Imperial College London

DrDanielAinalis

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Honorary Research Fellow
 
 
 
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Contact

 

d.ainalis Website

 
 
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Location

 

Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
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24 results found

Langshaw L, Ainalis D, Acha Izquierdo S, Shah N, Stettler Met al., 2019, Environmental and economic analysis of liquefied natural gas (LNG) for heavy goods vehicles in the UK: A Well-to-Wheel and total cost of ownership evaluation, Energy Policy, ISSN: 0301-4215

This paper evaluates the environmental and economic performance of liquefied natural gas (LNG) as a transition fuel to replace diesel in heavy goods vehicles (HGVs). A Well-to-Wheel (WTW) assessment based on real-world HGV drive cycles is performed to determine the life-cycle greenhouse gas (GHG) emissions associated with LNG relative to diesel. The analysis is complemented with a probabilistic approach to determine the total cost of ownership (TCO) across a range of scenarios. The methodologies are validated via a case study of vehicles operating in the UK, using data provided by a large food retailer. The spark-ignited LNG vehicles under study were observed to be 18% less energy efficient than their diesel counterparts, leading to a 7% increase in WTW GHG emissions. However, a reduction of up to 13% is feasible if LNG vehicles reach parity efficiency with diesel. Refuelling at publicly available stations enabled a 7% TCO saving in the nominal case, while development of private infrastructure incurred net costs. The findings of this study highlight that GHG emission reductions from LNG HGVs will only be realised if there are vehicle efficiency improvements, while the financial case for operators is positive only if a publicly accessible refuelling network is available.

Journal article

Kouroussis G, Zhu S-Y, Olivier B, Ainalis D, Zhai W-Met al., 2019, Urban railway ground vibrations induced by localized defects: using dynamic vibration absorbers as amitigation solution, JOURNAL OF ZHEJIANG UNIVERSITY-SCIENCE A, Vol: 20, Pages: 83-97, ISSN: 1673-565X

Journal article

Kouroussis G, Olivier B, Ainalis D, Zhu S, Zhai Wet al., 2019, Railway ground vibrations and designing dynamic vibration absorbers for urban rail transit

© Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019. All rights reserved. Dynamic vibration absorbers (DVAs) are widely accepted in vibration engineering as one of the most suitable ways to suppress undesirable low-damped resonance. In railway design, it is often placed on the track as a mitigation measure coupled to a floating slab. This paper presents the study of a tram vehicle equipped with DVAs with the aim to suppress the specific mode that affects the vehicle/track interaction and the surrounding ground wave generation. A complete vehicle/track/soil numerical model is developed and used to evaluate the dynamics of the whole system. Modal decomposition is applied to the vehicle/track model to obtain the optimal DVA parameter values for any location. Different DVA masses are analysed and different DVA locations are proposed. From the results, the vehicle bogie is revealed to be the best location and a compromise can be found for the DVA mass for reducing the ground vibration level of around 20%

Conference paper

Ainalis D, Rouillard V, Sek M, 2018, Estimation of road transport vehicle dynamic characteristics using random decrement analysis and on-the-road vibration data, INTERNATIONAL JOURNAL OF VEHICLE DESIGN, Vol: 76, Pages: 140-162, ISSN: 0143-3369

Journal article

Ainalis D, Achurra-Gonzalez P, Gaudin A, Garcia de la Cruz JM, Angeloudis P, Ochieng WY, Stettler MEJet al., Ultra-Capacitor based kinetic energy recovery system for heavy goods vheicles, 15th International Symposium on Heavy Vehicle Transport Technology

The Climate Change Act 2008 commits the UK to reduce the Greenhouse Gas emissions by 80% by 2050 relative to 1990 levels. While Heavy Goods Vehicles and buses contribute about 4% of the total Greenhouse Gas emissions in the UK, these emissions only decrease by 10% between 1990 and 2015. Urban areas are particularly susceptible to emissions and can have a significant impact upon the health of residents. For Heavy Goods Vehicles, braking losses are one of the most significant losses. A Kinetic Energy Recovery System can help reduce these emissions, and increase fuel efficiency by up to 30 %. This paper describes an InnovateUK funded project aimed at evaluating the technical and economic feasibility of a retrofitted Kinetic Energy Recovery System on Heavy Goods Vehicles through an operational trial, controlled emissions and fuel tests, and numerical modelling. A series of preliminary results using a numerical vehicle model is compared with operational data, along with simulations comparing the fuel efficiency of a Heavy Goods Vehicle with and without the KERS.

Conference paper

Ainalis D, Ducarne L, Kaufmann O, Tshibangu J-P, Verlinden O, Kouroussis Get al., 2018, Improved analysis of ground vibrations produced by man-made sources, SCIENCE OF THE TOTAL ENVIRONMENT, Vol: 616, Pages: 517-530, ISSN: 0048-9697

Journal article

Ducarne L, Ainalis D, Kouroussis G, 2018, Assessing the ground vibrations produced by a heavy vehicle traversing a traffic obstacle, SCIENCE OF THE TOTAL ENVIRONMENT, Vol: 612, Pages: 1568-1576, ISSN: 0048-9697

Journal article

Ainalis D, Olivier B, Ducarne L, Kouroussis Get al., 2018, Advanced road profile simulations and the dynamic tyre forces generated by heavy vehicles, Pages: 3801-3808

Copyright © (2018) by International Institute of Acoustics & Vibration. All rights reserved. Despite the growing popularity of alternative transport networks, road transport remains the dominant method for transporting goods and equipment. In order to remain competitive, the allowable mass limits of heavy vehicles are regularly increasing, enabling them to distribute more products per shipment. As heavy vehicles travel over the road surface, a complex dynamic interaction occurs, generating dynamic loads through the tyres and imparting these loads onto the pavements they traverse. Generally, the increased mass limits result in higher dynamic forces being exerted on pavements. These excessive dynamic loads can lead to rapid pavement deterioration, reducing the expected life of roads, and increasing the frequency of maintenance. In order to predict the dynamic tyre forces generated by these heavy vehicles, road elevation profiles (measured or syn-thesised) are used with vehicle dynamic models. The current approaches for simulating road profiles are, however, not adequate to excite the actual vehicle modes of vibration during transport; namely the heave, pitch, and roll motions. This paper presents a numerical investigation into the use of improved pavement elevation profiles and their influence on the dynamic tyre forces exerted by heavy vehicles. A complete four-wheeled heavy vehicle multibody model was developed using the in-house developed EasyDyn library, and simulated to travel over numerous road elevation profiles synthesised using MatLab. A comparison between the various profiles is presented, demonstrating their influence on the generated dynamic tyre forces.

Conference paper

Ducarne L, Ainalis D, Kaufmann O, Tshibangu JP, Verlinden O, Kouroussis Get al., 2018, Numerical modelling of blast-induced ground vibrations, Pages: 2379-2386

Copyright © (2018) by International Institute of Acoustics & Vibration.All rights reserved. In recent years, the mining industry has dealt with a significant amount of criticism regarding the side effects of production blasting. In practice, explosive material is placed into a series of boreholes in a rock mass, and then detonated to fragment the rock so that it can be disposed or transported for further processing. The detonation of an explosive charge is a rapid and high-energy reaction which imparts shock waves into the surrounding rock mass; however, not all energy is consumed in the fragmentation process. One of the most significant side effects of explosive blasting is the generated ground vibrations, which can travel a great distance from the site. With mining sites being located closer to urban areas due to urban growth, these generated ground vibrations can easily pose a problem for residents in the form of discomfort or structural damage. The focus of this paper is on the initial development of a numerical model to characterise the propagation of vibrations in these areas with two distinct aspects. The first part is focused on modelling the vibratory source. Since detonation and rock fragmentation are highly complex phenomena, the equivalent cavity theory is applied in order to maintain a single elastic ground model. The second part deals with the development of a ground model to simulate wave propagation and estimate the level of vibrations produced. The goal of this research is to develop numerical models which can be used by mining operators to predict the ground vibrations generated depending on factors such as the blast design, site configuration and geological parameters.

Conference paper

Kouroussis G, Ainalis D, Zhu S, Zhai Wet al., 2018, Mitigation measures for urban railway-induced ground vibrations using Dynamic Vibration Absorbers, Pages: 4124-4131

© 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. All rights reserved. Railway-induced ground vibration remains an important showstopper, especially in urban areas where significant levels of vibration are felt by residents. This paper presents a theoretical study of mitigation measures based on the use of Dynamic Vibration Absorbers (DVAs). Such devices can be tuned to a specific excitation frequency in order to reduce the forced response by absorbing the corresponding vibration resonance. The presented work focuses on the specific case of the T2000 tram circulating in Brussels, where large magnitudes of vibration are recorded during the passing over localized rail joints and turnouts. In order to design the DVAs, a numerical model is established, based on a recently developed two-step approach, which includes a coupled multibody model for the vehicle and a finite element/lumped mass model for the track. The model is completed with a 3D finite element model of the soil to simulate the ground wave propagation generated from the dynamic interaction between the vehicle and the track and can be used to evaluate the vibration level in the surrounding area. Tuned DVAs are also modelled, taking into account the design of each element. Finally, several comparisons are performed to quantify their efficiency and determine whether they are more effective in the vehicle or on the track.

Conference paper

Ainalis D, Ducarne L, Kaufmann O, Tshibangu JP, Verlinden O, Kouroussis Get al., 2017, Improved blast vibration analysis using the wavelet transform, 24th International Congress on Sound and Vibration 2017 (ICSV 24)

Explosive blasting is commonly used for the retrieval of usable materials or to excavate under-ground spaces. One of the most significant side effects produced by the explosive blasting process is the generation of vibrations which propagate through the ground and can travel great distances. Since it is becoming increasingly common for mining sites to be located near urban areas, the generated ground vibrations can induce not only cosmetic and structural damage, but also dis-comfort or injury to residents. Blasting engineers are constantly faced with an unavoidable com-promise; while the purpose of a blast is to fragment as much rock as possible, any increase in the size and energy of the blast can generate larger ground vibrations near the surrounding urban areas. The current monitoring and analysis of ground vibrations due to blasting are simplistic approaches which monitor only the dominant frequency and peak particle velocity of the meas-ured ground vibrations. This paper presents initial research into the use of the wavelet transform to provide an improved approach for investigating and analysing blast-induced ground vibrations. An overview of the two time-frequency methods; the short time Fourier transform, and wavelet transform, is included, along with an outline of the process for selecting a suitable wavelet for blast-induced vibrations. A series of blast-induced vibration records were obtained from a quarry in Wallonia, Belgium, and analysed using the two time-frequency methods for comparison.

Conference paper

Kouroussis G, Ducarne L, Ainalis D, 2017, Numerical modelling of the ground-borne vibrations generated by truck-road interaction, 24th International Congress on Sound and Vibration 2017 (ICSV 24)

Like railway-induced ground vibrations, ground-borne motions generated by the passing of heavy vehicles in urban areas are one of the fundamental problems in transport annoyance in the vicinity of buildings. In presence of local geometries like a speed bump or pavement defects, wheels interact with the road surface and cause dynamic motions in the vehicle that reacts with the road and generates high level vibrations that propagate in the soil through complex waves and impinge on the foundations of nearby structures. The scope of this study is twofold. The first part is dedicated to the prediction of vibration levels using a two-step approach. A multibody approach is used for the vehicle modelling, including the tyre/bump/road interaction. A finite element analysis is used for the next approach, calculating the ground wave propagation of a moving load, defined as the output of the first calculation. A decoupled simulation is possible due to the large stiffness of the road compared to the stiffness characteristics of the vehicle (tyre). A validation is performed using experimental data available in the literature. The second part focuses on a sensitivity analysis in order to identify the main parameters (bump geometry, speed,...) that affect the shape and level of peak particle velocity at various distances from the road. In light of the study, the prediction scheme offers an efficient way to design speed bumps and to understand the complex waves generated by a transient moving load propagating in an infinite medium.

Conference paper

Ainalis D, Rouillard V, Sek M, 2017, Practical Considerations for Estimating Road Vehicle Frequency Response Functions from Response Data, PACKAGING TECHNOLOGY AND SCIENCE, Vol: 30, Pages: 127-144, ISSN: 0894-3214

Journal article

Ainalis D, Kaufmann O, Tshibangu J-P, Verlinden O, Kouroussis Get al., 2017, Modelling the Source of Blasting for the Numerical Simulation of Blast-Induced Ground Vibrations: A Review, ROCK MECHANICS AND ROCK ENGINEERING, Vol: 50, Pages: 171-193, ISSN: 0723-2632

Journal article

Ducarne LC, Ainalis D, Kouroussis G, 2017, Ground vibration generated by the passing of a truck on a speed bump, Pages: 1972-1981

The growing levels of tra c in urban areas is becoming an increasingly important environmental issue in modern and developing countries. As a heavy vehicle travels over an uneven road surface a complex dynamic interaction occurs which induces dynamic loads into the ground. The generated ground vibrations propagate outwards and can lead to discomfort and / or damage to nearby bystanders and structures. The research presented in this paper is focused on the development of a two-step numerical model to estimate the ground vibrations generated from a heavy vehicle travelling over a speed bump (or geometric obstacle). The first step employs a multibody system to model the heavy vehicle and simulate the dynamic interaction between the vehicle and the geometric obstacle, while the second step makes use of the finite element method to simulate the propagation of ground vibrations. The multibody model is used to produce a time-history of the dynamic loads (i.e. contact forces) generated at the tyre-pavement interface, which is then input into the finite element ground model. Validation of the approach is undertaken through a comparison with well-established experimental results. The influence of various parameters, such as vehicle speed and geometric properties of the obstacle, were investigated through a sensitivity analysis. The resulting model is flexible and can be used to evaluate numerous vehicle-obstacle combinations on the ground vibrations generated.

Conference paper

Ainalis D, Kaufmann O, Tshibangu J-P, Verlinden O, Kouroussis Get al., 2016, ASSESSING BLAST SOURCE PRESSURE MODELLING APPROACHES FOR THE NUMERICAL SIMULATION OF GROUND VIBRATIONS, 23rd International Congress on Sound and Vibration (ICSV), Publisher: INT INST ACOUSTICS & VIBRATION, ISSN: 2329-3675

Conference paper

Ainalis D, Rouillard V, Sek M, 2016, Estimating the ride quality characteristics of vehicles with random decrement analysis of on-the-road vibration response data, VEHICLE SYSTEM DYNAMICS, Vol: 54, Pages: 765-783, ISSN: 0042-3114

Journal article

Ainalis D, Rouillard V, Sek M, 2015, On-the-road Measurements to Establish the Dynamic Characteristics of Transport Vehicles, PACKAGING TECHNOLOGY AND SCIENCE, Vol: 28, Pages: 657-671, ISSN: 0894-3214

Journal article

Ainalis D, Rouillard V, Sek M, 2015, Issues with Combining Road Elevation Spectral Models and Vehicle Vibration Response to Estimate Vehicle Dynamic Characteristics, PACKAGING TECHNOLOGY AND SCIENCE, Vol: 28, Pages: 253-270, ISSN: 0894-3214

Journal article

Ainalis DT, Rouillard V, Sek MA, 2014, Issues with the experimental characterisation of automotive shock absorbers for vehicle dynamic simulations, Pages: 323-331

Establishing the dynamic characteristics of wheeled vehicles is important for a number of applications including predicting the dynamic behaviour of vehicles and ride quality to transport vehicle occupants and products. Numerous approaches exist to estimate the dynamic characteristics of vehicles, however it is unclear which method establishes the true dynamic characteristics and is further complicated by vehicle suspension systems, which are typically nonlinear. As part of a broader research initiative, the authors are currently undertaking research into an evaluation of the various methods used to establish the dynamic characteristics of vehicles with a simple, idealised vehicle (physical quarter car). During the evaluation experiments, it was revealed that the factory-fitted shock absorber exhibited significantly nonlinear characteristics. For comparison, a second nominally-linear shock absorber was commissioned for use with the physical quarter car. To evaluate and characterise the two shock absorbers, they were mounted (one at a time) into a universal testing machine and subjected to various excitations, including constant-velocity actuations, various sinusoidal displacements and broadband random excitations. The original shock absorber was found to be extremely dependent on not only the velocity, but also the frequency, direction of motion and also the displacement amplitude. The custom-made linear shock absorber was found to exhibit far less variation in the damping and is notably not dependent on the direction of motion. The results presented highlight the difficulties encountered in characterising even a single component of a vehicle; the process is not straightforward and care must be exercised when selecting a suitable testing method.

Conference paper

Ainalis DT, Rouillard V, Sek MA, 2012, Evaluation of experimental techniques for establishing vehicle suspension characteristics, Pages: 788-799

This paper presents preliminary laboratory work that is part of a broader research initiative aimed at estimating the dynamic characteristics of wheeled vehicles using only in-service response data. In order to validate any proposed techniques, it is important that the true dynamic characteristics or Frequency Response Function (FRF) of the test vehicle(s) be known accurately. In order to isolate multiple-input and drive-train noise effects; a simple, single-wheeled, towable test vehicle representing a quarter car was commissioned. This paper focuses on the evaluation and comparison of spectral-based experimental methods representing averaged road elevation profiles to establish vehicle dynamic characteristics. The approaches examined make use of a vibration table to investigate the effect of various road spectra on obtaining consistent estimates of the dynamic characteristics of the test vehicle. The results presented in this paper show that, due to nonlinear behaviour of the suspension system, the system's dynamic characteristics are highly dependent on excitation type and level. The paper concludes that estimating the dynamic characteristics of a simple quarter-car vehicle is not straightforward and there are several challenges identified for the next phase of the research which is to estimate these dynamic characteristics using only in-service response data during normal operation.

Conference paper

Lamb M, Rouillard V, Ainalis D, 2011, An adaptive impulse response technique for evaluating the performance of structural elements, 21st Australasian Conference on the Mechanics of Structures and Materials (ACMSM), Publisher: CRC PRESS-TAYLOR & FRANCIS GROUP, Pages: 769-773

Conference paper

Lamb M, Rouillard V, Ainalis D, 2011, A multi-resolution time domain technique for monitoring fatigue progression in elements subjected to random loads, Australian Journal of Mechanical Engineering, Vol: 8, Pages: 103-112, ISSN: 1448-4846

Materials and structures subjected to random loading can deteriorate in a complex fashion. A technique for monitoring the manner in which this decay occurs can be useful, not in the least, for comparative analysis. One method for monitoring structural deterioration is to continually track variations in the system's modal parameters. Modal parameters are often extracted using the system's frequency response function, obtained using the Fourier transform. However, for continual parameter extraction, the Fourier transform requires that a compromise be made between the spectral accuracy of the estimates and how frequently they can be obtained. This compromise significantly limits the potential of Fourier transform based techniques as continuous structural integrity assessment tools. The technique presented herein applies the Hilbert transform to the system's instantaneous impulse response function, captured using the coefficients of an adaptive finite-impulse-response filter, in order to continually monitor shifts in the system's natural frequency. This approach allows for the properties of systems to be evaluated at regular intervals without compromising spectral uncertainty. Numerous damage scenarios were performed (using both physical and numerical systems) in order to test the sensitivity of the technique as well as its ability to converge with changes in system characteristics. © Institution of Engineers Australia, 2011.

Journal article

Lamb M, Rouillard V, Ainalis D, 2011, A practical approach to Fourier analysis for monitoring structural integrity, 21st Australasian Conference on the Mechanics of Structures and Materials (ACMSM), Publisher: CRC PRESS-TAYLOR & FRANCIS GROUP, Pages: 763-768

Conference paper

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