Papers by Keyword: Bearings

Abstract: In this paper, a framework for conducting data-driven prognostics presence of a domainshift is introduced. Domain shift is brought about by factors such as changing operations which alterthe distribution of data thus degrading the performance of learned prognostic models. The use ofWeibull-based hazard functions of the kurtosis and shape factor time domain features are exploredand affirmed as not only being trendable and monotonic but robust across operating conditions; thus,desirable for prognosis. In the learning stage, the usual procedure is to use the designated training datawhich is full lifetime data. Unfortunately, a key characteristic of test data is that its truncated whichmay offer a serious impediment to the predicting model’s performance due to it being trained with fulllifetime data only. In this research, the learning data is extended by adding its truncated versions thussignificantly improving the model’s prediction accuracy for test data. In this work, it is demonstratedthat the proposed method results in over 95% accuracy of remaining useful life prediction for bearingsoperated in different operating conditions.

Abstract: In order to investigate the wear behavior of induction-heated 13Cr-2Ni-2Mo stainless steel, we performed the rolling contact fatigue (RCF) tests in water. We interrupted the RCF test at each 1.0×10⁵ cycles and measure the wear loss and observed the contact surface. After the RCF tests, we found the oxygen concentration area in the contact area.

Abstract: This study investigates the influence of the substitution of chromium (-0.8 wt.−%) by manganese (+1.3 wt.−%) in a standard quench and tempering steel and the predictability of property changes through simple simulations, only dependent on the chemical composition. The substitution of chromium by manganese leads to an increased hardness (+50 HV10) and a reduction of the critical cooling speed from 19 K s−1 for the reference alloys to 9 K s−1 for the new alloy and a nearly constant hardness of (600 HV10) after Jominy-test. The commercial software JMATPRO is used to simulate and predict key properties for the industrial production. It is shown that a successful simulation of phase transformation temperatures and the general directions of change can be predicted, but more complex properties like critical cooling rates or hardenability need more sophisticated methods.

Abstract: In this study, attempt has been made to investigate the effect of SiC particles on the friction and wear properties of Ni/SiC composites manufactured by electrodeposition, especially for the composites with high-temperature treatment.For this purpose, α-Al₂O₃ was coated on the surfaces of SiC particles by sol-gel technology to inhibit interfacial reaction of SiC and nickel at high temperature. Both of the Ni/α-Al₂O₃-coated SiC (Ni/CS_p) and Ni/uncoated SiC (Ni/UCS_p) composites were treated at 600 °C to study the resulting wear behaviour. The results indicated that with heat treatment at 600 °C, the Ni/CS_p composite had better tribological properties than the Ni/UCS_p composite. It was proved that the uncoated SiC particles have reacted completely with nickel leaving many defects, while the coated SiC particles still remained in the Ni/CS_p composite hardening the nickel matrix and supporting the counterpart, thus improving the wear resistance of Ni/CS_p composite with relatively low friction coefficient and wear mass loss compared to the Ni/UCS_p composite.

Abstract: A gear plays a crucial role in the performance of a gear box. The faults in a gear reduces the gear life and if problem arises in shaft it affects bearing. Gear box is finally affected due to these faults. Vibration signals carries information about condition of a gear box which are captured using piezoelectric accelerometer. In this paper, features are extracted and classified using K nearest neighbours (KNN) algorithms for both time and frequency domain. The effectiveness of KNN in classification of gear faults for both time and frequency domain is discussed and compared.

Abstract: Specification cutting tools durability made of cutting ceramic in machining process of steel 80MoCrV4016 is very important for economics of small and medium-sized enterprises, because cutting tool durability is factor that significantly affects the budget of these enterprises. This problematic is determined for small and medium-sized manufacturers of bearings, because steel 80MoCrV4016 is most commonly used for production of bearings. Durability of cutting tool defines lifetime of this cutting tool and it determines its suitability for select technological operation. Especially for cutting ceramic is necessary to define durability dependence on available set of cutting speeds and to determine lifetime of tools made of cutting ceramic. Technical science defines a lot of different factors, that they may be cause of shorter cutting tool lifetime. For increase cutting tool durability is necessary maximally possible elimination of these factors. Determination of cutting tool durability is very important, because provides comprehensive information how to determine appropriate technological conditions for selected cutting tool. In engineering is for determination of cutting tools durability used T-v_c dependence. The article describes process how to create durability dependence for cutting tools made of cutting ceramic by means of T-v_c dependence in machining process of steel 80MoCrV4016.

Abstract: Essential factors of each new discovery or piece of knowledge in science are predetermined, prepared and realized experiment. Every successfully realized experiment with obtained outputs and measurements indicates the gauge of asset that has been achieved by its execution. After analyzing of outputs final dependencies can be described that generalize whole experiment and allow entire process to be analytically identified. The production of bearings is very difficult process. Especially production of bearing rings is very complicated. Optimization of this process means significant savings for the company. Bearing rings are produced by turning. One of the most important parts of the turning process is cutting tool. On the base of cutting tools are determined many factors for example: quality, price, cutting speed, etc. All these factors of cutting tools are the only consequence of these cutting tools durability. Cutting tool durability determines its cutting properties and machinable ability. Specification of tool wear by means of calculation is very difficult. Durability of cutting tools is defined in standard ISO 3685. In standard ISO 3685 is defined T-v_c dependence for different cutting materials and standard included process evaluation of tool durability for cutting materials made of high speed steel, sintered carbide and cutting ceramic. The article describes evaluation of T-v_c dependence on the selected type of cutting materials and theirs comparison with measured values T-vc dependence that are defined in standard ISO 3685.

Abstract: In recent years, the lateral creeping happened from time to time to the curved concrete girder bridges when they are in service. This attracts much attention in the fields of the design, construction, maintenance of this kind of bridges since severe damage or collapse may happen to the whole structure when the lateral creeping displacement is large enough. In this paper, a comprehensive analysis is carried out on the lateral creeping of a curved two-span continuous concrete girder bridge which has been in service for 20 years to find out the possible reasons. A finite element model is appropriately developed for this example bridge using the commercial software Midas/Civil. Taking into account the dead loads, vehicle loads, thermal loads, etc., the safety and reliability of the original design of this bridge is proved first. And then the analysis is carried out for two possible reasons, bearing failure and expansion joints failure, respectively. The results show that the real reason of the bridge lateral creeping is that the expansion joints are stuck by the concrete blocks left when the expansion joints are replaced.

Abstract: Tribological surfaces of mechanical components encounter harsh conditions in terrestrial, marine and aerospace environments. Brinell denting, abrasive wear and fatigue often lead to life-limiting bearing and gear failures. Novel superelastic materials based upon Nickel-Titanium (NiTi) alloys are an emerging solution. NiTi alloys are intermetallic materials that possess characteristics of both metals and ceramics. NiTi alloys have intrinsically good aqueous corrosion resistance (they cannot rust), high hardness, relatively low elastic modulus, are chemically inert and readily lubricated. NiTi alloys also belong to the family of superelastics and, despite high hardness, are able to withstand large strains without suffering permanent plastic deformation. In this paper, the use of a hard, resilient NiTi alloy for corrosion-proof, shockproof bearing and gear applications is presented. Through a series of bearing and gear development projects, it is demonstrated that NiTi’s unique blend of material properties lead to significantly improved load capacity, reduced weight and intrinsic corrosion resistance not found in any other bearing materials. NiTi thus represents a new materials solution to demanding tribological applications.

Abstract: Nature works hard to destroy bearings, but their chances of survival can be improved by following a few simple guidelines. Extreme neglect in a bearing leads to overheating and possibly seizure or, at worst, an explosion. But even a failed bearing leaves clues as to what went wrong. After a little detective work, action can be taken to avoid a repeat performance.