content as 5.2% of that for PEEK. In terms of friction applications under water lubrication, the optimal content of CaCO3 whisker in PEEK composites should be recommended as 15% to 20%.The SEM observation of the wear traces indicated that the transfer film is not the main reason for the enhancement of wear resistance of the composites in water lubrication.CaCO3 whisker contributed to increase the load-carrying capacity and abate the scuffing and adhesion of PEEK composites, finally led to a significant improvement of the wear resistance.

Lubricants ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 67
Author(s):  
Sven Wirsching ◽  
Max Marian ◽  
Marcel Bartz ◽  
Thomas Stahl ◽  
Sandro Wartzack

In the context of targeted improvements in energy efficiency, secondary rolling bearing contacts are gaining relevance. As such, the elastohydrodynamically lubricated (EHL) roller face/rib contact of tapered roller bearings significantly affects power losses. Consequently, this contribution aimed at numerical optimization of the pairing’s macro-geometric parameters. The latter were sampled by a statistical design of experiments (DoE) and the tribological behavior was predicted by means of EHL contact simulations. For each of the geometric pairings considered, a database was generated. Key target variables such as pressure, lubricant gap and friction were approximated by a meta-model of optimal prognosis (MOP) and optimization was carried out using an evolutionary algorithm (EA). It was shown that the tribological behavior was mainly determined by the basic geometric pairing and the radii while eccentricity was of subordinate role. Furthermore, there was a trade-off between high load carrying capacity and low frictional losses. Thereby, spherical or toroidal geometries on the roller end face featuring a large radius paired with a tapered rib geometry were found to be advantageous in terms of low friction. For larger lubricant film heights and load carrying capacity, spherical or toroidal roller on toroidal rib geometries with medium radii were favorable.


2017 ◽  
Vol 8 (1) ◽  
pp. 63-78 ◽  
Author(s):  
Rhys Jones ◽  
Neil Matthews ◽  
Daren Peng ◽  
Nicholas Orchowski

Purpose The purpose of this paper is to describe the results of a combined numerical and experimental study into the ability of supersonic particle deposition (SPD) to restore the load carrying capacity of rib stiffened wing planks with simulated stress corrosion cracking (SCC). Design/methodology/approach In this context the experimental results reveal that SCC can result in a dramatic reduction in the load carrying capacity of the structure and catastrophic failure via cracking that tears the length of the structure through buckling. A combined numerical and experimental study then reveals how this reduction, in the load carrying capacity can be overcome by using SPD. Findings This paper is the first to show that SPD can be used to restore the load carrying capacity of rib stiffened structures with SCC. It also shows that SPD repairs can be designed to have only a minimal effect on the local stiffness and hence on the load path. However, care should be taken to ensure that the design is such that premature failure of the SPD does not occur. Originality/value This is the first paper to show that a thin layer of SPD deposited 7,075 aluminium alloy powder on either side of the SCC-simulated stiffener has the potential to restore the load carrying capability of a rib stiffened structure. As such it represents an important first step into establishing the potential for SPD to restore the buckling strength of rib stiffened wing panels containing SCC.


2013 ◽  
Vol 650 ◽  
pp. 582-587
Author(s):  
Kwang Hee Im ◽  
Ki Youl Kim ◽  
Ki Taek Shin ◽  
Han Hee Lee ◽  
To Kang ◽  
...  

Bush is one of machine and automobile parts like brake used in drums and hubs in particular. Such bush parts are used for bearings of heavy-duty, large cars requiring wear resistance and high load carrying capacity. High temperature diffusion bonding has been applied for holding the both materials of the bushing together, which are outer steel materials and inner composite-sintered bushings. Therefore, it is very important evaluate the bonding integrity in manufacturing process. A simulation has been performed in order to evaluate the maximum defect sizes. Also, ultrasonic C-scan tests were performed for finding the defect in the composite-sintered bushings with the size of inherent flaws.


2010 ◽  
Vol 163-167 ◽  
pp. 433-438
Author(s):  
Xian Lei Cao ◽  
Ji Ping Hao ◽  
Chun Lei Fan

To obtain a better understanding of the behavior and load-carrying capacity of Q460 high-strength single-angle compression members bolted by one leg, using static loading way to 48 angles carried out experimental study. The experiments show test specimens produce biaxial bending, most small slenderness ratio members are controlled by local buckling, and slender specimens are controlled by overall buckling. In addition to these factors in model experiment, influences of residual stresses on ultimate load-carrying capacity were analyzed by finite element numerical simulation analysis, the results show the residual stresses affect the ultimate load-carrying capacity of angles by about 5% or less. Comparison of the load-carrying capacity of experimental and theoretical results indicate the difference of experimental and finite element values ranges from -9.99% to +9.76%, American Design of Latticed Steel Transmission Structure (ASCE10-1997) and Chinese Code for Design of Steel Structures (GB50017-2003) underestimate separately the experimental load-carrying capacity by about 2.34%~33.93% and 1.18%~63.3%, and the agreement is somewhat good between experimental program and the finite element analysis. Based on model experiment and simulated experiment, the formula of stability coefficient of single-angle compression members was established. It provides basic data for spreading Q460 high-strength single-angles members attached by one leg.


2018 ◽  
Vol 8 (11) ◽  
pp. 2237 ◽  
Author(s):  
Wenwei Yang ◽  
Jiankang Lin ◽  
Ni-na Gao ◽  
Ruhao Yan

For truss structures, the question of whether to weld hidden welds or not has been controversial. In the actual construction process of truss structures, the members are usually spot welded in place on the assembly platform, and then welded as a whole, while the hidden welds of the truss are not welded, especially for small pipe diameter trusses. Furthermore, in this study, under hidden weld unwelded conditions, two kinds of reinforcing method (adding a half outer sleeve on each joint and filling concrete into the chord members) are adopted to achieve the purpose of strengthening the truss. Therefore, this paper presents an experimental study on the static behavior of four types of Warren tubular trusses made of CHS members. These four types are (1) T-HW: The truss with hidden welds welded; (2) T-HN: The truss with hidden welds unwelded; (3) TS-AS: The truss strengthened on the basis of T-HN by adding a half outer sleeve on each joint; (4) TS-FC: The truss strengthened on the basis of T-HN by filling concrete into the top and bottom chord members. The mechanical behavior, failure mode, bearing capacity, and load-displacement of all specimens were investigated. The surface plasticity of the bottom chord member, the weld fracture around tubular joints at the bottom chord member, and the bending deformation of the bottom chord member were observed in the tests. Compared with the T-HW specimen, the load carrying capacity of the T-HN specimen decreased by 18%. On the other hand, the T-HN specimen has better deformability than the T-HW specimen. The reinforcing method of adding a half outer sleeve on each joint and filling concrete into the chord members can effectively improve the load carrying capacity and stiffness of the truss, thus reducing the overall deformation of the truss, but the reinforcing method of filling concrete into the chord members is more efficient.


2007 ◽  
Vol 63 (1) ◽  
pp. 166-177 ◽  
Author(s):  
Shinichi TATSUKI ◽  
Takeshi TSUYOSHI ◽  
Tadayoshi ISHIBASHI ◽  
Yoshinori MATSUDA ◽  
Tsutomu IMAI

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