On the qualitative dynamics of rotating disks: Thermal shocks and structural integrity

Within engineering circles, overriding breakthroughs have allowed rotating mechanisms to be safely embedded under severe operational circumstances as well as harsh loads. Meanwhile, a literature survey reflects that the implementation of functionally graded materials (FGMs) has revolutionized the characteristics of rotating disks in industrial segments. One of the most challenging situations for FG rotating disks is exposure to multi-dimensional thermal shocks during heating (ascendant) and cooling (descendant), when even materials with high fracture resistance may become deficient. In this paper, a general picture is drawn of a transient thermoelastic design of FG rotating disks to mitigate failure issues stemming from ascendant/descendant thermal gradients and body forces. Contrary to the majority of reports, thermal and displacement fields of the rotating system are affected in both radial and circumferential paths in the polar system, indicating the need for two-dimensional analysis of transient heat transfer. Material properties of the geometry can be judiciously chosen in the r and theta directions, underpinning a practical recipe in the load-bearing capacity of the model for in-situ applications. Transient numerical simulations of deflections, stresses, and thermal fields of a circular annular disk are graphically elaborated using the Fourier and polynomial differential quadrature approaches. On the basis of awareness of the nature of the applied loads, it is found that an appropriate selection criterion of the variation of the material properties from among all available candidates noticeably ameliorates the impact of temperature shocks on the centrifugal force of the rotary system. With regard to the yielding criteria of the structures, the outcomes of the proposed study extend the boundaries of current traditional designs, demonstrating parallel progress in theories and viable materials.