Bulge Testing Transparent Thin Films with Moiré Deflectometry

Xu, Dong-Hui; Liechti, Kenneth M.

doi:10.1007/s11340-009-9291-0

Cited by 28 publications

(25 citation statements)

References 30 publications

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“…10 16/3 (8/3)*0.976/(1+ν) Energy minimization Beams 15 4.0 8/3 ≈ 2.67 Spherical cap Bromley et al 16 Lin 17 4.0 (7−ν)/3 Energy minimization Hohlfelder 21 4.0 (8/3)*(1.015 − 0.247 ν) Num. approximation Pan et al 22 4.0 (8/3)/(1.026 + 0.233 ν) F E M Small and Nix 18 4.0 8/3 (see text) FEM Bonnotte 19 16/3 4.0 (8/3)*(1.08 − 0.3 ν) for h/t ≥10 FEM Xu and Liechti 23 4.0 2 Spherical cap and Timoshenko and Woinowsky-Krieger 10 investigated the large deflections of uniformly loaded circular plates with clamped edge using an energy minimization approach. The general solution for the deflection of a circular membrane under pressure was adapted to the case of pre-stressed membranes by Vlassak.…”

Section: A Deflection Of Circular Membranes Under Pressurementioning

confidence: 98%

Comparison of two experimental methods for the mechanical characterization of thin or thick films from the study of micromachined circular diaphragms

Malhaire

2012

Review of Scientific Instruments

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The purpose of this study was to compare two experimental methods and evaluate the effectiveness of a set of analytical models in order to measure the initial stress and the Young's modulus value of thin and thick film materials. Two types of experiments were performed on micromachined circular diaphragms: bulge testing and vibrometry. The range of validity and accuracy of the analytical models with respect to the vibration of the diaphragms was discussed from the finite element simulations. It was shown that the a/t ratio should be considered carefully to determine the value of the Young's modulus by vibrometry with an acceptable error. A relative error of approximately ±10% on E was obtained for a/t ≤ 750. For 750 ≤ a/t ≤ 1000, the value of the dimensionless parameter k must also be considered. It has been shown that the residual stress value can be obtained with an accuracy of 10% or less, given that k > 12. As an illustration, experimental methods and models were applied to the characterization of a thick electroplated gold film and a sputter-deposited Inconel thin film. Circular structures were defined by vertical sidewalls etched on the back of a Si wafer using the deep reactive ion etching technique. In addition to analytical models, parametric finite element simulations and a design optimization technique were used to determine the material's mechanical properties. The static deflections of the diaphragms were measured as a function of the applied pressure. The resonant frequencies and mode shapes of the vibrating structures were observed under vacuum by white-light interferometric microscopy. For gold, it was found that E = (53 ± 20) GPa and σ0 = (180 ± 10) MPa. For Inconel, it was found that E = (157 ± 14) GPa and σ0 = (172 ± 5) MPa.

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Section: A Deflection Of Circular Membranes Under Pressurementioning

confidence: 98%

Comparison of two experimental methods for the mechanical characterization of thin or thick films from the study of micromachined circular diaphragms

Malhaire

2012

Review of Scientific Instruments

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“…Concerning bulge-test, the mechanical properties are extracted from the relationship between the applied pressure P and the corresponding maximum out-of-plane deflection h of the bulged circular membrane [7]:…”

Section: Resultsmentioning

confidence: 99%

Inﬂuence of microstructure and internal stress on the mechanical behavior of electroplated gold freestanding thin ﬁlms

Martegoutte

Seguineau²,

Fourcade

et al. 2010

EPJ Web of Conferences

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Abstract. Mechanical properties of freestanding electroplated gold thin films were studied in relationship to their geometrical and microstructural properties. Three different techniques of characterization were used: nanoindentation, bulge tests and microtensile tests. Results were compared to literature and also discussed according to physical phenomena related to the elaboration process of the specimens like seed layer exodiffusion or internal stress state. The observed plasticity and failure mechanisms were found to be in good agreement with the literature and are consistent with the microstructure. The measured Young's modulus is slightly higher than expected, and SIMS analysis is exploited to explain such a high value.

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“…One potential solution is the use of open-mold thermoforming equipment and full-field strain computation techniques to characterize the thermomechanical behavior of thermoplastics. In the field of experimental mechanics, the whole-field optical techniques have an advantage of being fast and contact-less [1,2]. In particular, stereo-DIC is more and more applied in thermoforming to compute whole-field strains [3], investigate thermoformability limits [4] and compute full-field thickness maps [5].…”

Section: Introductionmentioning

confidence: 99%

A comprehensive study of bubble inflation in vacuum-assisted thermoforming based on whole-field strain measurements

Ayadi¹,

Lacrampe²,

Krawczak³

2018

AIP Conference Proceedings

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Abstract. This paper focuses on the potential use of stereo-DIC in thermoforming conditions to monitor large deformations of softened thermoplastic sheets posteriori to the sagging phenomenon. The study concerns HIPS sheets which are softened by the radiative heat-transfer mode then stretched by inflation of compressed-air for 1.5 s to form a large and quasi-spherical dome of 250 mm in diameter. While the bubble-inflation operation leads to large deformations of the softened sheet, it shows transitional geometrical instabilities due to the initial surface sagging. When the temperature-induced surface deformations are inaccessible by the stereoscopic system during the heating operation, the geometrical instabilities limit the identification of the reference of displacements which affects the accuracy of results based on image-correlation computations. To compare between the principal strains assessed from bubble-inflation tests conducted at different thermal conditions, a method for filtering these instabilities is developed in this study.

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Bulge Testing Transparent Thin Films with Moiré Deflectometry

Cited by 28 publications

References 30 publications

Comparison of two experimental methods for the mechanical characterization of thin or thick films from the study of micromachined circular diaphragms

Comparison of two experimental methods for the mechanical characterization of thin or thick films from the study of micromachined circular diaphragms

Inﬂuence of microstructure and internal stress on the mechanical behavior of electroplated gold freestanding thin ﬁlms

A comprehensive study of bubble inflation in vacuum-assisted thermoforming based on whole-field strain measurements

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