Underwater mechanical behavior of closed cell PVC foams under hydrostatic loading through 3D DIC technique

2019 ◽  
Vol 73 ◽  
pp. 72-81 ◽  
Author(s):  
Koray Senol ◽  
Arun Shukla
Keyword(s):  
Mechanical Behavior ◽  
Hydrostatic Loading ◽  
Closed Cell ◽  
Dic Technique

scholarly journals Mechanical Response of Castlegate Sandstone under Hydrostatic Cyclic Loading

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
William M. Kibikas ◽  
Stephen J. Bauer
Keyword(s):  
Cyclic Loading ◽  
Mechanical Behavior ◽  
Loading Rate ◽  
Confining Pressure ◽  
Petrophysical Properties ◽  
Loading Conditions ◽  
Hydrostatic Loading ◽  
Stress Cycling ◽  
Stress Cycles ◽  
Static Conditions

The stress history of rocks in the subsurface affects their mechanical and petrophysical properties. Rocks can often experience repeated cycles of loading and unloading due to fluid pressure fluctuations, which will lead to different mechanical behavior from static conditions. This is of importance for several geophysical and industrial applications, for example, wastewater injection and reservoir storage wells, which generate repeated stress perturbations. Laboratory experiments were conducted with Castlegate sandstone to observe the effects of different cyclic pressure loading conditions on a common reservoir analogue. Each sample was hydrostatically loaded in a triaxial cell to a low effective confining pressure, and either pore pressure or confining pressure was cycled at different rates over the course of a few weeks. Fluid permeability was measured during initial loading and periodically between stress cycles. Samples that undergo cyclic loading experience significantly more inelastic (nonrecoverable) strain compared to samples tested without cyclic hydrostatic loading. Permeability decreases rapidly for all tests during the first few days of testing, but the decrease and variability of permeability after this depend upon the loading conditions of each test. Cycling conditions do affect the mechanical behavior; the elastic moduli decrease with the increasing loading rate and stress cycling. The degree of volumetric strain induced by stress cycles is the major control on permeability change in the sandstones, with less compaction leading to more variation from measurement to measurement. The data indicate that cyclic loading degrades permeability and porosity more than static conditions over a similar period, but the petrophysical properties are dictated more by the hydrostatic loading rate rather than the total length of time stress cycling is imposed.

Tensile and Fracture Characterization of PVC Foam Cores

2001 ◽  
Author(s):  
Gilmer M. Viana ◽  
Leif A. Carlsson
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
Brittle Material ◽  
Failure Process ◽  
Material Behavior ◽  
Strain Response ◽  
Fracture Characterization ◽  
Closed Cell

Abstract Mechanical behavior in tension and fracture toughness of cross-linked PVC foams have been characterized. Young’s modulus, yield strength and fracture toughness data were compared to micro-structural relations derived for open and closed-cell foams. The failure process and stress strain response were indicative of brittle material behavior.

Solder Joint Reliability in Underfilled Flip Chip Package With a Consideration of Chip-Package-Interaction (CPI)

2011 ◽  
Author(s):  
Jae B. Kwak ◽  
Da Yu ◽  
Tung T. Nguyen ◽  
Seungbae Park
Keyword(s):  
Mechanical Behavior ◽  
Flip Chip ◽  
Thermal Loading ◽  
Solder Bump ◽  
Image Correlation ◽  
Specimen Preparation ◽  
Solder Bumps ◽  
Low K ◽  
Underfill Material ◽  
Dic Technique

Since the introduction of Cu/low-k as the interconnect material, the chip-package interaction (CPI) has become a critical reliability challenge for flip chip packages. Revision of underfill material must be considered, which may compromise the life of flipchip interconnect by releasing the stresses transferred to the silicon devices from the solder bumps, and thereby maintain the overall package reliability. Thus, it is important to understand the thermo-mechanical behavior of solder bumps. In this study, the solder bump reliability in flip chip package was investigated through an experimental technique and numerical analysis. For the experimental assessment, thermo-mechanical behavior of solder joints, especially the solder bumps located at the chip corners where most failures usually occur was investigated. Digital Image Correlation (DIC) technique with optical microscope was utilized to quantify the deformation behavior and strains of a solder bump of flip-chip package subjected to thermal loading from 25°C to 100°C. As a specimen preparation for DIC technique, a flip-chip specimen was cross-sectioned before a manual polishing process followed by wet etching method in order to generate natural speckle patterns with high enough contrast on the measuring surface. Finally, finite element analysis (FEA) was conducted by simulating the thermal loading applied in the experiments, and validated with experimental results. Then, using the FEA analysis, parametric study for underfill material properties were performed on the reliability of flip chip package, by varying the glass transition temperature (Tg), Young’s modulus (E), and coefficient of thermal expansion (CTE). Averaged plastic work of the corner solder bump and stress at the die side were obtained and used as damage indicators for solder bumps and low-k dielectrics layer, respectively. The results show that high Tg, and E of underfill are generally desirable to improve the reliability of solder interconnects in the flip chip package.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

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