Structural analysis of railways bolster-beam under commercial operation conditions: Over-traction and over-braking

The conditions for the operation of railway systems are closely related to the increase of the commercial demand; as a consequence, the performance of the structural elements of railways changes. The present paper focuses on a study of the structural behaviour of bolster-beams under commercial operation conditions of railway systems, specifically in the dynamic conditions generated in events of over-traction and over-braking on the vehicle running. The proposed work is constructed based on the following phases: (i) analysis of the kinematics of the vehicle; (ii) development of numerical models, a model based on the multibody theory, and a Finite Elements model; (iii) development of experimental field tests; and (iv) development of simulations for a detailed analysis of the structural behaviour for a study of the strain distribution in the main bolster-beam. This study is applied to a particular case of a railway system that provides commercial service to passengers

Technical condition assessment of masonry structural components using Frequency Response Function (FRF)

International standards indicate the need for adequate quality control in the production of masonry in the form of light bricks, double bricks, insulating bricks, breeze blocks, concrete blocks, etc. Quality control focuses on a set of criteria for establishing the technical condition of the bricks. The quality estimation methods, the technical condition assessment and the formulation of safety parameters for bricks are studied in this work. The paper proposes a non-intrusive method to test bricks in production plant conditions, focusing on quality control processes, as a method of conformity for units in a production line to identify the structural condition of the bricks, based on a Frequency Response Function (FRF). © 2016, International Masonry Society. All rights reserved

State of mechanical condition applied to industrial machines based on SVD method

A problem related to the operation of industrial machines has been the identification of the mechanical condition in exploitation, via dynamic performance variables which affect the nominal behavior of machine tasks. This paper proposes a set of algorithms focused on identifying of the mechanical condition industrial machines. Therefore, a tool to the maintenance based on the condition is developed; the methodology proposed is focused on the identification of the mechanical condition through recording dynamic variables by applying vibro-estimators techniques via Single Value Decomposition (SVD) method, and development of experimental tests on industrial machines. The work has been conducted on two sets of measurements from a real case study on two identical machines, one machine having nominal operation behavior, and the other machine having a dynamic problem. © 2018, Universidad de Tarapaca. All rights reserved

Quality identification methodology applied to wall-elements based on modal analysis

Purpose - The recommendation of structural standards, e.g. PN-B-03002, shows a need to control the production quality of wall-elements; the quality control demands suitable guidelines to fit the requirements of the current mass-production of the wall-elements, then, the structural standard recognizes the need of improving the methods to identify the real elements quality. The paper aims to discuss these issues. Design/methodology/approach - The proposed inspection methodology corresponds to assessment models that combine the numerical and symptomatic models to evaluate the critical levels of wall-elements, based on non-intrusive tests through the measurement of a set of signals, using the Experimental Modal Analysis (EMA)-based techniques. Findings - The presented work is developed with an approach that applies advanced calculating techniques used for the structural analysis in civil engineering focused on the technical state assessment. Originality/value - The paper proposes a diagnostic methodology that can be added to the current regulations and standards based on EMA techniques. © Emerald Group Publishing Limited

Joint optimisation of operation and maintenance policies in an urban ropeway transport systems context

Purpose The purpose of this paper is to propose a stochastic optimisation model for integrating service and maintenance policies in order to solve the queuing problem and the cost of maintenance activities for public transport services, with a particular focus on urban ropeway system. Design/methodology/approach The authors adopt the following approaches: a discrete-event model that uses a set of interrelated queues for the formulation of the service problem using a cost-based expression; and a maintenance model consisting of preventive and corrective maintenance actions, which considers two different maintenance policies (periodic block-type and age-based). Findings The work shows that neither periodic block-type maintenance nor an age-based maintenance is necessarily the best maintenance strategy over a long system lifecycle; the optimal strategy must consider both policies. Practical implications The maintenance policies are then evaluated for their impact on the service and operation of the transport system. The authors conclude by applying the proposed optimisation model using an example concerning ropeway systems. Originality/value This is the first study to simultaneously consider maintenance policy and operational policy in an urban aerial ropeway system, taking up the problem of queuing with particular attention to the unique requirements public transport services. </jats:sec

Evaluating damping elements for twostage suspension vehicles

The technical state of the damping elements for a vehicle having twostage suspension was evaluated by using numerical models based on the multibody system theory; a set of virtual tests used the eigenproblem mathematical method. A test was developed based on experimental modal analysis (EMA) applied to a physical system as the basis for validating the numerical models. The study focused on evaluating vehicle dynamics to determine the influence of the dampers' technical state in each suspension state

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. Copyright © 2013 Inderscience Enterprises Ltd

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. Copyright © 2013 Inderscience Enterprises Ltd

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

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. © 2018 Elsevier Lt