Analysis of thermomechanical phenomena in multidisc clutches and brakes

Zagrodzki, Przemysław

doi:10.1016/0043-1648(90)90091-n

Cited by 143 publications

(63 citation statements)

References 5 publications

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“…(9). In other words, at the end of each time step we need to re-expand the instantaneous temperature ÿeld as a series of the eigenfunctions appropriate to the next time step.…”

Section: Nature Of the Approximationmentioning

confidence: 99%

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Transient solution of a thermoelastic instability problem using a reduced order model

Al-Shabibi

Barber

2002

International Journal of Mechanical Sciences

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Above a certain critical speed, sliding systems with frictional heating such as brakes and clutches can exhibit thermoelastic instability in which non-uniform perturbations develop in the pressure and temperature ÿelds. A method is described in which the transient thermomechanical behaviour of such systems is approximated by a reduced order model, describing one or more dominant perturbations or eigenfunctions. The goal is to construct a mathematical model of the system with a modest number of degrees of freedom.If a single dominant perturbation is used, an integral expression can be written for the evolution of the perturbation with time. A more accurate description involving several terms requires that the transient behaviour be generated by a sequence of operations in which the sliding speed is piecewise constant. Both models are evaluated by comparison with a direct numerical simulation and prove to give good accuracy with a dramatic reduction in computing time. ?

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“…(9). In other words, at the end of each time step we need to re-expand the instantaneous temperature ÿeld as a series of the eigenfunctions appropriate to the next time step.…”

Section: Nature Of the Approximationmentioning

confidence: 99%

“…These e ects might be simulated by ÿnite element analysis [9,10], but transient simulations are very computer intensive. In the present paper, we explore some simpler approximate methods analogous to reduced order models used in the analysis of complex dynamic systems and based on the concept of a truncated eigenfunction expansion.…”

Section: Introductionmentioning

confidence: 99%

Transient solution of a thermoelastic instability problem using a reduced order model

Al-Shabibi

Barber

2002

International Journal of Mechanical Sciences

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“…However, there is a clear need for a method that will account for other features of the system geometry, such as the nite width of the sliding surface, the axisymmetric geometry of the disc, and the`hat' section used to attach the disc to its support. One approach is to use nite-element analysis (FEA) to solve the coupled transient thermoelastic contact problem in time (Zagrodzki 1990;Johansson 1993;Zagrodzki et al 1999). This method is extremely ®exible, in that it can accommodate nonlinear or temperature-dependent constitutive behaviour, more realistic friction laws, and practical loading cycles.…”

Section: (B) the E® Ect Of Geometrymentioning

confidence: 99%

“…Hot spots can cause material damage and wear and are also a source of undesirable frictional vibrations, known in the automotive disc brake community as`hot roughness' or`hot judder' (Kreitlow et al . 1985;Inoue 1986;Zagrodzki 1990;Anderson & Knapp 1990;Lee & Dinwiddie 1998). Figure 1 shows one of the plates of a typical multi-disc wet clutch after a period of normal service.…”

Section: Introductionmentioning

confidence: 99%

Eigenvalue solution of thermoelastic instability problems using Fourier reduction

Barber

Zagrodzki³

2000

Proc. R. Soc. Lond. A

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114

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A nite-element method is developed for determining the critical sliding speed for thermoelastic instability of an axisymmetric clutch or brake. Linear perturbations on the constant-speed solution are sought that vary sinusoidally in the circumferential direction and grow exponentially in time. These factors cancel in the governing thermoelastic and heat-conduction equations, leading to a linear eigenvalue problem on the two-dimensional cross-sectional domain for the exponential growth rate for each Fourier wavenumber. The imaginary part of this growth rate corresponds to a migration of the perturbation in the circumferential direction.The algorithm is tested against an analytical solution for a layer sliding between two half-planes and gives excellent agreement, for both the critical speed and the migration speed. Criteria are developed to determine the mesh re nement required to give an adequate discrete description of the thermal boundary layer adjacent to the sliding interface. The method is then used to determine the unstable mode and critical speed in geometries approximating current multi-disc clutch practice.

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“…However, it is well known that heat may show significant influence on the contact interface. Frictional heating generation will be a subject of concern to us when conventional ferrous materials are used in automotive brakes and clutches [24][25][26][27]. When brakes are applied to a moving system, the kinetic energy will be transformed into heat energy, which does not dissipate fast enough into the air stream.…”

Section: Introductionmentioning

confidence: 99%

Thermo-contact mechanics of a rigid cylindrical punch sliding on a finite graded layer

Chen

Peng

2012

Acta Mech

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A steady-state thermo-contact model of a rigid insulated cylinder of radius R sliding on a finite graded elastic layer is studied, whose Young's modulus, thermal conductivity coefficient and thermal expansion coefficient vary exponentially in the thickness direction. The transfer matrix method and Fourier integral transform technique are used to obtain a Cauchy-type singular integral equation for the contact stresses. Numerical calculation yields the interface traction and temperature distributions below the rigid punch. It shows that crack damage in the finite graded layer due to the frictional sliding can be prevented by several alternative ways, such as decreasing the shear modulus ratio of the surface to the bottom, decreasing the friction coefficient, increasing the thickness of the finite graded layer, increasing the thermal conductivity coefficient ratio of the surface to the bottom or increasing the sliding velocity. The finding should be very useful for the design of novel graded materials with potential applications in aerospace, tribology, coatings, etc.

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Analysis of thermomechanical phenomena in multidisc clutches and brakes

Cited by 143 publications

References 5 publications

Transient solution of a thermoelastic instability problem using a reduced order model

Transient solution of a thermoelastic instability problem using a reduced order model

Eigenvalue solution of thermoelastic instability problems using Fourier reduction

Thermo-contact mechanics of a rigid cylindrical punch sliding on a finite graded layer

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