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Full-Text Articles in Engineering
Corrugation And Buckling Defects In Wound Rolls, Jonathan A. Wickert, P.M. Lin
Corrugation And Buckling Defects In Wound Rolls, Jonathan A. Wickert, P.M. Lin
Jonathan A. Wickert
Sheet metal, paper, and polymer webs are often stored and processed as large rolls comprising thousands of layers. Depending on the elastic properties of the web material, the roll's dimensions, the type of core, and the winding tension, the stresses that develop within the roll can be sufficiently high to cause local or gross buckling defects to form. For instance, the cylindrical core onto which the web is wound can collapse, a failure mode that is termed "v-buckling." In other cases, while the core might remain intact, a group of layers interior to the roll can wrinkle into a near-sinusoidal …
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, …
Stress Field In Finite Width Axisymmetric Wound Rolls, Jonathan A. Wickert, Y.M. Lee
Stress Field In Finite Width Axisymmetric Wound Rolls, Jonathan A. Wickert, Y.M. Lee
Jonathan A. Wickert
A model is developed for predicting the stress field within a wound roll of web material, in which the radial, circumferential, transverse, and shear stresses can vary in both the roll's radial and cross-web (transverse) directions. As has been the case in previous wound roll stress analyses based on one-dimensional models, the present approach accounts for the anisotropic and nonlinear material properties of the layered web material, and the incremental manner in which the roll is wound. In addition, the present development accounts for arbitrary cross-sectional geometry and material of the core, and the presence of nonuniform tension across the …