Philip Cardiff
@ucd.ie
Associate Professor, School of Mechanical and Materials Engineering
University College Dublin
RESEARCH INTERESTS
finite volume methods; fluid-solid interaction; finite element methods; numerical methods; biomechanics; machine learning
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Parsa Esmati, Thomas Flint, Fatma Akyel, Simon Olschok, Uwe Reisgen, Philip Cardiff, Nicolas O. Larrosa, and Nicolò Grilli
Elsevier BV
Abdur Rahman Al Azad, Philip Cardiff, and David J. Browne
MDPI AG
A computational framework is developed to understand the transient behavior of isothermal and non-isothermal transformation between liquid and solid phases in a binary alloy using a phase-field method. The non-isothermal condition was achieved by applying a thermal gradient along the computational domain. The bulk solid and liquid phases were treated as regular solutions, along with introducing an order parameter (phase field) as a function of space and time to describe the interfacial region between the two phases. An antitrapping flux term was integrated into the present phase-field model to mitigate the amount of solute trapping, which is characterized by the non-equilibrium partitioning of the solute. The governing equations for the phase field and the solute composition were solved by the cell-centered finite volume method using the open-source computational tool OpenFOAM. Simulations were carried out for the evolution of equiaxed dendrites inside an undercooled melt of a binary alloy, considering the effect of various computational parameters such as interface thickness, strength of crystal anisotropy, stochastic noise amplitude, and initial orientation. The simulated results show that the solidification morphology is sensitive to the magnitude of anisotropy as well as the amplitude of noise. A strong influence of interface thickness on the growth morphology and solute redistribution during solidification was observed. Incorporating antitrapping flux resulted in the solute partitioning close to the equilibrium value. Simulations show that the grain shape is unaffected by changes to crystallographic orientation with respect to the Cartesian computational grid. Thermal gradients exerted discernible effects on the solute distribution and the dendritic growth pattern. Starting with multiple nucleation events the model predicted realistic polycrystalline solidification and as-solidified microstructure.
Ivan Batistić, Philip Cardiff, Alojz Ivanković, and Željko Tuković
Wiley
Yuxiang Zhang, Reamonn MacReamoinn, Philip Cardiff, and Jennifer Keenahan
MDPI AG
Aerodynamic performance is of critical importance to the design of long-span bridges. Computational fluid dynamics (CFD) modelling offers bridge designers an opportunity to investigate aerodynamic performance for long-span bridges during the design phase as well as during operation of the bridge. It offers distinct advantages when compared with the current standard practice of wind tunnel testing, which can have several limitations. The proposed revisions to the Eurocodes offer CFD as a methodology for wind analysis of bridges. Practicing engineers have long sought a computationally affordable, viable, and robust framework for industrial applications of using CFD to examine wind effects on long-span bridges. To address this gap in the literature and guidance, this paper explicitly presents a framework and demonstrates a workflow of analyzing wind effects on long-span bridges using open-source software, namely FreeCAD, OpenFOAM, and ParaView. Example cases are presented, and detailed configurations and general guidance are discussed during each step. A summary is provided of the validation of this methodology with field data collected from the structural health monitoring (SHM) systems of two long-span bridges.
I.L. Oliveira, P. Cardiff, C.E. Baccin, R.T. Tatit, and J.L. Gasche
Elsevier BV
Tatiana ștefanov, Bernard Ryan, Umair Javaid, Philip Cardiff, Alojz Ivanković, and Neal Murphy
Elsevier BV
Gowthaman Parivendhan, Philip Cardiff, Thomas Flint, Željko Tuković, Muhannad Obeidi, Dermot Brabazon, and Alojz Ivanković
Elsevier BV
Emad Tandis and Philip Cardiff
Elsevier BV
Thomas F. Flint, Joseph D. Robson, Gowthaman Parivendhan, and Philip Cardiff
Elsevier BV
Yuxiang Zhang, Conor Sweeney, Philip Cardiff, Fergal Cahill, and Jennifer Keenahan
Thomas Telford Ltd.
The safety and serviceability of long-span bridges can be significantly impacted by wind effects and therefore it is crucial to estimate them accurately during bridge design. This study develops full-scale three-dimensional computational fluid dynamics (CFD) simulation models to replicate wind conditions at the Rose Fitzgerald Kennedy Bridge in Ireland. The neglect of bridge geometries and the use of small scales in previous studies are significant limitations, and both the bridge geometry and surrounding terrain are included here at full scale. Input values for wind conditions are mapped from weather simulations that apply the weather research and forecasting model. Wind velocities at four different points calculated by CFD simulations are compared with corresponding data collected from structural health monitoring field measurements. The calculated time-averaged wind velocities at four different locations on the bridge are shown to have relative differences of less than 10% from the wind velocities measured by anemometers 90% of the time. The maximum relative difference among all comparisons was only 15%, shown to be partially due to the inclusion of the full bridge and terrain geometry.
I.L. Oliveira, P. Cardiff, C.E. Baccin, and J.L. Gasche
Elsevier BV
Seevani Bali, Željko Tuković, Philip Cardiff, Alojz Ivanković, and Vikram Pakrashi
Wiley
Thomas F. Flint, Gowthaman Parivendhan, Alojz Ivankovic, Michael C. Smith, and Philip Cardiff
Elsevier BV
I. Demirdžić and P. Cardiff
Informa UK Limited
Ke Wu, Željko Tukovic, Philip Cardiff, and Alojz Ivankovic
Begell House
Ivan Batistić, Philip Cardiff, and Željko Tuković
Elsevier BV
Yuxiang Zhang, Philip Cardiff, Fergal Cahill, and Jennifer Keenahan
MDPI AG
Despite its wide acceptance in various industries, CFD is considered a secondary option to wind tunnel tests in bridge engineering due to a lack of confidence. To increase confidence and to advance the quality of simulations in bridge aerodynamic studies, this study performed three-dimensional RANS simulations and DESs to assess the bridge deck aerodynamics of the Rose Fitzgerald Kennedy Bridge and demonstrated detailed procedures of the verification and validation of the applied CFD model. The CFD simulations were developed in OpenFOAM, the results of which are compared to prior wind tunnel test results, where general agreements were achieved though differences were also found and analyzed. The CFD model was also applied to study the effect of fascia beams and handrails on the bridge deck aerodynamics, which were neglected in most research to-date. These secondary structures were found to increase drag coefficients and reduce lift and moment coefficients by up to 32%, 94.3%, and 52.2%, respectively, which emphasized the necessity of including these structures in evaluations of the aerodynamic performance of bridges in service. Details of the verification and validation in this study illustrate that CFD simulations can determine close results compared to wind tunnel tests.
Pedro Veiga Rodrigues, Bruno Ramoa, Ana Vera Machado, Philip Cardiff, and João Miguel Nóbrega
MDPI AG
Toe caps are one of the most important components in safety footwear, but have a significant contribution to the weight of the shoe. Efforts have been made to replace steel toe caps by polymeric ones, since they are lighter, insulated and insensitive to magnetic fields. Nevertheless, polymeric solutions require larger volumes, which has a negative impact on the shoe’s aesthetics. Therefore, safety footwear manufacturers are pursuing the development of an easy, low-cost and reliable solution to optimize this component. In this work, a solid mechanics toolbox built in the open-source computational library, OpenFOAM®, was used to simulate two laboratory standard tests (15 kN compression and 200 J impact tests). To model the polymeric material behavior, a neo-Hookean hyper-elasto-plastic material law with J2 plastic criteria was employed. A commercially available plastic toe cap was characterized, and the collected data was used for assessment purposes. Close agreements, between experimental and simulated values, were achieved for both tests, with an approximate error of 5.4% and 6.8% for the displacement value in compression and impact test simulations, respectively. The results clearly demonstrate that the employed open-source finite volume computational models offer reliable results and can support the design of toe caps for the R&D footwear industry.
P. Cardiff and I. Demirdžić
Springer Science and Business Media LLC
Since early publications in the late 1980s and early 1990s, the finite volume method has been shown suitable for solid mechanics analyses. At present, there are several flavours of the method, including `cell-centre', `staggered', `vertex-centred', `periodic heterogenous microstructural', `Godunov-type', `matrix-free', `meshless', as well as others. This article gives an overview, historical perspective, comparison and critical analysis of the different approaches, including their relative strengths, weaknesses, similarities and dissimilarities, where a close comparison with the de facto standard for computational solid mechanics, the finite element method, is given. The article finishes with a look towards future research directions and steps required for finite volume solid mechanics to achieve widespread acceptance.
Pierre Aumjaud, David McAuliffe, Francisco J. Rodríguez Lera, and Philip Cardiff
Elsevier BV
Yuxiang Zhang, Philip Cardiff, and Jennifer Keenahan
MDPI AG
Engineers, architects, planners and designers must carefully consider the effects of wind in their work. Due to their slender and flexible nature, long-span bridges can often experience vibrations due to the wind, and so the careful analysis of wind effects is paramount. Traditionally, wind tunnel tests have been the preferred method of conducting bridge wind analysis. In recent times, owing to improved computational power, computational fluid dynamics simulations are coming to the fore as viable means of analysing wind effects on bridges. The focus of this paper is on long-span cable-supported bridges. Wind issues in long-span cable-supported bridges can include flutter, vortex-induced vibrations and rain–wind-induced vibrations. This paper presents a state-of-the-art review of research on the use of wind tunnel tests and computational fluid dynamics modelling of these wind issues on long-span bridges.
Pierre Aumjaud, David McAuliffe, Francisco Javier Rodríguez-Lera, and Philip Cardiff
Springer International Publishing
Reinforcement learning has shown great promise in robotics thanks to its ability to develop efficient robotic control procedures through self-training. In particular, reinforcement learning has been successfully applied to solving the reaching task with robotic arms. In this paper, we define a robust, reproducible and systematic experimental procedure to compare the performance of various model-free algorithms at solving this task. The policies are trained in simulation and are then transferred to a physical robotic manipulator. It is shown that augmenting the reward signal with the Hindsight Experience Replay exploration technique increases the average return of off-policy agents between 7 and 9 folds when the target position is initialised randomly at the beginning of each episode.
Luofeng Huang, Jukka Tuhkuri, Bojan Igrec, Minghao Li, Dimitris Stagonas, Alessandro Toffoli, Philip Cardiff, and Giles Thomas
Elsevier BV
Umair Javaid, Chen Ling, and Philip Cardiff
Elsevier BV
Laxmi Muralidharan, Philip Cardiff, Karen Fitzgerald, Robert Flavin, and Alojz Ivanković
SAGE Publications
A patient-specific numerical model of the ankle joint has been developed using open-source software with realistic material properties that mimics the physiological movement of the foot during the stance phase of the gait cycle. The patient-specific ankle geometry has been segmented as a castellated surface using 3DSlicer from the computed tomography image scans of a subject with no congenital or acquired pathology; subsequently, the bones are smoothed, and cartilage is included as a uniform thickness extruded layer. A high-resolution Cartesian mesh has been generated using cfMesh. The material properties are assigned in the model based on the CT image Hounsfield intensities and compared to a sandwich-based material model. Gait data of the same subject was obtained and used to relatively position the tibia, talus, and calcaneus bones in the model. The stance phase of the gait cycle is simulated using a cell-centred finite-volume method implemented in open-source software OpenFOAM. The predicted peak contact pressures occur in the range of 4.85–5.53 MPa with average pressures in the range of 1.56–1.95 MPa, and the contact area ranges between 429 and 707.8 mm2 for the entire stance phase with the mid-stance phase predicting the maximum contact area. These predictions are in agreement with results from the literature. The effect of arthritis on the contact characteristics of the ankle joint has also been examined. A concentrated increase in pressure was predicted that could be manifested as pain, thereby leading to reduced motion in the ankle. The model, with continued development, has the capability to understand the effect of joint degradation and furthermore, could help provide a tool to predict the efficiency of therapeutic surgical procedures as well as guide the development of next generation ankle prostheses. The work would be made available in the University College Dublin depository ( https://github.com/laxmimurali/anklejoint ) as well as research gate once the article has been published.