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University Lecturer
01 July 2014 - 01 September 2021
University Lecturer
01 July 2012 - 01 July 2014
Others
01 July 2000 - 01 July 2012
- Senior Lecturer (Associate Professor) and Director of the undergraduate and postgraduate airworthiness programmes offered by the School of Engineering of the University of Limerick. - 20 years of professional & research experience in the fields of Aircraft Maintenance, Airworthiness Engineering, Aviation Safety, Technical/Logistics Support, Metal Plasticity and Metal Additive Manufacturing, both as an Aeronautical Engineer Officer in the Hellenic Air Force and a University Academic in Ireland and Australia. - Broad educational experience in teaching & supervising students at the University of Limerick, RMIT University and other Aviation & Engineering Institutions. - Chartered Engineer since 2012, registered with the UK Engineering Council, and a Fellow of the Royal Aeronautical Society.
Additive manufacturing (AM) technology has undergone an evolutionary process from fabricating test products and prototypes to fabricating end-user products—a major contributing factor to this is the continuing research and development in this area. AM offers the unique opportunity to fabricate complex structures with intricate geometry such as the lattice structures. These structures are made up of struts, unit cells, and nodes, and are being used not only in the aerospace industry, but also in the sports technology industry, owing to their superior mechanical properties and performance. This paper provides a comprehensive review of the mechanical properties and performance of both metallic and non-metallic lattice structures, focusing on compressive behaviour. In particular, optimisation techniques utilised to optimise their mechanical performance are examined, as well the primary factors influencing mechanical properties of lattices, and their failure mechanisms/modes. Important AM limitations regarding lattice structure fabrication are identified from this review, while the paucity of literature regarding material extruded metal-based lattice structures is discussed.
Solomon Obadimu; Kyriakos Kourousis. Compressive Behaviour of Additively Manufactured Lattice Structures: A Review. Aerospace 2021, 8, 207 .
AMA StyleSolomon Obadimu, Kyriakos Kourousis. Compressive Behaviour of Additively Manufactured Lattice Structures: A Review. Aerospace. 2021; 8 (8):207.
Chicago/Turabian StyleSolomon Obadimu; Kyriakos Kourousis. 2021. "Compressive Behaviour of Additively Manufactured Lattice Structures: A Review." Aerospace 8, no. 8: 207.
The purpose of this systematic review is to highlight the salient elements of learning from incidents in the aircraft maintenance and continuing airworthiness management area. This involved the review of more than 1,000 publications reflecting practice in different domains. The cache was eventually distilled to 18 publications of relevance to learning from incidents. The systematic review of the literature was not intended to be exhaustive, but it was deliberately bound by the parameters of predefined search terms. A robust analysis was performed on the 18 distilled publications with the use of the NVivo software. A critical and systematic examination of this body of literature further supported the development of the five codification themes. The analysis of the literature revealed the benefits of a just culture as an enabler of reporting and learning from incidents. Moreover, it identified limitations inherent in the current body of knowledge. The most evident being a paucity of literature relevant to the featured industry segment. Some impediments to learning from incidents are also highlighted. Central to this is the prevalence of lack of effective focus and practice on satisfactory causation of events. Currently, the efforts applied across many featured domains appear to be based upon ineffective legacy linear practices. However, emerging investigative philosophies that look beyond direct cause and effect contain opportunities for practitioners to consider causation through dawning axioms. This systematic review could be used in the European aviation regulatory activities associated with improving learning from incident in aircraft maintenance and continuing airworthiness management.
James Clare; Kyriakos I. Kourousis. Learning from Incidents in Aircraft Maintenance and Continuing Airworthiness Management: A Systematic Review. Journal of Advanced Transportation 2021, 2021, 1 -13.
AMA StyleJames Clare, Kyriakos I. Kourousis. Learning from Incidents in Aircraft Maintenance and Continuing Airworthiness Management: A Systematic Review. Journal of Advanced Transportation. 2021; 2021 ():1-13.
Chicago/Turabian StyleJames Clare; Kyriakos I. Kourousis. 2021. "Learning from Incidents in Aircraft Maintenance and Continuing Airworthiness Management: A Systematic Review." Journal of Advanced Transportation 2021, no. : 1-13.
Effective safety management has always been a key objective for the broader airworthiness sector. This Special Issue is focused on safety themes with implications on airworthiness management. It offers a diverse set of analyses on aircraft maintenance accidents [1–4], empirical and systematic investigations on important continuing airworthiness matters [5–7] and research studies on methodologies for risk and safety assessment in continuing and initial airworthiness [8–10]. Overall, this collection of papers is a valuable addition to the published literature, and I am confident that the readers of Aerospace will find that useful
Kyriakos I. Kourousis. Special Issue: Civil and Military Airworthiness: Recent Developments and Challenges (Volume II). Aerospace 2021, 8, 46 .
AMA StyleKyriakos I. Kourousis. Special Issue: Civil and Military Airworthiness: Recent Developments and Challenges (Volume II). Aerospace. 2021; 8 (2):46.
Chicago/Turabian StyleKyriakos I. Kourousis. 2021. "Special Issue: Civil and Military Airworthiness: Recent Developments and Challenges (Volume II)." Aerospace 8, no. 2: 46.
In this research paper fifteen mandatory occurrence reports are analysed. The purpose of this is to highlight the learning potential incidents such as these may possess for organisations involved in aircraft maintenance and continuing airworthiness management activities. The outputs from the mandatory occurrence reports are aligned in tabular form for ease of inclusion in human factors’ continuation training material. A new incident learning archetype is also introduced, which intends to represent how reported incidents can be managed and translated into lessons in support of preventing event recurrence. This ‘learning product’ centric model visually articulates activities such as capturing the reported information, establishing causation and the iterative nature of developing a learning product.
James Clare; Kyriakos Kourousis. Analysis of Continuing Airworthiness Occurrences under the Prism of a Learning Framework. Aerospace 2021, 8, 41 .
AMA StyleJames Clare, Kyriakos Kourousis. Analysis of Continuing Airworthiness Occurrences under the Prism of a Learning Framework. Aerospace. 2021; 8 (2):41.
Chicago/Turabian StyleJames Clare; Kyriakos Kourousis. 2021. "Analysis of Continuing Airworthiness Occurrences under the Prism of a Learning Framework." Aerospace 8, no. 2: 41.
Learning from incidents (LFI) is a useful approach when examining past events and developing measures to prevent ensuing recurrence. Although the reporting of incidents in the aircraft maintenance and continuing airworthiness domain is well appointed, it is often unclear how the maximum effect of safety data can be efficaciously applied in support of LFI in the area. From semi-structured interviews, with thirty-four participants, the gathered data were thematically analyzed with the support of NVivo software. This study establishes a relationship between an incident in its lifecycle and the learning process. The main aim of this work is to elucidate factors that enable LFI. The analysis of the data revealed, for example, the benefits of a just culture and the use of formal continuation training programs in this respect. Moreover, it identified limitations inherent in current processes such as poor event causation and poorly designed learning syllabi. Additionally, aspects such as a lack of regulatory requirements for competence in the areas of learning for managers and accountable persons currently exist. This thematic analysis could be used in support of organizations examining their own processes for learning from incidents. Additionally, it can support the development of terms of reference for a continuing airworthiness regulatory working group to examine, strengthen and better apply LFI in the aviation industry.
James Clare; Kyriakos Kourousis. Learning from Incidents: A Qualitative Study in the Continuing Airworthiness Sector. Aerospace 2021, 8, 27 .
AMA StyleJames Clare, Kyriakos Kourousis. Learning from Incidents: A Qualitative Study in the Continuing Airworthiness Sector. Aerospace. 2021; 8 (2):27.
Chicago/Turabian StyleJames Clare; Kyriakos Kourousis. 2021. "Learning from Incidents: A Qualitative Study in the Continuing Airworthiness Sector." Aerospace 8, no. 2: 27.
Maraging steel is an engineering alloy which has been widely employed in metal additive manufacturing. This paper examines manufacturing and post-processing factors affecting the properties of maraging steel fabricated via laser powder bed fusion (L-PBF). It covers the review of published research findings on how powder quality feedstock, processing parameters, laser scan strategy, build orientation and heat treatment can influence the microstructure, density and porosity, defects and residual stresses developed on L-PBF maraging steel, with a focus on the maraging steel 300 alloy. This review offers an evaluation of the resulting mechanical properties of the as-built and heat-treated maraging steel 300, with a focus on anisotropic characteristics. Possible directions for further research are also identified.
Barry Mooney; Kyriakos Kourousis. A Review of Factors Affecting the Mechanical Properties of Maraging Steel 300 Fabricated via Laser Powder Bed Fusion. Metals 2020, 10, 1273 .
AMA StyleBarry Mooney, Kyriakos Kourousis. A Review of Factors Affecting the Mechanical Properties of Maraging Steel 300 Fabricated via Laser Powder Bed Fusion. Metals. 2020; 10 (9):1273.
Chicago/Turabian StyleBarry Mooney; Kyriakos Kourousis. 2020. "A Review of Factors Affecting the Mechanical Properties of Maraging Steel 300 Fabricated via Laser Powder Bed Fusion." Metals 10, no. 9: 1273.
This article aims to present and discuss a set of technical matters affecting the maintenance and sustainment cost of military transport aircraft (airlifters). An overview of the military aviation technical support system is provided, in conjunction with a high level discussion on the life cycle cost. Four technical support pillars are defined as part of this analysis: supply, restoration and upgrade, engineering and regulatory compliance. A focused discussion on airlift sustainment factors, based on past experience, is used to identify technical considerations that can be used for the evaluation of new aircraft. A number of technical considerations which are key for cost purposes are identified and mapped against the defined technical support pillars, related to engineering and technical support and airworthiness management aspects. Important practical technical considerations are identified, discussed and critiqued under an independent lens. This article can stimulate discussion of the maintenance and sustainment costs of airlifters, both within military aviation operators and the defence industry community but also within the civil aircraft maintenance industry.
Kyriakos I. Kourousis. Airlift Maintenance and Sustainment: The Indirect Costs. Aerospace 2020, 7, 130 .
AMA StyleKyriakos I. Kourousis. Airlift Maintenance and Sustainment: The Indirect Costs. Aerospace. 2020; 7 (9):130.
Chicago/Turabian StyleKyriakos I. Kourousis. 2020. "Airlift Maintenance and Sustainment: The Indirect Costs." Aerospace 7, no. 9: 130.
The very diverse character of General Aviation (GA) within Australia poses challenges for its effective management of risk and safety in the sector. Improvements for human performance and perceptions of safety within the maintenance environment are among the areas which regulators have targeted for continuous improvement. This paper provides a timely empirical exploration of maintenance engineer perspectives around: (1) Changes in the role of the regulator/regulation that have impacted the sector and diminished safe operations; and (2) specific practical and operational challenges that the GA industry must deal with to sustain safe operations going forward. A thematic analysis of transcribed qualitative data revealed five key themes and identified a number of key issues from sector changes including a decline in training and education, drift in working practices, and wider power-distance gap. Issues with auditing and bureaucratization, negative safety climate, and underlying values and philosophies were also found. Practical and operational challenges going forward included an array of concerns associated with safety, the mismatch between GA and commercial aviation, workforce development and the financial burden in the sector. The results draw attention to the interconnectedness between various components of the GA system, and carry timely implications for regulation in the GA sector. Future research directions are discussed.
Anjum Naweed; Kyriakos I. Kourousis. Winging it: Key Issues and Perceptions around Regulation and Practice of Aircraft Maintenance in Australian General Aviation. Aerospace 2020, 7, 84 .
AMA StyleAnjum Naweed, Kyriakos I. Kourousis. Winging it: Key Issues and Perceptions around Regulation and Practice of Aircraft Maintenance in Australian General Aviation. Aerospace. 2020; 7 (6):84.
Chicago/Turabian StyleAnjum Naweed; Kyriakos I. Kourousis. 2020. "Winging it: Key Issues and Perceptions around Regulation and Practice of Aircraft Maintenance in Australian General Aviation." Aerospace 7, no. 6: 84.
Airworthiness, as a field, encompasses all those technical and non-technical activities required to design, certify, produce, maintain and operate safely an aircraft throughout its lifespan
Kyriakos I. Kourousis. Special Issue: Civil and Military Airworthiness: Recent Developments and Challenges. Aerospace 2020, 7, 37 .
AMA StyleKyriakos I. Kourousis. Special Issue: Civil and Military Airworthiness: Recent Developments and Challenges. Aerospace. 2020; 7 (4):37.
Chicago/Turabian StyleKyriakos I. Kourousis. 2020. "Special Issue: Civil and Military Airworthiness: Recent Developments and Challenges." Aerospace 7, no. 4: 37.
This short communication offers a preliminary view on ongoing research conducted on the as-built EOS maraging steel 300. The material’s cyclic elastoplastic characteristics under strain-controlled loading have been investigated experimentally. Specimens fabricated under two primary orientations, horizontally and vertically to the build plate, have been tested. The obtained stress–strain hysteresis loops exhibited symmetry, with the vertical specimen showing a higher plastic strain energy dissipation capability than the horizontal specimen. Modelling of the material’s elastoplastic behaviour was performed with a commonly used kinematic hardening rule, combined with both isotropic and anisotropic yield functions and elasticity moduli. The obtained simulations of the hysteresis loops, from the implementation of these two plasticity models, indicate the advantage of the anisotropic modelling approach over the isotropic approach. The anisotropic plasticity model describes in a more representative way the inherent elastic and plastic anisotropy of the as-built material. Further research is underway to explore the low cycle fatigue performance of this additively manufactured metal.
Barry Mooney; Dylan Agius; Kyriakos I. Kourousis. Cyclic Plasticity of the As-Built EOS Maraging Steel: Preliminary Experimental and Computational Results. Applied Sciences 2020, 10, 1232 .
AMA StyleBarry Mooney, Dylan Agius, Kyriakos I. Kourousis. Cyclic Plasticity of the As-Built EOS Maraging Steel: Preliminary Experimental and Computational Results. Applied Sciences. 2020; 10 (4):1232.
Chicago/Turabian StyleBarry Mooney; Dylan Agius; Kyriakos I. Kourousis. 2020. "Cyclic Plasticity of the As-Built EOS Maraging Steel: Preliminary Experimental and Computational Results." Applied Sciences 10, no. 4: 1232.
As part of the airworthiness requirements, an aircraft cannot be dispatched with an inoperative equipment or system unless this is allowed by the Minimum Equipment List (MEL) under any applicable conditions. Commonly, the MEL mirrors the Master MEL (MMEL), which is developed by the manufacturer and approved by the regulator. However, the increasing complexity of aircraft systems and the diversity of operational requirements, environmental conditions, fleet configuration, etc. necessitates a tailored approach to developing the MEL. While it is the responsibility of every aircraft operator to ensure the airworthiness of their aircraft, regulators are also required to publish guidelines to help operators develop their MELs. Currently, there is no approved standard to develop a MEL, and this poses a challenge to both aviation regulators and aircraft operators. This paper reviews current MEL literature, standards and processes as well as MEL related accidents/incidents to offer an overview of the present state of the MEL development and use and reinstate the need for a systematic approach. Furthermore, this paper exposes the paucity of MEL related literature and the ambiguity in MEL regulations. In addition, it was found that inadequate training and guidance on the development and use of MEL as well as lack of prior experience in airworthiness topics can lead to mismanagement and misapplication of the MEL. Considering the challenges outlined above, this study proposes the combination of system engineering and socio-technical system approaches for the development of a MEL.
Solomon O. Obadimu; Nektarios Karanikas; Kyriakos I. Kourousis. Development of the Minimum Equipment List: Current Practice and the Need for Standardisation. Aerospace 2020, 7, 7 .
AMA StyleSolomon O. Obadimu, Nektarios Karanikas, Kyriakos I. Kourousis. Development of the Minimum Equipment List: Current Practice and the Need for Standardisation. Aerospace. 2020; 7 (1):7.
Chicago/Turabian StyleSolomon O. Obadimu; Nektarios Karanikas; Kyriakos I. Kourousis. 2020. "Development of the Minimum Equipment List: Current Practice and the Need for Standardisation." Aerospace 7, no. 1: 7.
Kyriakos Kourousis. Constitutive modeling of additive manufactured Ti-6Al-4V cyclic elastoplastic behaviour. 2019, 1 .
AMA StyleKyriakos Kourousis. Constitutive modeling of additive manufactured Ti-6Al-4V cyclic elastoplastic behaviour. . 2019; ():1.
Chicago/Turabian StyleKyriakos Kourousis. 2019. "Constitutive modeling of additive manufactured Ti-6Al-4V cyclic elastoplastic behaviour." , no. : 1.
The tensile mechanical properties and anisotropy levels of identical test-coupons, fabricated from maraging steel 300 (MS300) using two alternative EOS EOSINT M280 Additive Manufacturing (AM) systems, have been examined. The mechanical performance variations resulting from process differences between the two suppliers and the part's build volume orientation (0 °, 45 °, 90 °) are investigated. Significant microstructural discrepancies, affecting mechanical performance, plasticity and anisotropy levels, have been observed in the as-built samples obtained from the two suppliers. A difference in the angle of the laser scan strategy, in conjunction with unfavourable powder feedstock characteristics, are understood to have had a profound influence on the plasticity and anisotropy divergences observed in the AM MS300 alloy. Plastic anisotropy levels can be largely reduced through application of aging heat-treatments, however, a degree of transverse strain anisotropy is likely to remain due to the AM alloy's fabrication history. Moreover, in this work both the anisotropic and elasticity tensors for this material are derived. These tensors can be used by researchers working on modelling and simulation of the MS300 mechanical properties.
Barry Mooney; Kyriakos I. Kourousis; Ramesh Raghavendra; Dylan Agius. Process phenomena influencing the tensile and anisotropic characteristics of additively manufactured maraging steel. Materials Science and Engineering: A 2018, 745, 115 -125.
AMA StyleBarry Mooney, Kyriakos I. Kourousis, Ramesh Raghavendra, Dylan Agius. Process phenomena influencing the tensile and anisotropic characteristics of additively manufactured maraging steel. Materials Science and Engineering: A. 2018; 745 ():115-125.
Chicago/Turabian StyleBarry Mooney; Kyriakos I. Kourousis; Ramesh Raghavendra; Dylan Agius. 2018. "Process phenomena influencing the tensile and anisotropic characteristics of additively manufactured maraging steel." Materials Science and Engineering: A 745, no. : 115-125.
This experimental study investigates the combined effect of the three primary Additive Manufacturing (AM) build orientations (0∘, 45∘, and 90∘) and an extensive array of heat treatment plans on the plastic anisotropy of maraging steel 300 (MS1) fabricated on the EOSINT M280 Direct Metal Laser Sintering (DMLS) system. The alloy's microstructure, hardness, tensile properties and plastic strain behaviour have been examined for various strengthening heat-treatment plans to assess the influence of the time and temperature combinations on plastic anisotropy and mechanical properties (e.g. strength, ductility). A comprehensive visual representation of the material's overall mechanical properties, for all three AM build orientations, against the various heat treatment plans is offered through time - temperature contour maps. Considerable plastic anisotropy has been confirmed in the as-built condition, which can be reduced by aging heat-treatment, as verified in this study. However, it has identified that a degree of transverse strain anisotropy is likely to remain due to the AM alloy's fabrication history, a finding that has not been previously reported in the literature. Moreover, the heat treatment plan (6h at 490∘C) recommended by the DMLS system manufacturer has been found not to be the optimal in terms of achieving high strength, hardness, ductility and low anisotropy for the MS1 material. With the use of the comprehensive experimental data collected and analysed in this study, and presented in the constructed contour maps, the alloy's heat treatment parameters (time, temperature) can be tailored to meet the desired strength/ductility/anisotropy design requirements, either for research or part production purposes.
Barry Mooney; Kyriakos I. Kourousis; Ramesh Raghavendra. Plastic anisotropy of additively manufactured maraging steel: Influence of the build orientation and heat treatments. Additive Manufacturing 2018, 25, 19 -31.
AMA StyleBarry Mooney, Kyriakos I. Kourousis, Ramesh Raghavendra. Plastic anisotropy of additively manufactured maraging steel: Influence of the build orientation and heat treatments. Additive Manufacturing. 2018; 25 ():19-31.
Chicago/Turabian StyleBarry Mooney; Kyriakos I. Kourousis; Ramesh Raghavendra. 2018. "Plastic anisotropy of additively manufactured maraging steel: Influence of the build orientation and heat treatments." Additive Manufacturing 25, no. : 19-31.
Purpose The purpose of this paper is to examine the mechanical behaviour of additively manufactured Ti-6Al-4V under cyclic loading. Using as-built selective laser melting (SLM) Ti-6Al-4V in engineering applications requires a detailed understanding of its elastoplastic behaviour. This preliminary study intends to create a better understanding on the cyclic plasticity phenomena exhibited by this material under symmetric and asymmetric strain-controlled cyclic loading. Design/methodology/approach This paper investigates experimentally the cyclic elastoplastic behaviour of as-built SLM Ti-6Al-4V under symmetric and asymmetric strain-controlled loading histories and compares it to that of wrought Ti-6Al-4V. Moreover, a plasticity model has been customised to simulate effectively the mechanical behaviour of the as-built SLM Ti-6Al-4V. This model is formulated to account for the SLM Ti-6Al-4V-specific characteristics, under the strain-controlled experiments. Findings The elastoplastic behaviour of the as-built SLM Ti-6Al-4V has been compared to that of the wrought material, enabling characterisation of the cyclic transient phenomena under symmetric and asymmetric strain-controlled loadings. The test results have identified a difference in the strain-controlled cyclic phenomena in the as-build SLM Ti-6Al-4V when compared to its wrought counterpart, because of a difference in their microstructure. The plasticity model offers accurate simulation of the observed experimental behaviour in the SLM material. Research limitations/implications Further investigation through a more extensive test campaign involving a wider set of strain-controlled loading cases, including multiaxial (biaxial) histories, is required for a more complete characterisation of the material performance. Originality/value The present investigation offers an advancement in the knowledge of cyclic transient effects exhibited by a typical α’ martensite SLM Ti-6Al-4V under symmetric and asymmetric strain-controlled tests. The research data and findings reported are among the very few reported so far in the literature.
Dylan Agius; Kyriakos I. Kourousis; Chris Wallbrink. Elastoplastic response of as-built SLM and wrought Ti-6Al-4V under symmetric and asymmetric strain-controlled cyclic loading. Rapid Prototyping Journal 2018, 24, 1409 -1420.
AMA StyleDylan Agius, Kyriakos I. Kourousis, Chris Wallbrink. Elastoplastic response of as-built SLM and wrought Ti-6Al-4V under symmetric and asymmetric strain-controlled cyclic loading. Rapid Prototyping Journal. 2018; 24 (9):1409-1420.
Chicago/Turabian StyleDylan Agius; Kyriakos I. Kourousis; Chris Wallbrink. 2018. "Elastoplastic response of as-built SLM and wrought Ti-6Al-4V under symmetric and asymmetric strain-controlled cyclic loading." Rapid Prototyping Journal 24, no. 9: 1409-1420.
The Airbus A320 family engine fan cowl doors (FCDs) safety issue is known to the industry for almost 18 years; however, it has not been addressed adequately by the aircraft manufacturer and the various operators and regulating authorities. The purpose of this paper is to examine in a systematic way the possible operational and safety implications of a new modification on the engine FCDs. An array of error-prone scenarios is presented and analysed under the prism of human factors in a non-exhaustive qualitative scenario analysis. All examined scenarios are considered more or less probable. A number of accident prevention solutions are proposed for each of the scenario examined, in view of the acceptance and implementation of this modification by operators. As these scenarios are neither exhaustive nor have been tested/validated in actual aircraft maintenance practice, the further analysis is necessary. A substantial follow-up survey should take place, which should include a wider array of scenarios. This would allow obtaining the necessary data for a quantitative (statistical) analysis. This case study identifies issues in relation to this modification, introduced by Airbus and the European Aviation Safety Agency (EASA), which may prove problematic from the point of view of safety effectiveness and disruption of operations. This case study examines a long-standing aviation safety issue and the implications of a solution proposed by the aircraft manufacturer and adopted by EASA. This can be useful in increasing the awareness around these issues and highlight the importance of a human-centric and scenario-based design of engineering modifications towards minimising error in aircraft technical operations.
Kyriakos I. Kourousis; Anna V. Chatzi; Ioannis K. Giannopoulos. The airbus A320 family fan cowl door safety modification: a human factors scenario analysis. Aircraft Engineering and Aerospace Technology 2018, 90, 967 -972.
AMA StyleKyriakos I. Kourousis, Anna V. Chatzi, Ioannis K. Giannopoulos. The airbus A320 family fan cowl door safety modification: a human factors scenario analysis. Aircraft Engineering and Aerospace Technology. 2018; 90 (6):967-972.
Chicago/Turabian StyleKyriakos I. Kourousis; Anna V. Chatzi; Ioannis K. Giannopoulos. 2018. "The airbus A320 family fan cowl door safety modification: a human factors scenario analysis." Aircraft Engineering and Aerospace Technology 90, no. 6: 967-972.
Three Ti-6Al-4V bolts from mid-life jet aircraft failed during service operation. Each of the failed bolts were installed on a landing gear component. Metallurgical failure analysis indicated that the fracture mechanism is low temperature creep, possibly resulting from a sustained tension load over a long time. Visual inspection revealed ductile fracture morphology with no macroscopic deformation or corrosion. For all bolts fracture occurred close to the root at the first pitches of the thread. Scanning Electron Microscope (SEM) analysis revealed dimple morphologies with micro-void coalescence. Energy Dispersive X-Ray (EDX) analysis did not reveal any material deficiency that would have precipitated failure.
Iordanis Spyroglou; Kyriakos Kourousis; Angelos Koutsomichalis. Investigation of In-service Creep Failures of Aircraft Ti-6Al-4V Bolts. MATEC Web of Conferences 2018, 188, 04008 .
AMA StyleIordanis Spyroglou, Kyriakos Kourousis, Angelos Koutsomichalis. Investigation of In-service Creep Failures of Aircraft Ti-6Al-4V Bolts. MATEC Web of Conferences. 2018; 188 ():04008.
Chicago/Turabian StyleIordanis Spyroglou; Kyriakos Kourousis; Angelos Koutsomichalis. 2018. "Investigation of In-service Creep Failures of Aircraft Ti-6Al-4V Bolts." MATEC Web of Conferences 188, no. : 04008.
The Multicomponent Armstrong-Frederick (AF) model with Multiplier (MAFM) has demonstrated high simulation accuracy for uniaxial and multiaxial loading conditions for a number of different materials. In this study the MAFM model is modified to improve the phenomenological modelling of aerospace aluminium alloys 7075-T6 and 7050-T7451 under uniaxial constant and variable amplitude loading. In order to recognise the experimentally observed strain amplitude dependency of mean stress relaxation rate, the coefficient of the linear kinematic backstress was modified from a constant to a strain amplitude dependent dynamic term. This modification improved the mean stress relaxation capability of the MAFM model. Additionally, the hysteresis loop evolution has been enhanced via further modification of the MAFM model by improving the monotonic stress-strain evolution of the initial loading branch of cyclic load cases by separating the kinematic backstress coefficients into two parts, the contributions from cyclic and monotonic micro-mechanisms. The monotonic coefficients were allowed to decay with continued cycling, which captured the monotonic to cyclic transition of stress-strain development. Finally, the experimentally observed reversibility of the monotonic stress-strain evolution has been also incorporated successfully through the introduction of a decaying strain range memory parameter, which improved the variable amplitude hysteresis loop evolution. Overall, the modified MAFM model has been successful in improving simulation accuracy of the cyclic elastoplastic response exhibited by both aluminium alloys examined.
Dylan Agius; Kyriakos I. Kourousis; Chris Wallbrink. A modification of the multicomponent Armstrong–Frederick model with multiplier for the enhanced simulation of aerospace aluminium elastoplasticity. International Journal of Mechanical Sciences 2018, 144, 118 -133.
AMA StyleDylan Agius, Kyriakos I. Kourousis, Chris Wallbrink. A modification of the multicomponent Armstrong–Frederick model with multiplier for the enhanced simulation of aerospace aluminium elastoplasticity. International Journal of Mechanical Sciences. 2018; 144 ():118-133.
Chicago/Turabian StyleDylan Agius; Kyriakos I. Kourousis; Chris Wallbrink. 2018. "A modification of the multicomponent Armstrong–Frederick model with multiplier for the enhanced simulation of aerospace aluminium elastoplasticity." International Journal of Mechanical Sciences 144, no. : 118-133.
Purpose This viewpoint aims to increase the awareness on the demand faced by the technical sector of the Indian and Chinese aviation industry and how this can be met by the adoption of the European Aviation Safety Agency (EASA) regulatory framework. Design/methodology/approach A brief overview of the challenges that the Indian and the Chinese aviation industry is facing is provided, in terms of meeting the demand for sustainable growth. A description of the structure of the EASA framework and its main characteristics is presented, along with a focussed discussion on the framework’s applicability to the Indian and the Chinese aviation maintenance and broader continuing airworthiness sector. Findings The EASA regulatory framework can offer a safe and business-effective solution for the Indian and the Chinese aviation industry, aligning with world’s best practice. Practical implications A discussion in adopting the EASA framework in India and China can be helpful in increasing awareness and assisting decision makers realise that this is a possible option. Originality/value This viewpoint can be useful in provoking discussion, by summarising the key issues and points surrounding aviation regulation standardisation in India and China, along the lines of the EASA framework. Moreover, some possible ways to increase awareness around EASA in India and China are discussed from the point of view of influencing tomorrow’s decision makers.
Kyriakos I. Kourousis; Anthony Comer. Indian and Chinese aviation industry: the EASA framework option. Aircraft Engineering and Aerospace Technology 2018, 90, 246 -250.
AMA StyleKyriakos I. Kourousis, Anthony Comer. Indian and Chinese aviation industry: the EASA framework option. Aircraft Engineering and Aerospace Technology. 2018; 90 (2):246-250.
Chicago/Turabian StyleKyriakos I. Kourousis; Anthony Comer. 2018. "Indian and Chinese aviation industry: the EASA framework option." Aircraft Engineering and Aerospace Technology 90, no. 2: 246-250.
Purpose This study presents the improvements of the multicomponent Armstrong–Frederick model with multiplier (MAFM) performance through a numerical optimisation methodology available in a commercial software. Moreover, this study explores the application of a multiobjective optimisation technique for the determination of the parameters of the constitutive models using uniaxial experimental data gathered from aluminium alloy 7075-T6 specimens. This approach aims to improve the overall accuracy of stress–strain response, for not only symmetric strain-controlled loading but also asymmetrically strain- and stress-controlled loading. Design/methodology/approach Experimental data from stress- and strain-controlled symmetric and asymmetric cyclic loadings have been used for this purpose. The analysis of the influence of the parameters on simulation accuracy has led to an adjustment scheme that can be used for focused optimisation of the MAFM model performance. The method was successfully used to provide a better understanding of the influence of each model parameter on the overall simulation accuracy. Findings The optimisation identified an important issue associated with competing ratcheting and mean stress relaxation objectives, highlighting the issues with arriving at a parameter set that can simulate ratcheting and mean stress relaxation for load cases not reaching at complete relaxation. Practical implications The study uses a strain-life fatigue application to demonstrate the importance of incorporating a technique such as the presented multiobjective optimisation method to arrive at robust parameters capable of accurately simulating a variety of transient cyclic phenomena. Originality/value The proposed methodology improves the accuracy of cyclic plasticity phenomena and strain-life fatigue simulations for engineering applications. This study is considered a valuable contribution for the engineering community, as it can act as starting point for further exploration of the benefits that can be obtained through material parameter optimisation methodologies for models of the MAFM class.
Dylan Agius; Mladenko Kajtaz; Kyriakos I. Kourousis; Chris Wallbrink; Weiping P Hu. Optimising the multiplicative AF model parameters for AA7075 cyclic plasticity and fatigue simulation. Aircraft Engineering and Aerospace Technology 2018, 90, 251 -260.
AMA StyleDylan Agius, Mladenko Kajtaz, Kyriakos I. Kourousis, Chris Wallbrink, Weiping P Hu. Optimising the multiplicative AF model parameters for AA7075 cyclic plasticity and fatigue simulation. Aircraft Engineering and Aerospace Technology. 2018; 90 (2):251-260.
Chicago/Turabian StyleDylan Agius; Mladenko Kajtaz; Kyriakos I. Kourousis; Chris Wallbrink; Weiping P Hu. 2018. "Optimising the multiplicative AF model parameters for AA7075 cyclic plasticity and fatigue simulation." Aircraft Engineering and Aerospace Technology 90, no. 2: 251-260.