Leonel F. Castañeda

Analysis of the procedure for suspension evaluation of civil armoured vehicles: reliability and safety driving criteria

The present study exposes an analysis of the suspension system technical state evaluation for civil vehicles that have been subject to armouring processes. Such evaluation is performed through a mechanised revision established by state regulation and is based on the method defined by EuSAMA. The development of this analysis focuses on establishing the existing relation between the ballistic resistance integrated to a vehicle and the dynamic effect exercised for the modification of its mass, according to two reliability/safety driving measurement criteria: (i) tyre-road adhesion index and (ii) tyre excitation phase angle. The study proposes new elements to the current procedure established to evaluate the suspension of civil armoured cars considering the two measurement criteria, which can be acquired by a standard commercial suspension tester machine.

Partial-profilogram reconstruction method to measure the geometric parameters of wheels in dynamic condition

ABSTRACT The present work poses a method for the measurement of geometric parameters of rail wheels in a dynamic condition, by reconstructing the profilogram from a portion of the wheel surface wear with artificial vision. The suggested procedure can work with a two-dimensional laser displacement transducer or by processing a sole image from a single camera with a structured light source. These two procedures require fewer devices and simpler implementation processes and allow the use of mathematical algorithms that demand less information processing, thus generating more accurate results. Railway operators may implement this method to perform predictive maintenance to their rolling stock at a fraction of the regular cost; thus achieving better precision, availability, maintenance performance and improving safety. Results were compared to those given by commercial equipment, showing similar precision but a better cost–benefit relation.

Journey Safety Assessment to Urban Aerial Ropeways Transport Systems Based on Continuous Inspection During Operation

This article proposes a continuous inspection method to assess the journey safety applied to aerial cable vehicles of mass transportation—a type of detachable gondola lift in terms of commercial operation in an urban area, specifically referring to the device coupling assembly on the track rope. The inspection method has been developed on the basis of a continual measurement process of the recorded strain conditions on a principal component of the coupling assembly. The selected component is commonly referred to as moving jaw. The proposed inspection procedure is structured based on the following set of consecutive stages: (i) characterization of the load states generated by the commercial operation of the system; (ii) definition of the sections of greater sensitivity to the strains caused by the load states, by means of finite elements; (iii) development of a measurement system; (iv) calibration of the measuring system with controlled tests; and (v) implementation and continuous records data in commercial operation.

Study of the state a Francis turbine

Abstract This paper presents a methodology to evaluate the technical state of a Francis turbine by shaft rotor dynamic simulation. There are several rotor dynamic criteria that define the technical state of a turbo-machine. To feed the shaft rotor dynamic model this delivers the required information to accomplish the technical assessment. The numerical rotor dynamic model uses as input, the field forces obtained by the fluid-solid interaction analysis undertaken over the blades of the runner. The rotor dynamic numerical simulations allow to determinate the record-in-time of the displacements of any point along the shaft. This information is relevant for diagnosis tasks, because it is possible to decompose it spectrally and to estimate the severity of the vibrations. Comparing the results of the numerical model against those obtained from machines that operates under normal conditions, it is possible to determinate the technical state of the turbo-machine. This allows studying the stability of the turbine working on several operation ranges. A Francis turbine is a very complex machine that involves many physical phenomena of different nature. In this way, the hydraulic input forces needed by the rotor dynamic model should not be assumed but calculated directly from the fluid interaction over the turbine structure.

Estimation of combustion engine technical state by multidimensional analysis using SVD method

The changes of vibration estimators as a result of engine maladjustment, waste, damage or failure are the main idea of vibrodiagnostic investigation. Diagnostic investigations that use vibration to determine the technical state of combustion engines are very difficult. A limited set of proposed methods could have use in diagnostics. This paper presents a validation of research results of the use of the singular value decomposition (SVD) method. The research object is a combustion engine with power 55 kW at 830 rpm, which is feasible to obtain signals generated by vibration, as well as investigate the influence of the engine in the variation of the vibroacoustic data. Using the SVD method is possible to decide which symptom in the observation matrix is the best to recognise the technical state of combustion engines.

A fractional Fourier transform-based method to detect impacts between the bogie and the car body of a railway vehicle: A data-driven approach

Structural railway transport elements are typically designed to work for at least 30 years without undergoing major maintenance. However, real-life operational conditions present behaviors different to the model predicted during the initial design phase, which affects the lifetime of the elements in question. This is the case of first-generation railway vehicles which operates in the city of Medellín, Colombia, as the bolster beam presented cracks after 12 years of operation, possibly due to undesired impacts between the bogie and the pivot of the bolster beam. Monitoring vibrational signals would give some sort of an insight into impact phenomena; however, herein lies the problem, as they are difficult to identify using only vibration signals, occurring during time events that take place in a speed-varying system. In this article, the authors present a technique that automatically detects impacts using multiple in-between time/frequency representations, ranking them according to their capacity to discriminate between impact events. Our results show that the best representation for this data was the Fractional Cepstrum Transform at order 0.5 (auROC = 0.961), which outperformed the best pure domain descriptor by least 4%.

Detection of structural damage and estimation of reliability using a multidimensional monitoring approach

Many structural elements are exposed to load conditions that are difficult to model during the design phase, such as environmental uncertainties, random impacts, and overloading, amongst others, thus increasing unprogrammed maintenance and reducing confidence in the reliability of the structure in question. One way to deal with this problem is to monitor the structural condition of the element. This approach requires supervising several signals coming from critical locations and then performing an accurate condition estimation of the element in question based on the data collected. This study implements a method to diagnose and evaluate the reliability of the bolster beam structure of the railway vehicle during a fatigue test. The results show that multidimensional monitoring not only diagnoses the element accurately but also results in correct estimation of reliability.

Maintenance policy optimisation for multi-component systems considering degradation of components and imperfect maintenance actions

Abstract This article proposes a stochastic optimisation model in order to reduce the long-term total maintenance cost of complex systems. The proposed work is based on the following approaches: (i) optimisation of a cost model for complex multi-component systems consisting of preventive and corrective maintenance using reliability analysis, which faces two different maintenance policies (periodic block-type and age-based) and (ii) a clustering method for maintenance actions to decrease the total maintenance cost of the complex system. This work evaluates each maintenance policy and measures the effects on imperfect maintenance actions. Finally, the proposed optimisation model is applied to a numerical example which focuses on passenger urban aerial ropeway transport systems, in which the current maintenance policy has been evaluated, considering the established by the international regulation of passenger aerial cable cars.

A study of the effect of the transition curve in the coupling elements between the carbody and the bogie

This work describes an analysis of the effect of the transition curves in the coupling elements between the carbody and the bogie, by means of recorded variables under commercial operation conditions of a railway vehicle. A set of field tests are developed and applied to the railway system as a basis to validate a numerical model. The dataset is obtained from a numerical model based on the multi-body systems theory using a transient method. The study focuses on the dynamic evaluation of the vehicle to determine the transversal dynamic effect generated by the circulation in the transition curve sections, especially in curves with short radius. The work includes a case study of a passenger railway, and it is used to identify aspects of the railway system that could be improved by the operators, such as inspection routines, rail track design and elements subjected to considerable loads.