scholarly journals The Effects of Installation on the Elastic Stiffness Coefficients of Spudcan Foundations

2021 ◽  
Vol 9 (4) ◽  
pp. 429
Author(s):  
Wen-Long Lin ◽  
Zhen Wang ◽  
Fei Liu ◽  
Jiang-Tao Yi
Keyword(s):  
Small Strain ◽  
Elastic Stiffness ◽  
Stress Strain ◽  
Soft Clays ◽  
Strain Behavior ◽  
Installation Effects ◽  
Stiffness Coefficients ◽  
Strain Calculation ◽  
Dual Stage ◽  
Jack Up

Subjected to pre-load, spudcan foundations, widely utilized to support offshore jack-up rigs, may penetrate in a few diameters into soft clays before mobilizing sufficient resistance from soil. While its stress–strain behavior is known to be affected by the embedment condition and soil backflow, the small-strain calculation with wished-in-place assumption was previously adopted to analyze its elastic stiffness coefficients. This study takes advantage of a recently developed dual-stage Eulerian–Lagrangian (DSEL) technique to re-evaluate the elastic stiffness coefficients of spudcans after realistically modelling the deep, continuous spudcan penetration. A numerical parametric exercise is conducted to investigate the effects of strength non-homogeneity, embedment depths, and the spudcan’s size on the elastic stiffness. On these bases, an expression is provided such that the practicing engineers can conveniently factor the installation effects into the estimation of elastic stiffness coefficients of spudcans.

Nonlinear Behavior of Trabecular Bone at Small Strains

2000 ◽  
Vol 123 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Elise F. Morgan ◽  
Oscar C. Yeh ◽  
Wesley C. Chang ◽  
Tony M. Keaveny
Keyword(s):  
Trabecular Bone ◽  
Nonlinear Behavior ◽  
Strain Range ◽  
Small Strain ◽  
Tangent Modulus ◽  
Anatomic Site ◽  
Stress Strain ◽  
Strain Behavior ◽  
Loading Mode ◽  
Initial Modulus

Study of the behavior of trabecular bone at strains below 0.40 percent is of clinical and biomechanical importance. The goal of this work was to characterize, with respect to anatomic site, loading mode, and apparent density, the subtle concave downward stress–strain nonlinearity that has been observed recently for trabecular bone at these strains. Using protocols designed to minimize end-artifacts, 155 cylindrical cores from human vertebrae, proximal tibiae, proximal femora, and bovine proximal tibiae were mechanically tested to yield at 0.50 percent strain per second in tension or compression. The nonlinearity was quantified by the reduction in tangent modulus at 0.20 percent and 0.40 percent strain as compared to the initial modulus. For the pooled data, the mean±SD percentage reduction in tangent modulus at 0.20 percent strain was 9.07±3.24 percent in compression and 13.8±4.79 percent in tension. At 0.40 percent strain, these values were 23.5±5.71 and 35.7±7.10 percent, respectively. The magnitude of the nonlinearity depended on both anatomic site p<0.001 and loading mode p<0.001, and in tension was positively correlated with density. Calculated values of elastic modulus and yield properties depended on the strain range chosen to define modulus via a linear curve fit p<0.005. Mean percent differences in 0.20 percent offset yield strains were as large as 10.65 percent for some human sites. These results establish that trabecular bone exhibits nonlinearity at low strains, and that this behavior can confound intersite comparisons of mechanical properties. A nonlinear characterization of the small strain behavior of trabecular bone was introduced to characterize the initial stress–strain behavior more thoroughly.

Comparison of Tensile and Shear Behavior of Carbon-Black-Filled Elastomers

1987 ◽  
Vol 60 (4) ◽  
pp. 761-780 ◽  
Author(s):  
N. Nakajima ◽  
J. J. Scobbo ◽  
E. R. Harrell
Keyword(s):  
Carbon Black ◽  
Tensile Stress ◽  
High Speed ◽  
Complex Viscosity ◽  
Small Strain ◽  
Shear Behavior ◽  
Dynamic Shear ◽  
Stress Strain ◽  
Strain Behavior ◽  
Tensile Tester

Abstract Four NBR's and 2 SBR's with 40 phr carbon black and one SBR with 56 phr carbon black were characterized in both tensile stress-strain behavior and small-strain dynamic-shear behavior. The room temperature tensile stress-strain behavior was determined at strain rates of 0.00690, 0.0187, 0.0975, 0.0162, and 0.253 s−1. For dynamic-shear observations, loss and storage moduli were used to calculate the complex viscosity-frequency curve at small deformations and frequencies of 0.1 to 100 rad/s. Also, these data from tensile and shear experiments were compared with previous data from a capillary rheometer, high-speed tensile tester, and oscillatory tensile tester. Strain-time correspondence was found applicable to large-deformation tensile data up to the yield point. The formation of an anisotropic aggregate density in elongational deformation explains the higher viscosity and modulus for tensile behavior relative to small-strain shear behavior at similar conditions. In shear deformation and flow, the formation of an anisotropic density of aggregates does not seem to occur appreciably.

Stress Strain Behavior of Steel Fibre Based Concrete in Compression

2012 ◽  
Vol 1 (3) ◽  
pp. 32-38
Author(s):  
Tantary M.A ◽  
◽  
Upadhyay A ◽  
Prasad J ◽  
◽  
...  
Keyword(s):  
Steel Fibre ◽  
Stress Strain ◽  
Strain Behavior

scholarly journals Numerical analysis on zone-divided deep excavation in soft clays using a new small strain elasto–plastic constitutive model

2021 ◽  
Author(s):  
Afnan Younis Tanoli ◽  
Bin Yan ◽  
Yong-lin Xiong ◽  
Guan-lin Ye ◽  
Usama Khalid ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Constitutive Model ◽  
Small Strain ◽  
Deep Excavation ◽  
Soft Clays

scholarly journals Estimation of the Small-Strain Stiffness of Clean and Silty Sands using Stress-Strain Curves and CPT Cone Resistance

2009 ◽  
Vol 49 (4) ◽  
pp. 545-556 ◽  
Author(s):  
Junhwan Lee ◽  
Doohyun Kyung ◽  
Bumjoo Kim ◽  
Monica Prezzi
Keyword(s):  
Small Strain ◽  
Stress Strain ◽  
Cone Resistance ◽  
Small Strain Stiffness

Cord/Rubber Material Properties

1985 ◽  
Vol 58 (4) ◽  
pp. 830-856 ◽  
Author(s):  
R. J. Cembrola ◽  
T. J. Dudek
Keyword(s):  
Finite Element ◽  
Material Model ◽  
Rubber Composites ◽  
Stress Strain ◽  
Element Analysis ◽  
Rubber Layer ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Interlaminar Shear ◽  
Mechanics Of Composite Materials

Abstract Recent developments in nonlinear finite element methods (FEM) and mechanics of composite materials have made it possible to handle complex tire mechanics problems involving large deformations and moderate strains. The development of an accurate material model for cord/rubber composites is a necessary requirement for the application of these powerful finite element programs to practical problems but involves numerous complexities. Difficulties associated with the application of classical lamination theory to cord/rubber composites were reviewed. The complexity of the material characterization of cord/rubber composites by experimental means was also discussed. This complexity arises from the highly anisotropic properties of twisted cords and the nonlinear stress—strain behavior of the laminates. Micromechanics theories, which have been successfully applied to hard composites (i.e., graphite—epoxy) have been shown to be inadequate in predicting some of the properties of the calendered fabric ply material from the properties of the cord and rubber. Finite element models which include an interply rubber layer to account for the interlaminar shear have been shown to give a better representation of cord/rubber laminate behavior in tension and bending. The application of finite element analysis to more refined models of complex structures like tires, however, requires the development of a more realistic material model which would account for the nonlinear stress—strain properties of cord/rubber composites.

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