1,721,052 research outputs found
UniVibe: A Novel User-Friendly Software for Automated Condition Monitoring and Diagnostics of Geared Transmission
No full textNowadays, huge emphasis is given to research on diagnostic tools in order to prevent and monitor the health status of gears and bearings. However, the link between advanced signal processing techniques and ease of use is still missing in commercial software tools. Actually, softwares that implement advanced signal processing techniques leak in ease user interaction and automated diagnostic procedures. Authors have developed a commercial software tool, called UniVibe, that attempts to fill the gap between high sensitivity in the diagnostics of faults in complex geared transmission and user-friendly interface. This work focuses on the description of the UniVibe core, highlighting its diagnostic capabilities on the basis of a real industrial case. Specifically, the automated procedure that shepherds the user to the successfully fault diagnosis of a complex geared transmission is pointed out
On the use of Vibration Signal Analysis for Industrial Quality Control: Part I
No full textVibration signals can be successfully captured and analyzed for quality control at the end of the production line. Various signal processing techniques and their applications are presented in this paper. These applications demonstrate the importance of selecting proper signal processing tools in order to extract the most reliable information from the signals. The presented applications regards tooth fault detection in helical gears and the detection of assembly faults in diesel engines by means of cold test technology
Dynamic Remaining Useful Life Estimation for a Shaft Bearings System
No full textInternational audienceCondition-based maintenance of rotating machines has become a subject of growing interest in 4.0 industry. Significant failures in industrial equipment are directly related to bearing degradation. Many techniques have been used successfully for diagnosing and forecasting bearing failures. However, accurately estimating the remaining useful life (RUL) of a bearing in operation remains a challenge. In industrial applications, the difficulty is usually related to the lack of available historical degradation signals. Therefore, in this chapter, a prognostic approach addressing the shortcomings of historical degradation data is presented. The latter bases on real-time acquired signals to build an adaptive predictive model for bearing degradation. Initially, diagnostic features associated to bearings are extracted from the available vibration signals. Then, an unsupervised DBSCAN classifier is used to detect degradation. As new degradation data become available, the extracted features are interactively ranked according to a defined selection criterion. The relevant feature is chosen as health indicator (HI). The degradation evolution and the RUL are estimated by an applied adaptive exponential degradation model, dynamically updated with each acquired sample. The applied strategy has been validated against vibration data acquired from a real wind turbine’s shaft bearings system
Stoneley Waves in Media with Microstructure
Get PDFThe role of microstructure in affecting propagation of antiplane Stoneley waves, that are waves localized at the discontinuity surface between two perfectly-bonded half-spaces, is considered. Microstructure is described within the linear theory of isotropic couple stress elastic materials with micro-inertia. The dispersion relation is a symmetric tri-term combination of the Rayleigh functions in the relevant half-space with a coupling term. In contrast to classical elasticity, where antiplane Stoneley waves are never supported and in-plane waves exist only inasmuch as shear velocities for the half-spaces are close enough, it is found that propagation is largely possible, although it occurs beyond a cuton frequency. For the latter, an explicit expression is given alongside dispersion curves. These results may adopted in next-generation non-destructive testing (NDT) appliances to account for the material microstructure
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effectiveness of Advanced Vibration Processing Techniques for Fault Detection in Heavy Duty Wheels
No full textThis paper assesses the application of different processing techniques on
acceleration signals extracted from faulty heavy duty wheels. Heavy duty wheels
are used in applications as automatic vehicles and are mainly composed of a
polyurethane tread glued to a cast iron hub. The adhesive application between tread
and hub is the most critical assembly phase, since it is completely made by an operator
and a contamination of the link area may happen. Furthermore the presence of
rust on the hub surface can contribute to worsen the adherence interface, reducing
the operating life. Several wheels with different types of faults have been manufactured
ad hoc with anomalies similar to the ones that can really be originated.
Synchronous average is calculated over the wheel rotation in order to highlight the
phenomena that have the wheel rotation as periodicity (e.g. the contact between defect
and test bench drum). Successively, cyclostationary theory is applied to extract
information from the frequency/order domain of the processed signals. Eventually,
well-suited indicators/coefficients are applied to the processed signals, objectifying
the anomaly presence and defining pass-fail reference values based on the nonstatistical
Tukey’s method
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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