Journal Article•
Buckling of fiber-reinforced annular disks subjected to a concentrated tangential edge load
01 Oct 2011-Journal of Emerging Trends in Engineering and Applied Sciences (Scholarlink Research Institute)-Vol. 2, Iss: 5, pp 835-839
TL;DR: In this article, the buckling behavior of polar and rectangular orthotropic annular disks subjected to a concentrated tangential load acting on the outer edge was analyzed. But some aspects of their buckling behaviour have not been addressed.
Abstract: Circular and annular disks are one of the most commonly used shapes of components in machinery and hence the behavior of these is of utmost interest. Consequently, we find that circular disks have been analyzed extensively. Yet some aspects of their buckling behavior have not been addressed. The aim of the present work is to analyze polar and rectangular orthotropic annular disks subjected to a concentrated tangential load acting on the outer edge. The effect of variation in dimensions, elastic properties, point of load application and number of layers with different fiber orientations is considered. Non-dimensionalized results are presented in the form of graphs and an attempt is made to analyze the observed behavior.
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TL;DR: In this article, a generalized formulation for the in-plane modal characteristics of circular annular disks under combinations of all possible classical boundary conditions is presented, and the natural frequencies are tabulated and compared with data available in the literature.
58 citations
TL;DR: In this article, a nonlinear stability analysis of a realistic disk brake model with 12 degrees of freedom was performed using center manifold theory and artificially increasing the degree of degeneracy of the occurring bifurcation.
Abstract: It has become commonly accepted by scientists and engineers that brake squeal is generated by friction-induced self-excited vibrations of the brake system. The noise-free configuration of the brake system loses stability through a flutter-type instability and the system starts oscillating in a limit cycle. Usually, the stability analysis of disk brake models, both analytical as well as finite element based, investigates the linearized models, i.e. the eigenvalues of the linearized equations of motion. However, there are experimentally observed effects not covered by these analyses, even though the full nonlinear models include these effects in principle. The present paper describes the nonlinear stability analysis of a realistic disk brake model with 12 degrees of freedom. Using center manifold theory and artificially increasing the degree of degeneracy of the occurring bifurcation, an analytical expression for the turning points in the bifurcation diagram of the subcritical Hopf bifurcations is calculated. The parameter combination corresponding to the turning points is considered as the practical stability boundary of the system. Basic phenomena known from the operating experience of brake systems tending to squeal problems can be explained on the basis of the practical stability boundary.
54 citations
"Buckling of fiber-reinforced annula..." refers background in this paper
...Hochlenert (2009) describes the nonlinear stability analysis of a realistic disk brake model....
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TL;DR: In this paper, an analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is summarized.
Abstract: In this study an attempt is made to put into perspective the problem of a rotating disk, be it a single disk or a number of concentric disks forming a unit. An analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is summarized. Results of an extensive parametric study are presented to clearly define the key design variables and their associated influence. In general the important parameters were identified as misfit, mean radius, thickness, material property and/or load gradation, and speed; all of which must be simultaneously optimized to achieve the ‘best’ and most reliable design. Also, the important issue of defining proper performance/merit indices (based on the specific stored energy), in the presence of multiaxiality and material anisotropy is addressed. These merit indices are then utilized to discuss the difference between flywheels made from PMC and TMC materials with either an annular or solid geometry. Finally two major aspects of failure analysis, that is the static and cyclic limit (burst) speeds are addressed. In the case of static limit loads, a lower (first fracture) bound for disks with constant thickness is presented. The results (interaction diagrams) are displayed graphically in designer friendly format. For the case of fatigue, a representative fatigue/life master curve is illustrated in which the normalized limit speed versus number of applied cycles is given for a cladded TMC disk application.
54 citations
TL;DR: In this paper, the authors used the Rayleigh-Ritz method with simple polynomials as admissible functions for obtaining natural frequencies of transversely vibrating polar orthotropic annular plates.
50 citations
"Buckling of fiber-reinforced annula..." refers background in this paper
...Mermertas and Halek (1994) study annular plates under periodic radial forces acting on the inner as well as outer boundaries. Chen and Jhu (1996) analyze the stability of a spinning disk....
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...Mermertas and Halek (1994) study annular plates under periodic radial forces acting on the inner as well as outer boundaries....
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TL;DR: In this paper, the method of annular finite elements is applied to the case of varying thickness annular discs constructed of materials exhibiting polar orthotropic characteristics, and the numerical convergence of the method is tested and comparisons are made with the corresponding results obtained in other studies.
38 citations