Comparing theory with experimental data in studying the deformation of magnetically smart films deposited on nickel and glass substrates

Wang, Xiaoli; Cao, Jian; Ulmer, M. P.; Graham, Michael E.; Vaynman, Semyon; Savoie, Julia; Bellavia, Bridget

doi:10.1117/12.929350

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…2 As voltage is applied to the piezoelectric it forces an in-plane strain which then induces an out-of-plane displacement that can be used to adjust the mirror figure. Other technologies for actuation exist, for instance the magneto-strictive devices 6,7 or voice-coil actuators. 8 As long as the actuator has a useful operational range where the response is a unique and monotonic function of the input drive level then the analysis presented here applies.…”

Section: Actuatormentioning

confidence: 99%

Simulating correction of adjustable optics for an x-ray telescope

et al. 2012

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The next generation of large X-ray telescopes with sub-arcsecond resolution will require very thin, highly nested grazing incidence optics. To correct the low order figure errors resulting from initial manufacture, the mounting process, and the effects of going from 1 g during ground alignment to zero g on-orbit, we plan to adjust the shapes via piezoelectric "cells" deposited on the backs of the reflecting surfaces. This presentation investigates how well the corrections might be made. We take a benchmark conical glass element, 410×205 mm, with a 20×20 array of piezoelectric cells 19×9 mm in size. We use finite element analysis to calculate the influence function of each cell. We then simulate the correction via pseudo matrix inversion to calculate the stress to be applied by each cell, considering distortion due to gravity as calculated by finite element analysis, and by putative low order manufacturing distortions described by Legendre polynomials. We describe our algorithm and its performance, and the implications for the sensitivity of the resulting slope errors to the optimization strategy.

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Section: Actuatormentioning

confidence: 99%

Simulating correction of adjustable optics for an x-ray telescope

et al. 2012

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“…Terfenol-D™ or similar magnetostrictive materials with large magnetostrictive strains, possess favorable properties of large force capacity, high resolution and fast response. Based on these reasons, these materials are considered to be deposited on the non-reflecting side of lightweight x-ray telescope mirrors to correct the mirror surface profiles by appropriate actuation driven by the magnetic field [6][7][8][9]. In this application, the deformation of magnetostrictive film-substrate systems is expected to be controlled by varying the direction and the strength of the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Deformation of rectangular thin glass plate coated with magnetostrictive material

Wang¹,

Yao²,

Liu³

et al. 2016

Smart Mater. Struct.

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As magnetic smart materials (MSMs), magnetostrictive materials have great potential to be selected as coating materials for lightweight x-ray telescope mirrors due to their capability to tune the mirror profile to the desired shape under a magnetic field. To realize this potential, it is necessary to study the deformation of the mirror substrate with the MSM coating subjected to a localized magnetic field. In this paper, an analytical model is developed to calculate the deformation of rectangular coated samples locally affected by magnetostrictive strains driven by an external magnetic field. As a specific case to validate the model, a square glass sample coated with MSMs is prepared, and its deformation is measured in a designed experimental setup by applying a magnetic field. The measured deformation of the sample is compared with the results calculated from the analytical model. The comparison results demonstrate that the analytical model is effective in calculating the deformation of a coated sample with the localized mismatch strains between the film and the substrate. In the experiments, different shape patterns of surface profile changes are achieved by varying the direction of the magnetic field. The analytical model and the experimental method proposed in this paper can be utilized to further guide the application of magnetostrictive coating to deformable lightweight x-ray mirrors in the future.

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“…The Northwestern team electroforms nickel mirrors that serve as the high-coercivity ferromagnetic substrate, sputters a magnetostrictive material onto the back of the mirror, measures the magneto-active deformation using a white-light interferometer in tandem with the magnetic writing head (Figure 13 right), and compares experimental results with FEA predictions 41 . Figure 13.…”

Section: Magnetic Writingmentioning

confidence: 99%

Toward active x-ray telescopes II

et al. 2012

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In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the observation time required to achieve a given sensitivity has decreased by eight orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope, culminating with the exquisite subarcsecond imaging performance of the Chandra X-ray Observatory. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (> 1 m 2 ) and comparable or finer angular resolution (< 1″). Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challenging-requiring precision fabrication, alignment, and assembly of large areas (> 200 m 2 ) of lightweight (≈ 1 kg m -2 areal density) mirrors. Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes current progress toward active x-ray telescopes.

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Comparing theory with experimental data in studying the deformation of magnetically smart films deposited on nickel and glass substrates

Cited by 4 publications

References 12 publications

Simulating correction of adjustable optics for an x-ray telescope

Simulating correction of adjustable optics for an x-ray telescope

Deformation of rectangular thin glass plate coated with magnetostrictive material

Toward active x-ray telescopes II

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