EXPERIMENTAL ANALYSIS ON THE MECHANICAL PROPERTIES OF SOIL-ROCK MIXED FILLERS WITH DIFFERENT ROCK CONTENTS ON A HIGH EMBANKMENT

10.6036/10235 ◽  
2021 ◽  
Vol 96 (5) ◽  
pp. 478-483
Author(s):  
YANQING ZHANG ◽  
HONGJUN JING ◽  
JUNYI DAI
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Volumetric Strain ◽  
Strain Curve ◽  
Mountainous Area ◽  
Stress Strain ◽  
Study Results ◽  
The Stability ◽  
Chang Model ◽  
Properties Of Soil

The mechanical properties of soil-rock mixed filler are the key factors influencing the high rockfill embankment stability. However, they remain unclear, given the complexity of soil-rock mixed filler structure. To analyze the stability of high rockfill embankment in the construction and operation phases, under the engineering background of a high rockfill embankment with a filling height of 50.6 m in the national highway 316 project within the Qinba mountainous area in China, a series of large-scale triaxial consolidated drained shear tests were performed on two soil-rock mixed fillers with 40% and 70% rock contents. Their stress-strain relation, deformation, and strength characteristics were observed. The applicability of Duncan-Chang model was also determined on the basis of the above tests. Results demonstrate that the stress-strain curve and volumetric strain of the filler with 40% rock content are strain hardening type and shear shrinkage type. The filler with 70% rock content has a weak strain softening, and its volumetric strain is first shear shrinkage and then shear dilation. The filler with 70% rock content has larger peak and critical frictional angles than the filler with 40% rock content. The tangential Poisson's ratios of the E-B and E-? models are obtained. The former can approximately reflect the volumetric strain characteristics of the filler with 40% rock content. The latter can approximately reflect those of the filler with 70% rock content. Yet, both models fail to describe the influence of confining pressure on the volumetric strain. The study results provide a reference for the stability analysis of high rockfill embankment engineering and provide parameters for constructing the constitutive model of soil-rock mixed fillers. Keywords: high embankment; soil-rock mixed filler; large-scale triaxial shear test; deformation characteristics; Duncan-Chang model

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

Advances in measuring mechanical properties of soil in relation to soil health

2021 ◽  
pp. 215-240
Author(s):  
Muhammad Naveed ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Soil Health ◽  
Indentation Test ◽  
Mechanical Tests ◽  
Confined Compression ◽  
Microstructural Stability ◽  
Rigorous Testing ◽  
The Stability ◽  
Properties Of Soil

Although mechanical properties of soil are fast and easy to measure, they have not been used as indicators of soil health apart from cone penetration resistance. The confined compression test is traditionally used for the prediction of soil compaction risks. Other mechanical tests such as soil rheometry, miniature indentation test, and tensile strength are used for assessing the impact of certain amendments on the stability of the soil. Rheological techniques are appropriate to investigate microstructural stability of soil on a particle-particle scale. Miniature indentation test is very useful to perform when mechanical properties of soil are required to measure at the mm scale. Measurement of the tensile strength of soil has an advantage as it eliminates the effect of water content. There is clearly a need for more practical and rigorous testing on comparing different mechanical properties of the soil to test how they perform relative to each other.

Mechanical properties of UN-5100 envelope material for stratospheric airship

2020 ◽  
pp. 1-17
Author(s):  
W.-c. Xie ◽  
X.-l. Wang ◽  
D.-p. Duan ◽  
J.-w. Tang ◽  
Y. Wei
Keyword(s):  
Mechanical Properties ◽  
Significant Role ◽  
Strain Curve ◽  
Image Correlation ◽  
Membrane Structures ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Biaxial Tensile ◽  
Envelope Material ◽  
Biaxial Tensile Testing

ABSTRACT Stratospheric airships are promising aircraft, usually designed as a non-rigid airship. As an essential part of the non-rigid airship, the envelope plays a significant role in maintaining its shape and bearing the external force load. Generally, the envelope material of a flexible airship consists of plain-weave fabric, composed of warp and weft fibre yarn. At present, biaxial tensile experiments are the primary method used to study the stress–strain characteristics of such flexible airship materials. In this work, biaxial tensile testing of UN-5100 material was carried out. The strain on the material under unusual stress and the stress ratio were obtained using Digital Image Correlation (DIC) technology. Also, the stress–strain curve was corrected by polynomial fitting. The slope of the stress–strain curve at different points, the Membrane Structures Association of Japan (MSAJ) standard and the Radial Basis Function (RBF) model were compared to identify the stress–strain characteristics of the materials. Some conclusions on the mechanical properties of the flexible airship material can be drawn and will play a significant role in the design of such envelopes.

scholarly journals Effect of Rock Particle Content on the Mechanical Behavior of a Soil-Rock Mixture (SRM) via Large-Scale Direct Shear Test

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Longqi Liu ◽  
Xuesong Mao ◽  
Yajun Xiao ◽  
Qian Wu ◽  
Ke Tang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Large Scale ◽  
Direct Shear Test ◽  
Shear Test ◽  
Volumetric Strain ◽  
Direct Shear ◽  
Stress Strain ◽  
Particle Content ◽  
Rock Particle

The mechanical strength of the landslide deposits directly affects the safety and operation of the roads in the western mountainous area of China. Therefore, the research is aimed at studying the mechanisms of a landslide deposit sample with different rock particle contents by analyzing its characteristics of the stress-strain behavior, the “jumping” phenomenon, the volumetric strain, and the shear strength parameters via a large-scale direct shear test. Stress-strain results show that stress-strain curves can be divided into 3 different stages: liner elastic stage, yielding stage, and strain-hardening stage. The shear strength of SRM behaves more like “soil” at a lower rock particle content and behaves more like “rock joints” at a higher rock particle content. Characteristics of the “jumping” phenomenon results show that the “intense jumping” stage becomes obvious with the increasing rock particle content and the normal stress. However, the lower the rock particle content is, the more obvious the “jumping” phenomenon under the same normal stress is. Volumetric strain results show that the sample with a lower rock particle content showed a dilatancy behavior under the low normal stress and shrinkage behavior under the high normal stress. The dilatancy value becomes smaller with the increasing normal stress. The maximum shear stress value of the rock particle content corresponds to the maximum value of dilatancy or shrinkage. We also conclude that the intercept of the Mohr failure envelope of the soil-rock mixture should be called the “equivalent cohesion,” not simply called the “cohesion.” The higher the normal stress and rock particle content are, the bigger the equivalent cohesion and the internal friction angle is.

Mechanical Properties and Stress-Strain Behaviour of Binary and Ternary Composites Based on Polyolefins and Vegetable Fillers

2017 ◽  
Vol 265 ◽  
pp. 221-226 ◽  
Author(s):  
E.E. Mastalygina ◽  
A.A. Popov
Keyword(s):  
Mechanical Properties ◽  
Filler Content ◽  
Low Density Polyethylene ◽  
Biological Degradation ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Composition And Structure ◽  
Study Results ◽  
Wide Range ◽  
Dimensional Parameters

Binary and ternary composites based on isotactic polypropylene and low-density polyethylene in a wide range of ratios without and with filler content have been investigated. Micron-scale vegetable cellulosic components initiating biological degradation have been used as fillers for polymeric composites. The analysis of stress-strain behaviour of the composites has shown a non-additive dependency of elongation and tensile strength at break on blends composition. Based on this study results the composition and structure of polymeric phase of binary and ternary composites, as well as dimensional parameters of filler particles have a significant impact on stress-strain behaviour of the materials. The main regularities determining materials mechanical properties have been discovered, that, in turn, could be used for predicting service behaviour of composites under investigation.

Experimental Research on the Stress - Strain Curve of Regional Confined Concrete under Single Axial Press

2014 ◽  
Vol 584-586 ◽  
pp. 1289-1292
Author(s):  
Guo Liang Zhu
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Constitutive Model ◽  
Theoretical Basis ◽  
Strain Curve ◽  
Confined Concrete ◽  
Constitutive Relationship ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Relationship Of

Regional confined concrete is base on confined concrete. It is the theory and application of a new attempt and development on confined concrete. To apply it to the actual project, we need to research mechanical properties and establish constitutive relationship of regional confined concrete. According to the research, we had carried on a series of tests, founded the stress-strain constitutive model of regional confined concrete under single axial press. The accuracy of theoretical analysis were more fully verified , and a theoretical basis for the application was provided.

scholarly journals Hybrid-modelling of Mechanical Properties and Thermo-mechanical Behaviour of Chopped Strand Mat Reinforced Thermoset Composites

2020 ◽  
pp. 1-14
Author(s):  
Cornelius Ogbodo Anayo Agbo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behaviour ◽  
Strain Curve ◽  
Fibre Volume ◽  
Secant Modulus ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hybrid Modelling ◽  
Thermoset Composites ◽  
Chopped Strand Mat

The concern of this paper is to develop simple workshop application models for predicting the mechanical properties and the evaluation of the thermo-mechanical behaviour of chopped strand fibre-mat reinforced thermoset composites. A hybrid of empirical and strength of materials approach was used at macro- and micro-mechanics levels to model the random fibres which were treated as simple bars within the mat preform and the resulting composite material. The model was validated experimentally by testing wet lay-up produced samples with varying fibre volume fractions and they were found to agree well. The toughness modulus of the composite was also modeled using the secant modulus obtained from the sample’s stress – strain curves of uniform material composites produced at different temperature histories. The toughness modulus determined using the new model was compared with that obtained using the area under the same stress – strain curve computed by Simpson’s rule and the results agreed very well.

scholarly journals Experimental and Theoretical Investigation on the Thermo-Mechanical Properties of Recycled Aggregate Concrete Containing Recycled Rubber

2021 ◽  
Vol 8 ◽  
Author(s):  
Yunchao Tang ◽  
Wanhui Feng ◽  
Zheng Chen ◽  
Yumei Nong ◽  
Minhui Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Microstructural Analysis ◽  
Strain Curve ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Recycled Rubber

The utilization of recycled aggregates made from construction wastes and recycled rubber made from waste tires is an effective method to realize the sustainable development. Thus, this study aims to determine the feasibility of using recycled aggregate concrete containing rubber, named rubberized recycled aggregate concrete (RRAC) as a new type of green-building material. The experimental carbon emissions test verified RRAC as a low-carbon material. In addition, the residual mechanical properties of RRAC were investigated under elevated temperatures. After exposure at 200, 400, and 600 C for 60 min, the stress−strain curve, compressive strength, energy absorption capacity, and spalling resistance of RRAC with recycled aggregate replacement ratios of 50 and 100%, rubber contents of 0, 5, 10, and 15% were explored with microstructural analysis. Moreover, empirical models were proposed to describe the effects of heated temperatures and rubber contents on the stress–strain relationship of RRAC. The results indicated that the rubber particles could reduce the spalling of specimens based on the vapor pressure theory. Therefore, this study provided scientific guidance for the design of structures made with RRAC for resisting high temperatures.

scholarly journals Study of the Use of Sawdust and Mycelium Composite as a Substitute of EPS

2021 ◽  
pp. 67-72
Author(s):  
R. Miralbes ◽  
D. Ranz ◽  
D. Zouzias
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Material Properties ◽  
Strain Curve ◽  
Expanded Polystyrene ◽  
Low Density ◽  
Stress Strain ◽  
Petroleum Origin ◽  
Small Grains ◽  
Substitute Material

AbstractExpanded polystyrene foams are a petroleum-origin material that is usually used in some applications such as motorcyclist helmets. Despite it notably mechanical properties, it low density and its capability to absorb energy during an impact, it is necessary to find a renewable-origin substitute material. Thus, it has been studied the use of a sawdust and mycelium composite material under quasi-static and dynamic efforts. Sawdust is a waste material that has very small grains that are totally disaggregated so it has very low material properties. The use of oyster mushroom mycelium generates an internal structure that joins grains and, consequently, the resultant material has notably high mechanical properties. Then it has been compared the resultant properties (stress-strain curve, absorbed energy, decelerations, etc.) with the different densities EPS ones and it has been concluded that this composite material, despite it high density, it could be a suitable substitute material and in some cases it has better properties.

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