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Published Articles

The Volume 17, No 2, June 2012

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Development of a Vibration-Based Crack Diagnostic Application Using the MANFIS Technique

Amiya Kumar Dash, Dayal R. Parhi


This paper analyses the effectiveness of a newly developed, multiple-crack diagnostic tool in dynamic structures using the multiple adaptive neuro-fuzzy inference system (MANFIS) technique. The effect of crack characteristics on the vibration responses have been investigated with different boundary conditions using finite element and numerical analysis. The first three relative natural frequencies, the difference of the first three average relative mode shapes , crack locations, and crack depths are used to train the fuzzy and neural controllers of the MANFIS system. The MANFIS controller is comprised of an input layer, a hidden layer and an output layer. The fuzzy segment uses the first three relative natural frequencies and the difference of the first three average relative mode shapes as the inputs. The hidden layer processes the outputs from the fuzzy controller. Finally, relative crack locations and relative crack depths are outputs from the developed MANFIS controller. It is observed that the predicted values of relative crack locations and relative crack depths from the formulated technique are well in agreement with the results from experimental analysis. The proposed methodology demonstrates its capability to be a suitable non destructive technique for fault identification in vibrating structures.

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Protection of the cultural heritage from underground Metro vibration & ground borne noise in Athens centre: The case of Kerameikos Archaeological Museum & Gazi Cultural centre.

Konstantinos Vogiatzis


This paper describes the assessment, implementation and verification of the necessary mitigation measures for the protection of the cultural heritage in the case of Kerameikos Museum & Gazi Cultural Centre in Athens cen-tre from underground Metro vibration & ground borne noise during the extension of line 3 from Monastiraki to Egaleo, The aim of this article is to present a state of the art assessment and evaluation of the behavior of the implemented mitigation measures in each sensitive archaeological finding in the area along the extension align-ment, through an extended measured program. In order to reach this objective, the relevant Athens Metro line section was divided into homogeneous sections: i.e. sections along which the tunnel and soil types, depth and distance from nearby buildings and presence or not of a switch were considered as constant. Particular emphasis was placed on sections in direct contact with the most important archaeological findings, such as the Museum and the relevant cultural uses. Data from the relevant prediction model were evaluated on the basis of a complete measurement campaign during Metro operation in the area. The implemented full floating slab solution, according to the measurement results during Athens Metro operation, has recorded levels of ground borne noise and vibration well within the severe criteria imposed for the Kerameikos area and Museum (as well as for the Gazi Cultural Centre & Radio station), both at soil surface locations and on marble statues and various artifacts on glass shelves in the Museum.

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A review of progress in soundscapes and an approach to soundscape planning

A.Lex Brown


The soundscape approach considers the acoustic environment as a resource, focussing on sounds people want, or prefer. Quiet is not a core requirement for such acoustic preference in the outdoor acoustic environment. Core requirements include that soundscape and landscape are congruent, and that wanted sounds in a place are dominant over, or not masked by, unwanted sounds. Acceptance, and further development, of the soundscape approach is facilitated by distinguishing it, both conceptually and in measurement and management approaches, from environmental noise management. Soundscape design, planning and management, based on soundscape concepts, augment environmental noise management approaches, expanding the scope of application of the tools of acoustic specialists.

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Acoustic response of multilayer with viscoelastic material



The development of materials both rigid and light with high damping effect and acoustic insulation is possible by using multilayer with viscoelastic layer. Rigidity of multilayer is provided by his elastic layers and damping is provided by viscoelastic layers. Prediction of the behavior of such systems in the conception phase is very important to determine the most important parameters in a multilayer panel in the aim to maximize insulation and to properly design this panel for several applications. For this, in this work we have developed a model based on transfer matrix method. It?s an analytic method to predict behavior of infinite layer subjected to a plane wave with an oblique incidence.

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Interference in Reading E-Paper under Whole- Body Vibration Exposure with Subject Posture

M.K. Bhiwapurkar, V.H. Saran, S.P. Harsha


There is increasing use of laptop computer in rail vehicles for performing various sedentary activities such as reading and typing. The vibration is a major factor influencing the reading performance during the journey. Therefore an experimental study was conducted to investigate the extent of interference perceived in reading e-paper in two seated postures (backrest support and leaning over the table) under random vibration. The study involved 30 healthy male subjects were excited with vibration in mono, dual and multi axis in 1?20 Hz at 0.4, 0.8 and 1.2 m/s2 amplitudes. The task consisted of reading the given paragraph of an e-paper under various vibration stimuli and was evaluated by time taken to complete the task and subjective evaluation of reading difficulty. The subjective evaluation showed that the reading difficulty increased with vibration stimuli, for both the subject postures. The subjects perceived higher difficulty and degradation in reading performance for vibration in dual and multi axes, which was comparable to that for lateral and vertical directions also. The perceived difficulty and impairment in reading performance was greater while reading with computer on lap for vibration in X- axis, while the effect was just the reverse for other axes.

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