Department of Machine and Industrial Product Design

1. Department of Machine and Industrial Product Design Contact person: Dr. Tibor Goda (e-mail: goda.tibor@gt3.bme.hu)

2. Initial guess for the film thickness(distance between mean surfaces at the given node) Geometrical sizes of the seal and the rodMaterial properties of the rubber seal (E,n)Sealed pressure (psealed)Rod speed (outstroke+instroke)Fluid viscosity at atmospheric pressure (m0)Pressure viscosity coefficient (a)Combined surface roughness of the rod andthe seal (s,R,h)Coefficient of friction at asperity contact (f) Length of the sealing zone (L)Number and coordinates of contact nodesStatic contact pressure at the contact nodes(psc)Influence coefficient matrix for the contactnodes (Iij)Static film thickness at the contact nodes (Hs) Contact analysis(Greenwood-Williamsoncontact model) Calculation of the flow factors Calculation of the truncated film thickness (hT) Discretized Reynolds equation (linear algebraic equations) non-linearity induced by pressure dependent viscosity Contact pressure due to asperity contact (pcontact) Fluid pressure (pfluid)Location of the full film and the cavitated regions Calculation of the total pressure (pt=pfluid+pcontact) Calculation of seal deformation induced by hydrodynamic and contact pressure Calculation of leakage and friction force Updated film thickness LUBRICATION AND FRICTION PREDICTION GM research topics relating to this area : 8, 10, 65 Competence in: 1. Modeling of adhesion 2. Boundary lubrication(shear strength of the boundary layer) 3. Numerical modelingof fluid and mixedfriction Department of Machine and Industrial Product Design

3. LUBRICATION AND FRICTION PREDICTION 4. Oil/grease lubricated sliding contact 5. Modeling of rheological behavior of lubricants Present research activity of the department in this field: EU FP6 research project „Knowledge-based Radical Innovation Surfacing for Tribology and Advanced Lubrication” (EU Project Reference NMP3-CT-2005-515837, www.kristal-project.org) References: [1] Kozma, M.: „Hydrodynamic and boundary lubrication of elastomer seals”, 19th International Conference on Fluid Sealing, Poitiers, France [2] Goda T. J.: "Numerical modelling of lubrication in reciprocating hydraulic rod seals„, Proceedings of sixth conference on mechanical engineering, ISBN 978-963-420-947-8, (2008)

4. RUBBER PHYSICS CONTACT MECHANICS, RUBBER FRICTION (SLIDING AND ROLLING), FE MODELLING GM research topics relating to this area : 31 Competence in: 1. Modeling of the non-linear, time- and temperature-dependent material behavior of rubber and rubber-like materials 2. Characterization of the asphalt’s surface topography (Power Spectral Analysis, surface roughness measurements, etc.) 3. Contact modeling of rubber/ rough counterpart sliding pairs Department of Machine and Industrial Product Design

5. RUBBER PHYSICS CONTACT MECHANICS, RUBBER FRICTION (SLIDING AND ROLLING), FE MODELLING 4. FE modeling of hysteresis induced rolling and slidingresistance 5. FE modeling of hysteresis induced and friction related heat generation (thermo-mechanical coupled analysis) Present research activity of the department in this field: EU FP6 research project „Knowledge-based Radical Innovation Surfacing for Tribology and Advanced Lubrication” (EU Project Reference NMP3-CT-2005-515837, www.kristal-project.org) References: [1] Goda, T.; Pálfi, L.; Váradi, K.; Garbayo, E.; Bielsa, J.M.: “FE prediction of the hysteretic component of rubber friction: importance of the Maxwell-parameters”, Fall Rubber Colloquium, (2008), pp. 128 [2] Felhős, D.; Xu, D.; Schlarb, A.K.; Váradi, K.; Goda, T.:”Viscoelastic characterization of an EPDM rubber and finite element simulation of its dry rolling friction”, EXPRESS POLYMER LETTERS, Vol. 2, No.3, (2008) pp.157-164 Department of Machine and Industrial Product Design

6. FE THERMAL MODELLING GM research topics relating to this area : 67 Competence in: 1. Transient and steady-state FE thermal modeling (heat partition, thermal contact resistance, contact conductive heat flux, etc.) 2. Stick-slip related thermal problems 3. Coupled thermo-mechanical analysis Department of Machine and Industrial Product Design

7. FE THERMAL MODELLING 4. Moving and distributed heat source models Present research activity of the department in this field: Hungarian National Scientific Research Foundation project: „Friction behaviour and failure mechanisms of polymer, elastomer, ceramic and composite structural components”, OTKA (NI 62729) References [1] Lestyán, Z.; Váradi, K.; Albers, A.: „Contact and thermal analysis of an alumina-steel dry sliding friction pair considering the surface roughness”, TRIBOLOGY INTERNATIONAL, Vol. 40, pp. 982-994 (2007) [2] Fekete, G.; Váradi, K.; Leali, M.; Bottarelli, F.: "Thermal FE analysis of a pneumatic cylinder„, Proceedings of sixth conference on mechanical engineering, ISBN 978-963-420-947-8, (2008) Department of Machine and Industrial Product Design

8. WEAR DETECTION AND SIMULATION GM research topics relating to this area : 101 Competence in: 1. FE wear simulation Department of Machine and Industrial Product Design

9. WEAR DETECTION AND SIMULATION 2. Modeling and interpretation of typicalwear mechanisms 3. Characterization of worn surfaces Present research activity of the department in this field: Hungarian National Scientific Research Foundation project: „Friction behaviour and failure mechanisms of polymer, elastomer, ceramic and composite structural components”, OTKA (NI 62729) References: [1] Kónya, L.; Váradi, K.: „Wear simulation of a polymer-steel sliding pair considering temperature- and time-dependent material properties”, in Friedrich, K.; Schlarb, A.K. (editors) „Tribology of Polymeric Nanocomposites”, TRIBOLOGY AND INTERFACE ENGINEERING SERIES, No. 55, Elsevier, (2008) ISBN 978-0-444-53155-1 Department of Machine and Industrial Product Design