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Analysis Of Core Buckling Defects In Sheet Metal Coil Processing, P.M. Lin, Jonathan A. Wickert
Analysis Of Core Buckling Defects In Sheet Metal Coil Processing, P.M. Lin, Jonathan A. Wickert
Jonathan A. Wickert
The elastic stability of a wound coil comprising a central core and many layers of sheet metal is modeled and analyzed. A common failure mode resulting from unfavorable internal stresses—called v-buckling—is characterized by a section of the core buckling inward, possibly with several nearby sheet metal layers. In the present study, the core is modeled as a thin cylinder that is subjected to (i) the uniform external pressure generated by the coil's wound-in stresses and (ii) a nonuniform elastic foundation around its circumference that represents core-coil contact or loss thereof. The model and an iterative numerical technique are used to …
Vibration Of Flex Circuits In Hard Disk Drives, Jonathan A. Wickert
Vibration Of Flex Circuits In Hard Disk Drives, Jonathan A. Wickert
Jonathan A. Wickert
A flex circuit connects the stationary electronic components in a hard disk drive to the rotating arm that carries the read/write heads and positions them above data tracks on the disk. Flex circuits are conventionally formed as a laminate of polyimide substrate, adhesive, and copper conductors. Deformation of a flex circuit is discussed in the context of the following stages: the initial unstressed shape, configurations in which stresses set and relax in response to elevated temperature, equilibrium, and small amplitude vibration. The model involves displacements of the flex circuit in the directions tangent and normal to the local equilibrium shape, …
Three-Dimensional Landau Theory For Multivariant Stress-Induced Martensitic Phase Transformations. Iii. Alternative Potentials, Critical Nuclei, Kink Solutions, And Dislocation Theory, Valery I. Levitas, Dean L. Preston, Dong Wook Lee
Three-Dimensional Landau Theory For Multivariant Stress-Induced Martensitic Phase Transformations. Iii. Alternative Potentials, Critical Nuclei, Kink Solutions, And Dislocation Theory, Valery I. Levitas, Dean L. Preston, Dong Wook Lee
Valery I. Levitas
In part III of this paper, alternative Landau potentials for the description of stress-and temperature-induced martensitic phase transformations under arbitrary three-dimensional loading are obtained. These alternative potentials include a sixth-degree (2-4-6) polynomial in Cartesian order parameters and a potential in hyperspherical order parameters. Each satisfies all conditions for the correct description of experiments. The unique features of the potentials are pointed out and a detailed comparison of the potentials is made for NiAl alloy. Analytic solutions of the one-dimensional time-independent Ginzburg-Landau equations for the 2-3-4 and 2-4-6 potentials for a constant-stress tensor and invariant-plane strain are obtained and compared. Solutions …