High Resolution Characterization of Materials Used in Packages Through Digital Image Correlation

2005 ◽  
Author(s):  
V. Srinivasan ◽  
S. Radhakrishnan ◽  
X. Zhang ◽  
G. Subbarayan ◽  
T. Baughn ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Full Field ◽  
Dependent Behavior ◽  
Very High Spatial Resolution ◽  
Speckle Patterns ◽  
Materials Used ◽  
Characterization Of Materials

In this study, we demonstrate a simple, full field displacement characterization technique based on digital image correlation (DIC). We develop a robust correlation measure implemented in a code and use it to characterize materials at high spatial and displacement resolution. We describe the methods implemented in the DIC code and compare against those available in the literature. We show how sample preparation may be entirely eliminated by using the natural speckle inherent in specular (rough) surfaces. We demonstrate further that the use of natural speckle enables very high spatial resolution (100 microns or less) since creating artificial speckle patterns in miscroscale spatial regions is a significant challenge. The software is also designed to be robust to varying contrasts between the deformed and the undeformed images. Its accuracy is enhanced by using NURBS (Non-Uniform Rational B-Spline) as the interpolating function in the code. We demonstrate the developed software and the underlying procedure on several packaging problems of interest. We measure the CTE of Alumina (Al2O3) using its natural speckle, we calculate the strain and therefore the modulus during mechanical testing of composite materials and we characterize the time dependent behavior of a micro-fiber reinforced composite (RT/Duroid) at high temperature.

Characterization of LIGA Microsystems Using Digital Image Correlation Technique and SEM Imaging

Aerospace ◽  
2005 ◽  
Author(s):  
Helena (Huiqing) Jin ◽  
Wei-Yang Lu ◽  
Jeff Chames ◽  
Nancy Yang
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Speckle Pattern ◽  
Image Correlation ◽  
Specimen Surface ◽  
Correlation Technique ◽  
Sem Images ◽  
Full Field ◽  
Speckle Patterns ◽  
Dic Technique

A new experimental technique was developed to characterize the mechanical properties of LIGA (an acronym from German words for lithography, electroplating, and molding) materials. An advanced imaging capability, scanning electron microscopy (SEM), with an integrated loading stage allows the acquisition of in situ microstructural images at the micro scale during loading. The load is measured directly from a load cell, and the displacement field is calculated from the SEM images based on the digital image correlation (DIC) technique. The DIC technique is a full-field deformation measurement technique which obtains displacement fields by comparing random speckle patterns on the specimen surface before and after deformation. The random speckle patterns are typically generated by applying a thin layer of material with high contrast to a specimen surface. Alternatively, DIC can also be applied using the microstructural features of a surface as texture patterns for correlation. DIC technique is ideally suited to characterize the deformation field of MEMS structures without the need to generate a random speckle pattern, which can be very challenging on the micro and nanoscale. In this paper, the technique is experimentally demonstrated on a LIGA specimen. The digital images showing LIGA surface features acquired during the loading can serve as random patterns for the DIC method. Therefore, full-field displacement and strain can be obtained directly on the specimen and the errors incurred by the testing system can be eliminated.

scholarly journals Analysis of Strain Field Heterogeneity at the Microstructure Level and Inverse Identification of Composite Constituents by Means of Digital Image Correlation

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 287 ◽  
Author(s):  
Witold Ogierman ◽  
Grzegorz Kokot
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Field ◽  
Optimization Procedure ◽  
Image Correlation ◽  
Inverse Identification ◽  
Full Field ◽  
Speckle Patterns ◽  
Measured Strain ◽  
Speckle Size

The present paper is devoted to the theoretical study on the estimation of the full-field strain at the microstructural level of composite materials by means of Digital Image Correlation (DIC). The main aim of the paper is to investigate the influence of speckle size on the accuracy of the strain field measurement at the microscale. The DIC analysis was conducted based on artificial speckle patterns generated numerically and the deformation behavior of the composites was simulated by using the finite element method (FEM). This approach gives the opportunity to compare the results of the DIC in terms of speckle size with the reference FEM solution. Moreover, the paper focuses on the inverse identification of the material constants of the composite constituents by using information associated with the measured strain field. The inverse problem is solved by using a novel two-step optimization procedure, which reduces the problem complexity. The feasibility and accuracy of the proposed approach are presented by analysis of two exemplary microgeometries representing the microstructures of fiber reinforced composites.

scholarly journals Experimental Characterization of the FRCM-Concrete Interface Bond Behavior Assisted by Digital Image Correlation

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1154
Author(s):  
Dario De Domenico ◽  
Antonino Quattrocchi ◽  
Damiano Alizzio ◽  
Roberto Montanini ◽  
Santi Urso ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Front Face ◽  
Full Field ◽  
Bond Behavior ◽  
Externally Bonded ◽  
Strengthening Technique ◽  
Concrete Interface

Digital Image Correlation (DIC) provides measurements without disturbing the specimen, which is a major advantage over contact methods. Additionally, DIC techniques provide full-field maps of response quantities like strains and displacements, unlike traditional methods that are limited to a local investigation. In this work, an experimental application of DIC is presented to investigate a problem of relevant interest in the civil engineering field, namely the interface behavior between externally bonded fabric reinforced cementitious mortar (FRCM) sheets and concrete substrate. This represents a widespread strengthening technique of existing reinforced concrete structures, but its effectiveness is strongly related to the bond behavior between composite fabric and underlying concrete. To investigate this phenomenon, a set of notched concrete beams are realized, reinforced with FRCM sheets on the bottom face, subsequently cured in different environmental conditions (humidity and temperature) and finally tested up to failure under three-point bending. Mechanical tests are carried out vis-à-vis DIC measurements using two distinct cameras simultaneously, one focused on the concrete front face and another focused on the FRCM-concrete interface. This experimental setup makes it possible to interpret the mechanical behavior and failure mode of the specimens not only from a traditional macroscopic viewpoint but also under a local perspective concerning the evolution of the strain distribution at the FRCM-concrete interface obtained by DIC in the pre- and postcracking phase.

MECHANICAL CHARACTERIZATION OF MATERIALS AND DIAGNOSIS OF STRUCTURES BY INVERSE ANALYSES: SOME INNOVATIVE PROCEDURES AND APPLICATIONS

2014 ◽  
Vol 11 (03) ◽  
pp. 1343002 ◽  
Author(s):  
GIULIO MAIER ◽  
VLADIMIR BULJAK ◽  
TOMASZ GARBOWSKI ◽  
GIUSEPPE COCCHETTI ◽  
GIORGIO NOVATI
Keyword(s):  
Structural Analysis ◽  
Digital Image Correlation ◽  
Residual Stresses ◽  
Mechanical Characterization ◽  
Image Correlation ◽  
Alkali Silica Reaction ◽  
Compression Tests ◽  
Material Models ◽  
Characterization Of Materials

A survey is presented herein of some recent research contributions to the methodology of inverse structural analysis based on statical tests for diagnosis of possibly damaged structures and for mechanical characterization of materials in diverse industrial environments. The following issues are briefly considered: identifications of parameters in material models and of residual stresses on the basis of indentation experiments; mechanical characterization of free-foils and laminates by cruciform and compression tests and digital image correlation measurements; diagnosis, both superficially and in depth, of concrete dams, possibly affected by alkali-silica-reaction or otherwise damaged.

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