scholarly journals CHARACTERIZATION OF CROSS-ANISOTROPIC SOIL DEPOSITS FROM ISOTROPIC COMPRESSION TESTS

2005 ◽  
Vol 45 (5) ◽  
pp. 89-102 ◽  
Author(s):  
POUL V. LADE ◽  
ANDREI V. ABELEV
Keyword(s):  
Compression Tests ◽  
Isotropic Compression ◽  
Soil Deposits ◽  
Anisotropic Soil

scholarly journals Design and characterization of concrete masonry parts and structural concrete using repurposed plastics as aggregate

2019 ◽  
Vol 28 (1) ◽  
pp. 81-88
Author(s):  
Miguel A. González-Montijo ◽  
Hildélix Soto-Toro ◽  
Cristian Rivera-Pérez ◽  
Silvia Esteves-Klomsingh ◽  
Oscar Marcelo Suárez
Keyword(s):  
Structural Strength ◽  
Construction Materials ◽  
Tensile Tests ◽  
Compression Tests ◽  
Conventional Concrete ◽  
Structural Capacity ◽  
Plastic Type ◽  
Concrete Mix ◽  
Scientists And Engineers

AbstractHistorically known for being one of the major pollutants in the world, the construction industry, always in constant advancement and development, is currently evolving towards more environmentally friendly technologies and methods. Scientists and engineers seek to develop and implement green alternatives to conventional construction materials. One of these alternatives is to introduce an abundant, hard to recycle, material that could serve as a partial aggregate replacement in masonry bricks or even in a more conventional concrete mixture. The present work studied the use of 3 different types of repurposed plastics with different constitutions and particle size distribution. Accordingly, several brick and concrete mix designs were developed to determine the practicality of using these plastics as partial aggregate replacements. After establishing proper working material ratios for each brick and concrete mix, compression tests as well as tensile tests for the concrete mixes helped determine the structural capacity of both applications. Presented results proved that structural strength can indeed be reached in a masonry unit, using up to a 43% in volume of plastic. Furthermore, a workable structural strength for concrete can be achieved at fourteen days of curing, using up to a 50% aggregate replacement. A straightforward cost assessment for brick production was produced as well as various empirical observations and recommendations concerning the feasibility of each repurposed plastic type examined.

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.

Measurement of the Material State Including the Effects of Recovery and Recrystallization

2000 ◽  
Author(s):  
M. E. Bange ◽  
A. J. Beaudoin ◽  
M. G. Stout ◽  
S. R. MacEwen
Keyword(s):  
Elevated Temperatures ◽  
High Strain ◽  
Quantitative Measure ◽  
Experimental Program ◽  
Strain Rates ◽  
Compression Tests ◽  
State Variable ◽  
Mechanical Threshold ◽  
Material State

Abstract Deformation at elevated temperatures in combination with high strain rates leads to recovery and recrystallization in aluminum alloys. Previous work in recrystallization has emphasized the detailing of microstructural trend in progression from the deformed to the annealed state. In the following, we examine the effect of rate dependence on deformation on AA 5182 and AA 6061. It is demonstrated that identification of underlying microstructural mechanisms is critical. An experimental program is then outlined for characterization of recovery and recrystallization of AA 5182. Instantaneous hardening rate and flow stress are developed from interrupted compression tests. These data are used to establish a quantitative measure of recovery through evaluation of a state variable for work hardening, the mechanical threshold. It is intended that the results serve as a foundation for development of relations for evolution of a mechanical state variable in the presence of recrystallization. Such a framework is necessary for the practical prediction of interstand recrystallization in hot rolling operations.

Experimental-Numerical Characterization of Ordinary Concrete at the Meso-Scale

2021 ◽  
Author(s):  
GIANLUCA MAZZUCCO ◽  
Beatrice Pomaro ◽  
Giovanna Xotta ◽  
Enrico Garbin ◽  
Valentina Salomoni ◽  
...  
Keyword(s):  
Yield Criterion ◽  
Plain Concrete ◽  
Point Of View ◽  
Good Prediction ◽  
Deformation Capacity ◽  
Compression Tests ◽  
Fe Method ◽  
Stress States ◽  
Meso Scale

Modeling the post-peak behaviour of brittle materials like concrete is still a challenge from the point of view of computational mechanics, due to the strong nonlinearities arising in the material behaviour during softening and the complexity of the yield criterion that may describe their deformation capacity in generic triaxial stress states. A numerical model for plain concrete in compression is formulated within the framework of the coupled elasto-plastic-damage theory. The aim is to simulate via the Finite Element (FE) method the stress-strain behaviour of concrete at the meso-scale, where local confinement effects generally characterize the cement paste under the action of the surrounding aggregates. The mechanical characterization of the components are accomplished through a specific experimental campaign. With the subsequent validation study, it is shown that a few calibration parameters give a good prediction of load strength and deformation capacity coming from real uniaxial compression tests.

scholarly journals Fabrication and Characterization of Scaffolds of Poly(ε-caprolactone)/Biosilicate® Biocomposites Prepared by Generative Manufacturing Process

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Daniel Aparecido Lopes Vieira da Cunha ◽  
Paulo Inforçatti Neto ◽  
Kelli Cristina Micocci ◽  
Caroline Faria Bellani ◽  
Heloisa Sobreiro Selistre-de-Araujo ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Manufacturing Process ◽  
Potential Application ◽  
Morphological Characterization ◽  
Mechanical Compression ◽  
Compression Tests ◽  
Extrusion Head ◽  
Fabrication And Characterization

Scaffolds of poly(ε-caprolactone) (PCL) and their biocomposites with 0, 1, 3, and 5 wt.% Biosilicate® were fabricated by the generative manufacturing process coupled with a vertical miniscrew extrusion head to application for restoration of bone tissue. Their morphological characterization indicated the designed 0°/90° architecture range of pore sizes and their interconnectivity is feasible for tissue engineering applications. Mechanical compression tests revealed an up to 57% increase in the stiffness of the scaffold structures with the addition of 1 to 5 wt.% Biosilicate® to the biocomposite. No toxicity was detected in the scaffolds tested by in vitro cell viability with MC3T3-E1 preosteoblast cell line. The results highlighted the potential application of scaffolds fabricated with poly(ε-caprolactone)/Biosilicate® to tissue engineering.

Thermal effects on yielding and wetting-induced collapse of recompacted and intact loess

2018 ◽  
Vol 55 (8) ◽  
pp. 1095-1103 ◽  
Author(s):  
C.W.W. Ng ◽  
Q. Cheng ◽  
C. Zhou
Keyword(s):  
Yield Stress ◽  
Applied Stress ◽  
Thermal Effects ◽  
Normal Force ◽  
Compression Tests ◽  
Isotropic Compression ◽  
Single Temperature ◽  
Higher Temperature ◽  
Unsaturated Loess ◽  
Intact Loess

Yielding and wetting-induced collapse are two important interrelated aspects of unsaturated loess behaviour. Previous studies on loess were generally conducted under a single temperature condition. The principal objective of this study is to investigate thermal effects on yielding and wetting-induced collapse of recompacted and intact loess. Isotropic compression tests were carried out to determine yield stress at different suctions (0 and 100 kPa) and temperatures (5, 23, and 50 °C). Moreover, wetting tests were conducted at various temperatures and stresses. Results of the wetting tests were interpreted using the measured yield stress at various suctions and temperatures. It is found that yield stress decreases with decreasing suction (wetting-induced softening). The wetting-induced softening of recompacted loess is more significant at a higher temperature. The observed thermal effects on wetting-induced softening are likely because with decreasing suction, the stabilizing interparticle normal force decreases more at a higher temperature. In contrast, when the applied stress reaches the yield stress during wetting, yielding and plastic volumetric contraction can be observed. More importantly, wetting-induced contraction of recompacted loess at 50 °C is about three times of that at 5 °C. The larger contraction at 50 °C is mainly because the wetting-induced softening is larger at a higher temperature.

STUDY ON MECHANICAL CHARACTERIZATION OF LIVER TISSUE BASED ON HAPTIC DEVICES FOR VIRTUAL SURGICAL SIMULATION

2016 ◽  
Vol 16 (08) ◽  
pp. 1640016 ◽  
Author(s):  
JING YANG ◽  
LINGTAO YU ◽  
LAN WANG ◽  
HONGYANG LI ◽  
QI AN
Keyword(s):  
Soft Tissue ◽  
Constitutive Equation ◽  
Soft Tissues ◽  
Mechanical Characterization ◽  
Surgical Simulation ◽  
Surgical Instruments ◽  
Compression Tests ◽  
Haptic Devices ◽  
Liver Tissues

In recent years, virtual surgical simulation has been one of the hot direction of digital medical research, it is mainly used in teaching, training, diagnosis, preoperative planning, rehabilitation and modeling and analysis of surgical instruments. The modeling of soft tissue of human organs is the basis to realize the virtual surgical simulation. The quasi-linear viscoelastic (QLV) theory has been proposed by Fung, and it was widely used for modeling the constitutive equation of soft tissues. The purpose of this study is to determine the mechanical characterization of the liver soft tissue based on the PHANTOM Omni Haptic devices. Five parameters are included in the constitutive equation with QLV theory, which must be determined experimentally. The specimens were obtained from fresh porcine liver tissues in vitro. The liver tissues were cut into 14[Formula: see text]mm[Formula: see text][Formula: see text][Formula: see text]14[Formula: see text]mm[Formula: see text][Formula: see text][Formula: see text]14[Formula: see text]mm cubes. Two types of unconfined compression tests were performed on cube liver specimens. Puncture tests were performed on the complete liver. The material parameters of the QLV constitutive equation were obtained by fitting the experimental data. These parameters will provide the references for the computational modeling of the liver in the virtual surgical simulation.

An experimental approach to the thermomechanical characterization of a NiTiCu shape memory alloy using strain gauges

2016 ◽  
Vol 231 (1-2) ◽  
pp. 113-121
Author(s):  
Albert Fabregat-Sanjuan ◽  
Francesc Ferrando Piera ◽  
Silvia De la Flor López
Keyword(s):  
Shape Memory Alloy ◽  
Shear Modulus ◽  
Shape Memory ◽  
Twist Angle ◽  
Strain Tensor ◽  
Strain Ratio ◽  
Strain Gauges ◽  
Compression Tests ◽  
Thermal Chamber

In this work, a characterization of a NiTiCu (Ti44.6Ni5Cu (at.%)) shape memory alloy (tube specimens) has been done via tension, compression and torsion tests conditions. Torsion tests were done in a special homemade equipment, which is based on an instrumented dividing head with a specifically designed thermal chamber. This configuration is able to measure torque and twist angle with isothermal tests at different temperatures as well as to apply thermal cycles with a fixed twist angle. Moreover, tube specimens were instrumented with stacked strain gauges rosettes in order to obtain the strain tensor. Strain gauges were also used to calibrate the equipment and to identify the real stress state in torsion tests. The results have shown differences between the shear modulus measured on torsion tests and the shear modulus calculated from the measurements at tension and compression tests due to the tension/compression asymmetry and a non-constant strain ratio value. Thermal cycling tests at different values of fixed twist angles not only have led to characterize the evolution of torque as a function of the temperature but also to understand the different interacting mechanisms in torsion tests.

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