Dynamic Compression Modulus of Elasticity in Open-Celled Polyethylene Foams.

The experimental diagrams between stress and strain components for soft soils are non-linear. Nonlinear diagrams qualitatively differ for soils of undisturbed and disturbed structures. It is believed that the manifestations of nonlinear properties of soil are associated with micro-destruction of soil structure under compression and, therefore, with changes in its mechanical characteristics under strain. It follows that the modulus of elasticity, Poisson’s ratio, viscosity and other mechanical parameters are the variables in the process of soil strain. Based on this, from the experimental results given in scientific literature, the changes in the modulus of elasticity and plasticity of soil are determined depending on the values of compression strain. In the process of static and dynamic compression of soil it is almost impossible to determine the boundaries of elastic and plastic strains in soft soil. So, the modulus under soil compression is called the strain modulus. From published results of experiments on dynamic and static compression of soil the most informative ones have been selected. Processing the selected compression diagrams of soft soil, the secant moduli of strain for loess soil and clay have been determined. It is established that the moduli of strain of clay and loess soil under static and dynamic strain vary depending on the rate of strain, the state of the structure and the level of compressive load.

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Elastic Modulus Calculation of GRT Fiber-Rubberized Haydite Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.450-451.423 ◽

2012 ◽

Vol 450-451 ◽

pp. 423-427

Author(s):

Bing Hua Xia ◽

Yuan Cai Liu ◽

Qing Wen Zhang

Keyword(s):

Compressive Strength ◽

Elastic Modulus ◽

Test Data ◽

Apparent Density ◽

Modulus Of Elasticity ◽

Compression Modulus ◽

Regression Method ◽

Orthogonal Test ◽

Intensity Level ◽

Static Compression

Experiment with intensity level for the LC30 ceramsite concrete as the research object, changing the content of cement, GRT fiber, rubber powder by the orthogonal test to configure GRT fiber—rubberized haydite concrete samples, maintenance samples 28d in standard conditions and respectively testing their modulus of elasticity、standard compressive strength and apparent density. Through the analysis of the test data, using regression method to establish the GRT fiber—rubberized haydite concrete static compression modulus of elasticity experiential formula and use new test data to compare the value of calculation. By comparing test values and calculated values proved availability of the regression formula.

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Evaluation of Thermal Endurance Characteristics of Micro-Cell Polyurethane Foams by Dynamic Compression Modulus

KOBUNSHI RONBUNSHU ◽

10.1295/koron.63.440 ◽

2006 ◽

Vol 63 (6) ◽

pp. 440-443 ◽

Cited By ~ 2

Author(s):

Hiromasa ADACHI

Keyword(s):

Dynamic Compression ◽

Compression Modulus ◽

Polyurethane Foams

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Density and shrinkage as guiding criteria for the optimization of the thermal conductivity of poly(urethane)-class aerogels

Journal of Sol-Gel Science and Technology ◽

10.1007/s10971-019-05161-6 ◽

2019 ◽

Vol 93 (1) ◽

pp. 149-167 ◽

Cited By ~ 1

Author(s):

Sylwia Członka ◽

Massimo F. Bertino ◽

Jan Kośny ◽

Nitin Shukla

Keyword(s):

Thermal Conductivity ◽

Physical Properties ◽

Dynamic Compression ◽

Monomer Concentration ◽

Volume Ratio ◽

Compression Modulus ◽

Toluene Diisocyanate ◽

Solubility Parameters ◽

K Index ◽

Freeze Dried

Abstract We investigated the effect of gelation solvent, monomer type, and monomer concentration on the physical properties of freeze-dried poly(urethane)-poly(isocyanurate) (PUR-PIR) aerogels, with particular emphasis on their thermal conductivity. It was found that the gelation solvent considerably affects aerogel morphology and physical properties. Aerogels with the lowest thermal conductivity were obtained using a mixture of tetrahydrofuran (THF) and acetonitrile, in a 50% volume ratio. The influence on thermal conductivity of polyol and isocyanate structure and of their concentration was also investigated. Rigid precursors, phloroglucinol (POL), and an aromatic polyisocyanate based on toluene diisocyanate (Desmodur RC) yielded the lowest thermal conductivity. Our results were compared with recent work reporting on parameters that could be used as predictors of thermal conductivity and other physical properties of organic aerogels. None of these parameters were found to be satisfactory predictors of aerogel properties. For example, no systematic correlation between solvent solubility parameters and aerogel properties was observed. We also examined the role of the K-index. This index, defined as the ratio between porosity and contact angle, was shown recently to be a good predictor of the properties of polyurea aerogels. While the thermal conductivity scaled with the K-index, the scaling was different for each of the isocyanate monomers considered in our experiments. Thermal conductivity, instead, scaled well with the product of density and shrinkage of aerogels, independent of monomer type. The reasons of this dependence on shrinkage and density are discussed, and the use of these parameters to guide experimentation on other systems is discussed. Physical properties such as static and dynamic compression modulus and thermal stability of the most promising formulations were also examined.

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Dynamic Compression Modulus of Expanded Polystyrene Foams.

KOBUNSHI RONBUNSHU ◽

10.1295/koron.57.757 ◽

2000 ◽

Vol 57 (11) ◽

pp. 757-759

Author(s):

Hiromasa ADACHI ◽

Teruo HASEGAWA

Keyword(s):

Dynamic Compression ◽

Compression Modulus ◽

Expanded Polystyrene

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Dynamic Compression Modulus of Close-Celled Polyethylene Foams.

KOBUNSHI RONBUNSHU ◽

10.1295/koron.58.56 ◽

2001 ◽

Vol 58 (1) ◽

pp. 56-58

Author(s):

Hiromasa ADACHI ◽

Teruo HASEGAWA

Keyword(s):

Dynamic Compression ◽

Compression Modulus

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Experimental Study on the Dynamic Modulus and Damping Ratio of Compacted Loess under Circular Dynamic Stress Paths

Advances in Civil Engineering ◽

10.1155/2021/9574548 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Liguo Yang ◽

Shengjun Shao ◽

Zhi Wang

Keyword(s):

Principal Stress ◽

Dynamic Stress ◽

Dynamic Compression ◽

Damping Ratio ◽

Stress Path ◽

Compression Modulus ◽

Dry Density ◽

Dynamic Shear Modulus ◽

Dynamic Shear ◽

Compacted Loess

Dynamic loads such as earthquakes and traffic will simultaneously generate vertical dynamic stress and horizontal shear stress in the foundation soil. When the vertical dynamic stress amplitude is twice the horizontal shear dynamic stress amplitude, and the phase difference between them is 90°, a circular dynamic stress path is formed in the τ z θ d ∼ σ zd − σ θ d / 2 stress coordinate system. To simulate the stress state of soil in the area of the circular dynamic stress path caused by bidirectional dynamic stress coupling, a series of tests of compacted loess under the action of a circular dynamic stress path were carried out using a hollow cylindrical torsion shear apparatus. The effects of the mean principal stress, dry density, and deviatoric stress ratio (the ratio of deviator stress to average principal stress) on the dynamic modulus and damping ratio of compacted loess were mainly studied. The test results show that, under the action of the circular dynamic stress path, the larger the mean principal stress is, the larger the dynamic compression modulus and dynamic shear modulus are. The dynamic compression modulus increases obviously with increasing dry density, but the dynamic shear modulus increases only slightly. When the deviator stress ratio increases from 0 to 0.4, the dynamic compression modulus and dynamic shear modulus increase to a certain extent. In addition, the greater the dry density and deviatoric stress ratio are, the greater the initial dynamic compression modulus and initial dynamic shear modulus of the compacted loess. The dynamic compression damping ratio of compacted loess increases with increasing mean principal stress, but the dynamic shear damping ratio decreases with increasing mean principal stress. Dry density basically has no effect on the dynamic compression damping ratio and dynamic shear damping ratio of compacted loess. When the dynamic strain exceeds 1%, the greater the deviatoric stress ratio is, the smaller the dynamic compression damping ratio and the dynamic shear damping ratio are. The research results can provide reference for the study of dynamic modulus and damping ratio of loess under special stress paths.

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