Dr Jem Rongong
School of Mechanical, Aerospace and Civil Engineering
Senior Lecturer
j.a.rongong@sheffield.ac.uk
+44 114 222 7845
+44 114 222 7845
Sir Frederick Mappin Building
Full contact details
Dr Jem Rongong
School of Mechanical, Aerospace and Civil Engineering
Sir Frederick Mappin Building
Mappin Street
Sheffield
S1 3JD
School of Mechanical, Aerospace and Civil Engineering
Sir Frederick Mappin Building
Mappin Street
Sheffield
S1 3JD
- Profile
-
Dr Jem Rongong has been involved in research into vibration damping technologies since the early 1990s. This has included a period as the Deputy Director of the Rolls-Royce Materials Damping UTC (200-2007). Jem has been a member of the academic staff in the Department since 2004.
Jem has been involved in research into vibration damping technologies since the early 1990s. He has projects with many different industries to reduce vibration in machinery through the effective use of passive damping methods.
His work in this area includes the experimental characterisation of new concepts, the development of efficient models and the design of improved equipment incorporating damping methods. One output from this research is an anti-vibration void filler that is now used on commercial airliners.
Jem has been a member of the academic staff in the Department since 2004 and teaches courses on vibration and design. He currently serves as Director of Learning and Teaching - Operations.
- Research interests
-
- Viscoelastic damping materials
- development, analysis and testing of polymers
- design and testing of syntactic foams and other multiphase systems
- Surface damping treatments
- free and constrained layer systems using organic and ceramic materials
- methods of application
- Friction-based systems
- design and analysis of particle dampers including the use of discrete element analysis
- granular polymeric materials as fillers
- metal mesh and other dry fibre systems
- Active & Adaptive Structures
- active constrained layer damping
- adaptive particle dampers
- shape memory actuated systems
- Design of damped components
- hollow turbomachinery blades
- numerical optimisation techniques including genetic algorithms and cellular automata
- composite structures
- Viscoelastic damping materials
- Publications
-
Journal articles
- Influence of particle sphericity on granular dampers operating in the bouncing bed motional phase. Journal of Sound and Vibration.
- Motional phase maps for estimating the effectiveness of granular dampers. Mechanical Systems and Signal Processing, 188.
- An evaluation of shoe tread parameters using FEM. Tribology International. View this article in WRRO
- Feasibility study on the use of tangled metal wire particles as the adjustable elements in tuned mass dampers. Journal of Sound and Vibration, 457, 1-4. View this article in WRRO
- Mechanical behaviour of tangled metal wire devices. Mechanical Systems and Signal Processing, 118, 13-29. View this article in WRRO
- Design of adjustable Tuned Mass Dampers using elastomeric O-rings. Journal of Sound and Vibration, 433, 334-348. View this article in WRRO
- An enhanced void-crack-based Rousselier damage model for ductile fracture with the XFEM. International Journal of Damage Mechanics. View this article in WRRO
- Extending the functionality of a symbolic computational dynamic solver by using a novel term-tracking method. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 232(19), 3439-3452. View this article in WRRO
- Damage detection in a laboratory wind turbine blade using techniques of ultrasonic NDT and SHM. Strain. View this article in WRRO
- Epoxidized natural rubber for vibro-acoustic isolation. Polymer Testing, 67, 92-98. View this article in WRRO
- Dynamic properties of unbonded, multi-strand beams subjected to flexural loading. Mechanical Systems and Signal Processing, 101, 168-181. View this article in WRRO
- The development of a new artificial model of a finger for assessing transmitted vibrations. Journal of the Mechanical Behavior of Biomedical Materials, 78, 20-27. View this article in WRRO
- Viscoelastic granular dampers under low-amplitude vibration. Journal of Vibration and Control, 24(4), 708-721. View this article in WRRO
- Measurements and predictions of the viscoelastic properties of a composite lamina and their sensitivity to temperature and frequency. Composites Science and Technology, 149, 207-219. View this article in WRRO
- Characterisation of creep behaviour using the power law model in copper alloy. Journal of Mechanical Engineering and Sciences, 11(1), 2503-2510. View this article in WRRO
- A new methodology for measuring the vibration transmission from handle to finger whilst gripping. International Journal of Industrial Ergonomics, 58, 55-61. View this article in WRRO
- Mechanical and Damping Properties of Resin Transfer Moulded Jute-Carbon Hybrid Composites. Composites Part B: Engineering, 105, 60-66. View this article in WRRO
- Effect of section thickness on fatigue performance of laser sintered nylon 12. Polymer Testing, 53, 204-210. View this article in WRRO
- On Crack Detection in Tuned and Mistuned Repeating Structures Using the Modal Assurance Criterion. Strain, 52(3), 175-185. View this article in WRRO
- A tangential microslip model for circularly and elliptically loaded structures. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 230(6), 900-909. View this article in WRRO
- Investigating the behavior of laser-sintered Nylon 12 parts subject to dynamic loading. Journal of Materials Research, 29(17), 1852-1858.
- Damping performance of metal swarfs in a horizontal hollow structure. Journal of Mechanical Science and Technology, 28(1), 9-13.
- System identification methods for metal rubber devices. Mechanical Systems and Signal Processing, 39(1-2), 207-226.
- Hysteretic properties of metal rubber particles. PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, 227(C4), 693-702.
- Temperature and strain rate dependence of syntactic foam under tensile and shear loads. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 227(1), 26-37.
- Crack characterisation by detection and classification of nonlinear behaviour using the Hilbert transform. PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, 226(C11), 2610-2626.
- An optimisation scheme based on the local interaction simulation approach and Lamb waves for elastic property estimation in multi-layered composites. Shock and Vibration, 19(5), 1027-1040.
- Polymeric particle dampers under steady-state vertical vibrations. Journal of Sound and Vibration.
- A finite element method for active vibration control of uncertain structures. Mechanical Systems and Signal Processing. View this article in WRRO
- The Behaviour of Naturally Debonded Composites Due to Bending Using a Meso-Level Model. Applied Composite Materials, 1-12.
- Control of Particle Damper Nonlinearity. AIAA J, 47(4), 953-960.
- On the energy leakage of discrete wavelet transform. MECH SYST SIGNAL PR, 23(2), 330-343. View this article in WRRO
- Strategies for using cellular automata to locate constrained layer damping on vibrating structures. J SOUND VIB, 319(1-2), 119-139. View this article in WRRO
- Energy dissipation prediction of particle dampers. J SOUND VIB, 319(1-2), 91-118. View this article in WRRO
- Damage detection in an aluminium plate using outlier analysis. FATIGUE FRACT ENG M, 31(8), 629-643.
- Damage localisation in a stiffened composite panel. STRAIN, 44(4), 298-307.
- Evolution of constrained layer damping using a cellular automaton algorithm. P I MECH ENG C-J MEC, 222(4), 585-597. View this article in WRRO
- Computer modelling of the dynamic response of viscoelastic vibroisolators. Journal Engineering Mechanics, 13, 19-30. View this article in WRRO
- The dynamic characterisation of disk geometry particle dampers. J SOUND VIB, 280(3-5), 849-861. View this article in WRRO
- Plasma deposition of constrained layer damping coatings. P I MECH ENG C-J MEC, 218(7), 669-680. View this article in WRRO
- The design of particle dampers for suppressing resonant vibrations.. Engineering Integrity, 2004, 25-30.
- Active constrained-layer damping: a state-of-the-art review. Proceedings of the I MECH E Part I Journal of Systems & Control Engineering, 217(6), 437-456.
- Active constrained-layer damping: a state-of-the-art review. P I MECH ENG I-J SYS, 217(I6), 437-456.
- Improving the modal strain energy method for damped structures using a dyadic matrix perturbation approach. P I MECH ENG C-J MEC, 216(12), 1207-1216.
- Advances in damping materials and technology. Smart Materials Bulletin, 2001, 10-13.
- Modelling of a hybrid constrained layer/piezoceramic approach to active damping. J VIB ACOUST, 119(1), 120-130.
- Suppression of ring vibration modes of high nodal diameter using constrained layer damping methods. SMART MATER STRUCT, 5(5), 672-684.
Chapters
- A Fuzzy Finite Element Method Programmed in MATLAB for the Analysis of Uncertain Control Systems of Structures, MATLAB - A Ubiquitous Tool for the Practical Engineer InTech
Conference proceedings papers
- The effect of particle surface roughness on granular energy dissipation performance. Proceedings of the 24th International Congress on Acoustics. Gyeongju, South Korea, 24 October 2022 - 28 October 2022.
- Construction of motional phase maps for granular dampers. Proceedings of the 51st International Congress and Exposition on Noise Control Engineering. Glasgow, United Kingdom, 21 August 2022 - 24 August 2022.
- The dissipative characteristics of oblate particles in granular dampers. EURODYN 2020: Proceedings of the XI International Conference on Structural Dynamics (pp 4851-4866). Athens, Greece, 23 November 2020 - 26 November 2020. View this article in WRRO
- Development of Rousselier model for creep damage problems with eXtended finite element method (XFEM) approach. Proceedings of the 6th European Conference on Computational Mechanics (Solids, Structures and Coupled Problems) (ECCM 6). Glasgow, 11 June 2018 - 15 June 2018. View this article in WRRO
- Development of modified-Rousselier model for creep damage problems in eXtended finite element method (XFEM) approach. CFRAC 2017. Nantes, France, 14 June 2017 - 16 June 2017.
- Dynamic properties of epoxidised natural rubber. 24th International Congress on Sound and Vibration, ICSV 2017
- Experimental investigation and modeling of dynamic performance of wave springs. Proceedings of 11th International Conference on Advances in Experimental Mechanics, 5 September 2016 - 7 September 2016. View this article in WRRO
- Mathematical and numerical evaluation of the damping behaviour for a multi-strand bar. Proceedings of 6th European Conference on Structural Control, 11 July 2016 - 13 July 2016. View this article in WRRO
- Damping of metallic wool with embedded rigid body motion amplifiers. Proceedings of 6th European Conference on Structural Control View this article in WRRO
- Modelling of an adjustable TMD incorporating an elastomeric O-ring. Proceedings of 17th International Conference on Experimental Mechanics View this article in WRRO
- Stiffness and damping of ordered frictional mesh material. ICSV 2016 - 23rd International Congress on Sound and Vibration: From Ancient to Modern Acoustics
- A microslip model for layered structures subjected to bending. Vibroengineering Procedia, Vol. 6 (pp 341-345)
- Stiffness and loss factor of unbonded, multi-strand beams under flexural deformation. Proceedings, 2015 International Conference on Engineering Vibration (pp 1518-1529). Ljubljana, Slovenia, 7 September 2015 - 10 September 2015. View this article in WRRO
- Dynamic mechanical propertis of woven carbon fibre reinforced thermoplastic composite materials. ICCM International Conferences on Composite Materials, Vol. 2015-July View this article in WRRO
- Nonlinear behaviour of tangled metal wire particle dampers. Proceedings of International Conference on Structural Engineering Dynamics 2015. Lagos, Portugal, 22 June 2015 - 24 June 2015. View this article in WRRO
- In situ Observation of NiTi Transformation Behaviour: A Micro–Macro Approach (pp 13-20) View this article in WRRO
- Fatigue Crack Detection in Vibrating Structures Using Outlier Detection Analysis. 2014 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM 2014) (pp 2298-2303)
- Dynamic mechanical properties of carbon nanotube-peek nanocomposite. 16th European Conference on Composite Materials, ECCM 2014
- Frequency and amplitude dependent behaviour of tangled metal wire dampers. Proceedings of ISMA 2014 - International Conference on Noise and Vibration Engineering and USD 2014 - International Conference on Uncertainty in Structural Dynamics (pp 559-572) View this article in WRRO
- Coulomb friction-induced damping estimation at the crack interface for cantilever-type specimen. 11th International Conference on Recent Advances in Structural Dynamics. Pisa, Italy, 1 July 2013 - 3 July 2013.
- Damage detection in a glass plate using outlier analysis. Key Engineering Materials, Vol. 569-570 (pp 847-853)
- Damping from metal swarf. International Conference on Structural Engineering Dynamics. Sesimbra, Portugal, 17 June 2013 - 19 June 2013.
- Investigation of dynamic mechanical properties of CNT reinforced thermoplastic polymer. Deformation and Fracture of Composites (DFC-12), 8 April 2013 - 11 April 2013.
- A single layer constitutive model for the dynamics and vibration damping of layered built-up structures using microslip and macroslip models. Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
- Damage identification in the mistuned bladed system utilizing the outlier analysis. Research and Applications in Structural Engineering, Mechanics and Computation - Proceedings of the 5th International Conference on Structural Engineering, Mechanics and Computation, SEMC 2013 (pp 2309-2314)
- Amplitude dependent damping from granular viscoelastics. MODERN PRACTICE IN STRESS AND VIBRATION ANALYSIS 2012 (MPSVA 2012), Vol. 382
- Damping technologies for demanding applications. International Conference on Structural Engineering Dynamics. Tavira, Portugal, 20 June 2011 - 22 June 2011.
- Identification and quantification of nonlinearities arising from a crack operating in flexural and torsion mode. 4th International Operational Modal Analysis Conference. Istanbul, Turkey, 9 May 2011 - 11 May 2011.
- Experimental investigation of MAC based crack detection technique for repeating structures. 4th International Operational Modal Analysis Conference,. Istanbul, Turkey, 9 May 2011 - 11 May 2011.
- Large Strain Behaviour of Syntactic Foam Damping Material. Deformation and Fracture of Composites (DFC-11) & Structural Integrity and Multi-scale Modelling (SI. Cambridge, UK, 13 April 2011 - 15 April 2011.
- The behavior of naturally debonded composites due to bending using a meso level model. DFC11 (Deformation and Fracture of Composites), Cambridge, DFC11 & SI5. Cambridge, UK, 13 April 2011 - 15 April 2011.
- Fatigue crack detection in vibrating structures using outlier detection analysis. Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 (pp 2298-2303)
- An Experimental and Numerical Investigation of Damage Detection in a Mistuned Bladed Disc. STRUCTURAL HEALTH MONITORING 2011: CONDITION-BASED MAINTENANCE AND INTELLIGENT STRUCTURES, VOL 1 (pp 1258-1265)
- Understanding the Effects of a Breathing Crack on the Dynamic Response of Cantilever-type Structures for Damage Detection. STRUCTURAL HEALTH MONITORING 2011: CONDITION-BASED MAINTENANCE AND INTELLIGENT STRUCTURES, VOL 1 (pp 848-855)
- Amplitude dependent crack characterization of growing fatigue cracks. Conference Proceedings of the Society for Experimental Mechanics Series, Vol. 5 (pp 83-92)
- The use of layered composites for passive vibration damping. Conference Proceedings of the Society for Experimental Mechanics Series, Vol. 3 (pp 289-298)
- Estudio de la influencia de la incertidumbre en el control active con materiales inteligentes. XVIII Congreso Nacional de Ingenieria Mecanica (pp 200). Ciudad Real, Spain, 3 November 2010 - 5 November 2010.
- Nonlinear static and dynamic properties of metal rubber dampers. ISMA 2010. Leuven, Belgium, 20 September 2010 - 22 September 2010.
- Linearized Material Properties of Nonlinear Interfacial Contact for Layered Composites. International Conference on Interfaces & Interphases in Multicomponent Materials Conference. Sheffield, UK, 1 September 2010 - 3 September 2010.
- Effective bulk properties of layered composites with 1D interfacial bonds. BSSM, New approaches for performance definition of composite materials and structures. Teddington, UK, 11 March 2010.
- Crack Detection in Mistuned Repeating Structures. PROCEEDINGS OF ISMA2010 - INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING INCLUDING USD2010 (pp 1083-1097)
- DETECTION OF DAMAGE IN REPEATING STRUCTURES. PROCEEDINGS OF THE ASME TURBO EXPO 2010, VOL 6, PTS A AND B (pp 1053-1061)
- Error bounds on master curves from least-squares estimation. Conference Proceedings of the Society for Experimental Mechanics Series
- Effects of enclosure geometry on particle damping performance. 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
- Damping of Flexible Structures with PEO Coating. International Conference of Fracture. Ottawa, Canada
- Control of particle damper nonlinearity. 49th AIAA/ASME Structures, Structural Dynamics & Materials Conference. Schaumberg, IL, 7 April 2008 - 10 April 2008.
- Damping properties of syntactic foams with nanoparticulate additives. Institution of Mechanical Engineers - 9th International Conference on Vibrations in Rotating Machinery, Vol. 2 (pp 745-759)
- Damage location in a stiffened composite panel using Lamb waves and neural networks. Conference Proceedings of the Society for Experimental Mechanics Series
- Prediction of the amplitude dependent behaviour of particle dampers. Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Vol. 4 (pp 4167-4182)
- Optimisation of passive and active constrained layer dampers for panel vibrations over broad frequency and temperature ranges. Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Vol. 5 (pp 4646-4655)
- Damage detection in an aluminium plate with an active constrained layer damping treatment. Damage Assessment of Structures VII, Vol. 347 (pp 205-212)
- Damage detection using prior wavelet decompositions. Damage Assessment of Structures VII, Vol. 347 (pp 145-150)
- Advanced design and modeling of nanoparticle-reinforced damping materials. Journal of Mechanical Engineering, Vol. 57(2) (pp 95-111)
- Advanced nanoparticle-reinforced composite materials in air-blast and vibration damping protection.. Polymer Nanocomposites, Vol. 31 (pp 31-41). San Antonio, Texas, USA, 12 March 2006 - 16 March 2006.
- Vibration damping properties of nanoparticle/tube/fibre-reinforced materials. Proceedings of the 6th International Conference European Society for Precision Engineering and Nanotechnology, EUSPEN 2006, Vol. 2 (pp 461-464)
- Macromodel characterisation and application of particle dampers to vibrating structures. Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Vol. 10 (pp 7327-7344)
- Damage detection in plates using transducers mounted on viscoelastic damping layers. Proceedings of the Third European Workshop Structural Health Monitoring 2006 (pp 300-307)
- Structural optimisation using a hybrid cellular automata (HCA) algorithm. Modern Practice in Stress and Vibration Analysis VI, Proceedings, Vol. 5-6 (pp 93-100)
- Designing materials for suppressing vibration. NOVEM 2005. Saint Raphaël, France, 18 April 2005 - 21 April 2005.
- Amplitude dependent behaviour of particle dampers. 10th Annual High Cycle Fatigue Conference (HCF 2005). New Orleans, 8 March 2005 - 11 March 2005.
- Characterisation of particle dampers using restoring force surface technique. STRUCTURAL DYNAMICS - EURODYN 2005, VOLS 1-3 (pp 1785-1790)
- Amplitude dependent behaviour in the application of particle dampers to vibrating structures. Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Vol. 10 (pp 6433-6441)
- Lightweight, polymeric cavity filler for damping hollow fan blade vibrations.. 9th Annual High Cycle Fatigue Conference (HCF 2004). Pinehurst, North Carolina, 16 March 2004 - 19 March 2004.
- The design of particle dampers for suppressing resonant vibrations. EIS Symposium on Nose, Vibration and Harshness. Coventry, UK, 6 November 2003.
- Passive damping materials for the future. Second Int. Workshop on Damping Technologies – Materials and Devices for the Next Decade. Stellenbosch, South Africa, 24 March 2003 - 26 March 2003.
- Improving the MSE method through a weighted damping IRS technique. PROCEEDINGS OF ISMA 2002: INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING, VOLS 1-5 (pp 403-409)
- Vibration damping using granular viscoelastic materials. PROCEEDINGS OF ISMA 2002: INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING, VOLS 1-5 (pp 431-440)
- Improving the MSE method for viscoelastic damped structures. SMART STRUCTURES AND MATERIALS 2002: DAMPING AND ISOLATION, Vol. 4697 (pp 25-34)
- Enhancement and evaluation of damping performance in layered CLD type coatings. SMART STRUCTURES AND MATERIALS 2001: DAMPING AND ISOLATION, Vol. 4331 (pp 198-208)
- Damage detection in an aircraft component model. PROCEEDINGS OF IMAC-XIX: A CONFERENCE ON STRUCTURAL DYNAMICS, VOLS 1 AND 2, Vol. 4359 (pp 1234-1241)
- Improving the MSE method for damped structures. NOISE AND VIBRATION ENGINEERING, VOLS 1 - 3, PROCEEDINGS (pp 317-324)
- Reducing vibration levels using 'Smart Joint' concepts. NOISE AND VIBRATION ENGINEERING, VOLS 1 - 3, PROCEEDINGS (pp 817-824)
- Identification of the influence of shock impact on the non-linear dynamic behaviour of double mass viscoelastic systems. 2nd International Conference on Identification in Engineering Systems (pp 276-287). Swansea
- Vibration suppression performance of piezoceramic and magnetostrictive materials in constrained layer damping. SMART STRUCTURES AND MATERIALS 1999: PASSIVE DAMPING AND ISOLATION, Vol. 3672 (pp 242-250)
- Damped joints for thin-plate structures. SMART STRUCTURES AND MATERIALS 1999: PASSIVE DAMPING AND ISOLATION, Vol. 3672 (pp 298-307)
- Detection of defects in a metal plate using Lamb waves and piezoelectric sensors. EXPERIMENTAL MECHANICS, VOLS 1 AND 2 (pp 767-772)
- Passive and active constrained layer damping of ring type structures. PASSIVE DAMPING AND ISOLATION - SMART STRUCTURES AND MATERIALS 1997, Vol. 3045 (pp 282-292)
- Smart Structures and Materials: Implications for Military Aircraft of New Generation. AGARD Lecture Series, Vol. 205 (pp 6-1-6-5)
- Modelling of active damping for the extensional vibration of a beam. IUTAM Symposium on Active Control (pp 255-262). Bath, 5 September 1994 - 8 September 1994.
- Retro-fit particle dampers for panels in space structures. Proceedings of the European Conference on Spacecraft Structures Materials and Environmental Testing. Toulouse, France, 28 March 2023 - 30 March 2023.
- Preliminary Results on Vibration Damping Properties of
Nanoscale-Reinforced Composite Materials. Dans European Nano Systems Worshop - ENS 2005, Paris : France
(2005)
- Non-linear Metamaterial Structures: Array of Particle Dampers. Non-linear Metamaterial Structures: Array of Particle Dampers (pp 4878-4884)
- EACS 2016 paper - Mathematical and numerical evaluation of the damping behaviour for a multi-strand bar
- EACS 2016 paper - Damping of metallic wool with embedded rigid body motion amplifiers
- Vibration transmissibility measurement of glove materials under different grip forces. Human Responses to Vibration. Southampton, UK, 9 September 2015 - 10 September 2015. View this article in WRRO
- MODELLING OF NONLINEAR DAMPERS UNDER LOW-AMPLITUDE VIBRATION. ACOUSTICS 2020, 5 October 2020 - 9 October 2020. View this article in WRRO
Posters
- Non linear Metamaterial Structures. Engineering Researchers Symposium.
Theses / Dissertations
- Vibrational energy dissipation mechanisms in granular dampers.
Datasets
- Experimental and simulation damping efficiency results of a granular damper, for various particle aspect ratios.
- Experimental data sets of a granular damper.
Presentations
- Nonlinear Metamaterial Structures. Italy.
- Influence of particle sphericity on granular dampers operating in the bouncing bed motional phase. Journal of Sound and Vibration.