The Use of the Vibroacoustic Method for Monitoring the Technical Condition of Aero Engines with Extended Time between Overhauls

2015 ◽  
Vol 220-221 ◽  
pp. 283-288
Author(s):  
Jarosław Spychała ◽  
Paweł Majewski ◽  
Mariusz Żokowski

The article presents some aspects of several years of work on the use of the vibroacoustic method (Non-Destructive Testing) for assessing a turboprop engine from a trainer aircraft. The functioning engine does not have an operating system for measuring vibration, and therefore the current levels of vibrations and its changes in trends are not known. In order to extend its service life, performing a number of works was required. On the basis of assessing the current state of the engine, opportunities for further exploitation were identified thus developing methodology for evaluating technical condition regarding the whole population. The paper shortly describes the object and equivalent tests on the engine. The article focuses on the methods prepared for extending life between overhauls required for turboprop engines and discusses the results received during their implementation.

2019 ◽  
Vol 91 ◽  
pp. 05020
Author(s):  
Vera A. Akristiniy

The article deals with the conservation of cultural heritage objects due to their potential widespread deterioration. The suggestion to solve this problem is to create an integrated system for complex monitoring of cultural heritage objects technical condition. The stages of creating a realtime monitoring system with the choice of non-destructive testing methods, the necessary instruments, and tools, the result of which is the formation of a decision-making mechanism for a particular object, are proposed. Conducting monitoring by means of modeling allows predicting the behavior of structures and the building as a whole, taking into account the implementation of restoration measures.


Author(s):  
S.O. Kozelskaya ◽  

The problem is considered related to increase of the operational safety of industrial facilities made of composite materials by means of an a priori assessment of the maximum service life. Two tasks are being solved: development of the new methods and means of non-destructive testing allowing to identify the defects that appear in the process of testing products with various loads and in the process of their operation; development of the new methods and means for assessing service life of the products based on the results of non-destructive testing. The first problem is being solved by the development of optical-thermographic non-destructive testing, including the technologies of ultrasonic thermotomography and electric force thermography, which determine the state of the object by dynamic temperature fields and optical control technology based on the fiber-optic sensors that measure the amount of material internal deformation under a force effect on the structure. Solution to the second problem is based on the use of neural network analysis (artificial neural networks) for assessment and prediction of the service life using the results of non-destructive testing with preliminary training of the neural network. An estimate was obtained by the experimental studies related to the error in determining the products service life, which is 12.6 %. The implementation of the proposed approach will allow to create the new technologies for predicting the service life of elements and structures made of composite materials using the results of non-destructive testing, which will provide an additional opportunity for developing practical recommendations on the confirmation or extension of the service life and improvement of safety for structures operation.


2020 ◽  
Author(s):  
Christina Plati ◽  
Andreas Loizos ◽  
Konstantinos Gkyrtis

<p>Performing structural assessment at any time of asphalt pavements service life is an inherent process within pavement condition assessment. Layers thicknesses are among the major contributors to the overall pavement response and performance. Knowledge of layer thicknesses is imperative for both new and in-service pavements, because thickness data is usually combined with other response indicators (i.e. pavement deflections) in order to perform pavement evaluation during pavements service life. As such, inaccuracies in thickness assessment might result in erroneous response analysis and life expectancy estimation with a detrimental financial impact during maintenance planning.</p><p>Traditionally, layer thicknesses were retrieved through coring or digging test pits. Because of the limitations of these methods (including location-specific information, destructive nature, need for traffic disruptions), the pavement engineering community has consistently drawn its attention to a broadened utilization of advanced Non-Destructive Testing (NDT) systems in order to non-invasively determine the pavement cross-section. The most indicative NDT tool for that purpose is the Ground Penetrating Radar (GPR), which is systematically used for layers thickness evaluation. Within the framework of pavement evaluation processes, GPR is quite often combined with the Falling Weight Deflectometer (FWD), which provides with pavement response indications in terms of surface deflections.</p><p>It is worthwhile mentioning that GPR requires high expertise in order to reliably analyze the collected data and until now, there is none uniquely recognizable and universally accepted signal processing scheme. Supplementary to experienced users and analysts, investments in time and human resources are also needed to make reliable interpretations. Such reasons may potentially discourage related stakeholders from systematic GPR use, especially in cases where there are budgets constraints for the procurement and transportation logistics of multiple expensive equipment.</p><p>In light of the above, related research is pursed in respect to the investigation of the ability of FWD surface deflections indexes to provide with reliable information on the Asphalt Concrete (AC) layer thicknesses. For this purpose, Long-Term Pavement Performance (LTPP) data is analyzed including FWD and GPR data as well as sample coring. A nonlinear regression based relationship is under development that preliminarily exhibits a satisfactory performance both during model fit and model accuracy evaluation. Based on the above framework, it is suggested that the NDT analysis with deflection indexes seems promising in terms of roughly producing AC thickness, thereby balancing constraints at network level.</p>


2014 ◽  
Vol 634 ◽  
pp. 479-484
Author(s):  
Ronaldo Alves Medeiros ◽  
Maryangela Geimba Lima

The need to insert the durability factor on dimensioning concrete structures has been stimulating the development of new models to predict the service life of those structures. Among those new models, the use of data from Non-Destructive Testing (NDT) is recommended. It is known that electrical resistivity is a parameter related with permeability and, in consequence, with the resistance of the concrete against the intrusion of aggressive agents. Electrical resistivity may be monitored with time by a NDT method, by a low cost and easy execution technique. However, some parameters of this essay need to be further discussed in the literature aiming to standardize this technique. Thus, this study had the goal to verify the influence of test specimen’s shape in measurements of electrical resistivity. In order to that, cylindrical and prismatic test specimens have been molded from a same type of concrete and electrical resistivity was monitored during a period of 120 days. Results show significant differences between the values obtained. Test specimens in cylindrical shape had the higher results. A good correlation between factors was found with R2 higher than 0.94.


Author(s):  
Vasyl Moshchenok ◽  
Lyidmila Kostina ◽  
Denis Pluzhnikov

One of the most common methods of non-destructive testing, hardness testing, is used to evaluate the properties of materials. This is due to the ease of measurement and testing of the finished part, which will be used in the future, high productivity of the method, the ability to assess other mechanical properties of the material: elasticity, creep, tensile strength. An important aspect in the study of the hardness using in the range the Berkovich and Vickers indenters, which are more consistent with non-destructive testing, while the methods of Brinell and Rockwell leave quite large deformations, in our opinion, which further promote the development of structural defects and reduce the service life, which are not acceptable in critical products. Due to the improvement of product manufacturability, more and more manufacturers are trying to minimize the size of the part, while increasing their performance by applying a reinforced layer, which, in turn, should seek to reduce the thickness with increased service life. It is also impossible to study the hardness of very small products in the micro range due to the large mismatch between the dimensions of the product under test and the test method. In our opinion, the study of hardness by the Berkovich method in comparison with the Vickers method is more expedient for use with the same physicochemical properties of the material because of a larger scatter of hardness values between the compared methods, although they should be almost the same, with a small difference. An important omission to a certain year was the dimensional effect. Goal. The aim of the study is to assess the nature of the change in hardness with increasing load on the indenter, using the functional dependence of the hardness on the depth of the indenter. For this purpose, it is necessary to establish such connection for an indenter of various geometry. In this regard, we consider it appropriate to check the validity of the Meyer equation, which relates the load to the size of the imprint, for different indenters and materials. Results. When the hardness is calculated according to the Martens scales, the Vickers and Berkovich indenters are applied to the function of the surface area of the working part of the tip. An important factor of the consistency of the results in the increase in hardness is the small effect. The reasons for this can be very negligible. The sizeable effect is significantly infused into the results of increasing hardness, changing from 2,5 to 3,0 folds.


2021 ◽  
Vol 257 ◽  
pp. 03071
Author(s):  
Jun Qiu ◽  
Zheng-qiu Huang ◽  
Li-xin Ren ◽  
Yao-ting Tong

Due to the long service life of a quayside container crane in an enterprise, there is slight corrosion on the surface of metal structure, which has potential safety hazard. In order to master the technical condition of the metal structure of the crane, the stress distribution and change information of the crane are obtained by dynamic and static stress testing and non-destructive testing. According to the analysis and test results, the safety assessment of the whole machine is completed and reasonable management suggestions are put forward.


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