Location of Repository

Shock isolation systems incorporating Coulomb friction

By Mohd Ismail

Abstract

This study investigates a novel approach to the problem of shock isolation. The questions considered are whether friction produces a better performance in terms of reduced response during a shock compared to viscous damping and a lower residual response after the shock.<br/><br/>To gain physical insight, a single degree of freedom model with friction applied to the isolated mass is analysed. It serves as a benchmark to the performance of a two degree of freedom model where friction is applied to a secondary mass. The isolation system performance is then quantified. For the two degree of freedom system with an intermediate secondary spring which connects the primary and secondary mass, it is possible to obtain the reduction in the displacement response as good as the single degree of freedom system and at the same time smoother acceleration response compared to the single degree of freedom system. For the purpose of further improvement, a control strategy is introduced to switch on and off friction in both models depending on some response parameters and this is compared to the passive systems. This is the semi active control strategy where friction is changed within a cycle of vibration (discontinuous). The control strategy provides more displacement reduction to ensure the maximum displacement response is much smaller than the base input which cannot be obtained with the passive systems.<br/><br/>The practical implementation and experimental validation is presented only for the first stage of the response during the shock. For the practical implementation of the switchable friction, an electromagnet is applied to separate the friction surfaces. Good agreement with the simple theoretical models for both passive and switchable systems is obtained. The reduced displacement and smooth acceleration response were obtained from the experiments with the system used to represent the two degree of freedom model. The issues and limitations in the practical implementation are identified and discussed

Topics: TL
Year: 2012
OAI identifier: oai:eprints.soton.ac.uk:348953
Provided by: e-Prints Soton

Suggested articles

Preview

Citations

  1. (2002). A comparative study and analysis of semi active vibration control systems. doi
  2. (2005). A comparison of semi active damping control strategies for vibration isolation of harmonic disturbances. doi
  3. A correlation coefficient for modal vector analysis,
  4. (2004). A general method for semi active feedback control of variable friction dampers. doi
  5. (1998). A historical review on dry-friction and stick-slip phenomena. Applied Mechanics Reviews, doi
  6. (2002). A Tutorial Introduction to Control Systems Development and Implementation with dSPACE.
  7. A.Ramaratnam, A switched stiffness approach for structural vibration control: theory and real time implementation. doi
  8. (2004). Analysis of a dry friction problem under small displacements: application to a bolted joint Wear, doi
  9. (1999). and A.K.Mallik, Performance of non linear isolators and absorbers to shock excitations. doi
  10. (1997). and A.Stokes, Semi active control of friction dampers. doi
  11. (2008). and C.Pierre, Transient in a two DOF nonlinear system. Nonlinear Dyn doi
  12. (2004). and H.Nijmeijer, Energy dissipation of a friction damper. doi
  13. (2005). and J.H.Kim, Feasibility study of a tunable friction damper. doi
  14. and M.J.Brennan, The effect of dual rate suspension damping on vehicle response to transient road inputs. doi
  15. and N.S.Ferguson, The effect of Coulomb friction on the residual vibration of a shock isolation system,
  16. (1974). and R.A.Harwood, Vibration control using semi active force generators. doi
  17. (2007). and S.Bjorklund, Friction models for sliding dry, boundary and mixed lubricated contacts. Tribology International, doi
  18. (2003). and W.L.He, Applications of some semiactive control systems to benchmark cable-stayed bridge. doi
  19. (1974). and W.Weaver, Vibration Problems in Engineering. doi
  20. (2000). and X.Song, No jerk semi active skyhook control method and apparatus.
  21. B.S.Heck, Semi active suspension using dry friction energy dissipation,
  22. (2000). C.S.Liu, Coulomb friction oscillator:modelling and responses to harmonic loads and base excitations. doi
  23. (2001). C.S.Liu, Non sticking oscillation formulae for Coulomb friction under harmonic loading. doi
  24. D.J.Ewins, Models of friction damping with variable normal load for time-domain analysis of vibrations,
  25. (2001). Dynamics of friction oscillators excited by a moving base and/or driving force. doi
  26. (1945). Dynamics of package cushioning. doi
  27. (1996). excited vibrations of a conservative duffing oscillator with application to shock protection in portable electronics. doi
  28. (2010). Experiment and analysis of a fuzzy controlled piezoelectric seismic isolation system. doi
  29. (1995). Finite Element Model Updating in Structural Dynamics. doi
  30. (1930). Forced vibrations with combined viscous and Coulomb damping. Philosophical Magazine, doi
  31. (1995). Friction damping and isolation systems. doi
  32. (2002). Friction modeling for dynamic system simulation. Applied Mechanics Reviews, doi
  33. (1992). Fundamentals of Vehicle Dynamics. doi
  34. (2009). H.Nijmeijer, Prediction and validation of the energy dissipation of a friction damper. doi
  35. (2000). Introduction to Experimental Nonlinear Dynamics. doi
  36. (2008). isolation using switchable stiffness, doi
  37. (1960). J.C.Snowdon, Incidence and prevention of damage due to mechanical shock. doi
  38. (2008). J.Hammond, Fundamentals of Signal Processing for Sound and Vibration Engineers.
  39. (2002). K.Y.Lam, Biodynamic response of shipboard sitting subject to ship shock motion. doi
  40. (1983). L.E.Hifnawy, Vibration of hammer foundations. Soil dynamics and earthquake engineering, doi
  41. (2004). M.Hesham, Response of block foundations to impact loads. doi
  42. (1997). Measurement and modeling of microslip for engineering surfaces in contact,
  43. (2011). Modified friction device for control of large-scale systems. Structural control and health monitoring, doi
  44. (1997). Modulated homogeneous friction: a semi active damping strategy. Earthquake Engineering and Structural Dynamics, doi
  45. (2004). N.M.Wereley. Shock isolation systems using magnetorheological dampers. doi
  46. (2007). Numerical simulation of the seismic behaviour of building structures equipped with friction energy dissipators. Computers and Structures, doi
  47. (2008). On dry friction modelling and simulation in kinematically excited oscillatory systems. doi
  48. (2004). On the control of the friction force. Meccanica, doi
  49. (1971). P.L.Rees, An optimum shock isolator. doi
  50. (2004). Predictive control of seismic structures with semi active friction dampers. Earthquake Engineering and Structural Dynamics, doi
  51. (2008). Predictive control of smart isolation system for precision equipment subjected to near fault earthquakes. Engineering Structures, doi
  52. (1995). R.J.Rogers, Equivalent viscous damping models of Coulomb friction in multi degree of freedom vibration systems. doi
  53. (1979). Response of a base excited system with Coulomb and viscous friction. doi
  54. (1961). Response of nonlinear shock mountings to transient foundation displacements. doi
  55. Response spectra analysis for undamped structural systems subjected to half-sine impact acceleration pulses. Microelectronics Reliability, doi
  56. (2000). Semi active control strategies for buildings subject to near-field earthquakes, doi
  57. (2007). Shock analysis of a head actuator assembly subjected to half sine acceleration pulses. doi
  58. (1963). state and transient behavior of two and three element isolation mountings. doi
  59. (1997). Study of dry friction under small displacements and near zero sliding velocity. Wear, doi
  60. (1997). T.Davis, Representations of Coulomb friction for dynamic analysis. Earthquake Engineering and Structural Dynamics, doi
  61. (1998). T.Sireteanu, Vibration control of machines by use of semi active dry friction damping. doi
  62. (2009). T.X.Yu, Analytical models for shock isolation of typical components in portable electronics. doi
  63. (2011). Testing and modeling of shock mitigating seats for high speed craft.
  64. (1965). The anti-shock mounting of testing machines. doi
  65. (2005). The effect of suspension damping on vehicle response to transient road inputs, MPhil thesis Institute of Sound and Vibration Research.
  66. (1958). The intrinsic variables affecting the stick-slip process. Proc.Phys Soc., doi
  67. (2006). The pulse width effect of single half sine acceleration pulse on the peak response of an actuator arm of hard disk drive. doi
  68. (1962). Transient response of nonlinear isolation mountings to pulselike displacements. doi
  69. Vibration reduction and isolation performance for on off control of a friction force at a spring support doi
  70. (2002). W.T.Chang, Frictional behaviour of a belt driven and periodically excited oscillator. doi
  71. (2007). Y.L.Xu, Semi active control of a building complex with variable friction dampers. Engineering Structures, doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.