Apparatus for Determining the Viscoelastic Properties of Materials Over Ten Decades of Frequency and Time

In the present paper, a reliability of a single-sided chip-size package (CSP) manufactured using a non-conductive adhesive stud bump direct interconnection method is investigated. The reliability of the CSP is closely related with normal stress between an IC chip and a gold bump. Total normal stress can be decomposed into two parts, deflection related and thermal expansion related. The deflection for a three-layered plate, which is taken into account viscoelastic properties for the resin-sealed sheet and the substrate, respectively, is calculated and compared with experimental results on the deflection of the single-sided CSP. A relationship between the normal stress and the curvature derived from deflection is deduced. Through the use of this relationship, the variation of normal stress with the heat cycle is obtained considering the viscoelastic properties of materials. Furthermore, a relaxation behavior for the thermal stress in the resin-sealed sheet between two rigid walls considering its viscoelastic property is investigated. Summing up normal stresses for each calculation yields the normal stress between the IC and the bump. A relationship between the normal stress and the life of single-sided CSP is investigated for heat cycle. The life in experiment can be explained by the relaxation in the normal stress and the amplitude of the normal stress.

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On the Applicability of Sneddon's Solution for Interpreting the Indentation of Nonlinear Elastic Biopolymers

Journal of Applied Mechanics ◽

10.1115/1.4027973 ◽

2014 ◽

Vol 81 (9) ◽

Cited By ~ 14

Author(s):

Man-Gong Zhang ◽

Jinju Chen ◽

Xi-Qiao Feng ◽

Yanping Cao

Keyword(s):

Elastic Properties ◽

Viscoelastic Properties ◽

Contact Theory ◽

Elastic Contact ◽

Flat Punch ◽

Linear Elastic ◽

Contact Models ◽

Properties Of Materials ◽

Nonlinear Elastic ◽

Viscoelastic Contact

Indentation has been widely used to characterize the mechanical properties of biopolymers. Besides Hertzian solution, Sneddon's solution is frequently adopted to interpret the indentation data to deduce the elastic properties of biopolymers, e.g., elastic modulus. Sneddon's solution also forms the basis to develop viscoelastic contact models for determining the viscoelastic properties of materials from either conical or flat punch indentation responses. It is worth mentioning that the Sneddon's solution was originally proposed on the basis of linear elastic contact theory. However, in both conical and flat punch indentation of compliant materials, the indented solid may undergo finite deformation. In this case, the extent to which the Sneddon's solution is applicable so far has not been systematically investigated. In this paper, we use the combined theoretical, computational, and experimental efforts to investigate the indentation of hyperelastic compliant materials with a flat punch or a conical tip. The applicability of Sneddon's solutions is examined. Furthermore, we present new models to determine the elastic properties of nonlinear elastic biopolymers.

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Determination of Viscoelastic Properties of Materials Using a Spectrum Function

47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference<BR> 14th AIAA/ASME/AHS Adaptive Structures Conference<BR> 7th ◽

10.2514/6.2006-2248 ◽

2006 ◽

Author(s):

Rani Sullivan

Keyword(s):

Viscoelastic Properties ◽

Spectrum Function ◽

Properties Of Materials

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Optimizing signal collection efficiency of the VIPA-based Brillouin spectrometer

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545815500212 ◽

2015 ◽

Vol 08 (04) ◽

pp. 1550021 ◽

Cited By ~ 34

Author(s):

Zhaokai Meng ◽

Vladislav V. Yakovlev

Keyword(s):

Optical Imaging ◽

Background Noise ◽

Viscoelastic Properties ◽

Collection Efficiency ◽

Signal Loss ◽

Brillouin Spectroscopy ◽

Strong Signal ◽

Direct Assessment ◽

Signal Collection ◽

Properties Of Materials

Brillouin spectroscopy is an emerging tool for microscopic optical imaging as it allows for noninvasive and direct assessment of the viscoelastic properties of materials. Recent advances of background-free confocal Brillouin spectrometer allows investigators to acquire the Brillouin spectra for turbid samples as well as transparent ones. However, due to strong signal loss induced by the imperfect optical setup, the Brillouin photons are usually immersed in background noise. In this report, we proposed and experimentally demonstrated multiple approaches to enhance the signal collection efficiency. A signal enhancement by > 4 times can be observed, enabling observation of ultra-weak signals.

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