Texture Changes during Uniaxial Compression of Mg-3Al-1Zn

2004 ◽  
Vol 467-470 ◽  
pp. 429-434 ◽  
Author(s):  
Petra Backx ◽  
Matthew R. Barnett ◽  
Leo Kestens
Keyword(s):  
Uniaxial Compression ◽  
Annealing Treatment ◽  
Processing Parameters ◽  
Mechanical Anisotropy ◽  
Uniaxial Compression Test ◽  
Compression Tests ◽  
Texture Change ◽  
Different Temperatures ◽  
Axis Compression ◽  
Different Strains

The mechanical anisotropy of wrought Mg alloys is very high. For example the yield stress of extruded Mg-3Al-1Zn tested in tension can be as high as twice that obtained in compression [1]. To solve the problems this creates for product design it is necessary to understand the sensitivity of texture to processing parameters. Uniaxial compression tests at different temperatures were performed on cylindrical samples of an extruded Mg-3Al-1Zn bar. The texture during this deformation changes from a situation where all crystal c-axes are nearly perpendicular to the sample axis to one where the c-axes are all nearly parallel to this axis. Compression was stopped at different strains to examine the rate of this texture change. Textures were examined using EBSD measurements. It was found that different mechanisms operate depending on the temperature of deformation and that a variety of textures can be created. Also it was seen that an annealing treatment performed after compression has an influence on the texture. Afterwards the samples were subjected to another uniaxial compression test to examine the influence of texture on room temperature properties.

scholarly journals Study on Relaxation Damage Properties of High Viscosity Asphalt Sand under Uniaxial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yazhen Sun ◽  
Zhangyi Gu ◽  
Jinchang Wang ◽  
Chenze Fang ◽  
Xuezhong Yuan
Keyword(s):  
Uniaxial Compression ◽  
Viscoelastic Model ◽  
Relaxation Modulus ◽  
Maxwell Model ◽  
High Viscosity ◽  
Secondary Development ◽  
Compression Tests ◽  
Crack Control ◽  
Different Temperatures ◽  
Damage Process

Laboratory investigations of relaxation damage properties of high viscosity asphalt sand (HVAS) by uniaxial compression tests and modified generalized Maxwell model (GMM) to simulate viscoelastic characteristics coupling damage were carried out. A series of uniaxial compression relaxation tests were performed on HVAS specimens at different temperatures, loading rates, and constant levels of input strain. The results of the tests show that the peak point of relaxation modulus is highly influenced by the loading rate in the first half of an L-shaped curve, while the relaxation modulus is almost constant in the second half of the curve. It is suggested that for the HVAS relaxation tests, the temperature should be no less than −15°C. The GMM is used to determine the viscoelastic responses, the Weibull distribution function is used to characterize the damage of the HVAS and its evolution, and the modified GMM is a coupling of the two models. In this paper, the modified GMM is implemented through a secondary development with the USDFLD subroutine to analyze the relaxation damage process and improve the linear viscoelastic model in ABAQUS. Results show that the numerical method of coupling damage provides a better approximation of the test curve over almost the whole range. The results also show that the USDFLD subroutine can effectively predict the relaxation damage process of HVAS and can provide a theoretical support for crack control of asphalt pavements.

scholarly journals Application of supervised machine learning as a method for identifying DEM contact law parameters

2021 ◽  
Vol 18 (6) ◽  
pp. 7490-7505
Author(s):  
Piotr Klejment ◽  
Keyword(s):  
Machine Learning ◽  
Uniaxial Compression ◽  
Calibration Procedure ◽  
Supervised Machine Learning ◽  
Critical Threshold ◽  
Uniaxial Compression Test ◽  
Universal Relation ◽  
Compression Tests ◽  
Input Parameters ◽  
Pertinent Question

<abstract> <p>Calibration of Discrete Element Method (DEM) models is an iterative process of adjusting input parameters such that the macroscopic results of simulations and experiments are similar. Therefore, selecting appropriate input parameters of a model effectively is crucial for the efficient use of the method. Despite the growing popularity of DEM, there is still an ongoing need for an efficient method for identifying contact law parameters. Commonly used trial and error procedures are very time-consuming and unpractical, especially in the case of models with many parameters to calibrate. It seems that machine learning may offer a new approach to that problem. This research aims to apply supervised machine learning to figure out the dependencies between specific microscopic and macroscopic parameters. More than 6000 DEM simulations of uniaxial compression tests gathered the data for two algorithms - Multiple Linear Regression and Random Forest. Promising results with an accuracy of over 99% give good hope for finding a universal relation between input and output parameters (for a specific DEM implementation) and reducing the number of simulations required for the calibration procedure. Another pertinent question concerns the size of the DEM models used during calibration based on the uniaxial compression test. It has been proven that calibration of certain parameters can be done on smaller samples, where the critical threshold is around 30% of the radius of the original model.</p> </abstract>

scholarly journals The Determination of a Damage Model for Mudstone under Uniaxial Loading in Acidic Conditions

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
K. Cao ◽  
L. Ma ◽  
Y. Wu ◽  
A. J. S. (Sam) Spearing ◽  
Naseer Muhammad Khan ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Mechanical Test ◽  
Damage Parameter ◽  
Coal Bed ◽  
Relative Mass ◽  
Uniaxial Compression Test ◽  
Peak Strain ◽  
Compression Tests ◽  
Analysis And Design ◽  
Chemical Damage

The influence of acid solutions was investigated on the mechanical properties of mudstone. Uniaxial compression tests on mudstone samples were conducted to determine the variations of relative mass, porosity, deformation, and strength characteristics of mudstone subjected to acidic solutions with different pH values. The change of pH, relative mass, and porosity of mudstone in the process of acid solution immersion was monitored during soaking. The mechanism of hydrochemical corrosion of mudstone samples was preliminarily discussed. The damage parameter was introduced based on the porosity rate. The results show that with increased solution acidity, the peak stress and elastic modulus decreased to different levels, while the peak strain increases in the rock samples. The increased chemical damage parameters reduce the mechanical parameters and increased the deformation parameters. On the basis of the mechanical test, considering the stress-strain relationship of rock in the compaction stage, a segmented damage constitutive model of rock based on chemical damage parameters is established, and the test results are verified. The results show that the correlation coefficient between the theoretical curve and the experimental data is as high as 0.98, and the model is suitable for the analysis of chemically corroded rock under the uniaxial compression test. The results provide a reference for the analysis and design of coal-bed methane wells where the rocks frequently become acidic during the production of methane.

Microstructure, Texture and Mechanical Properties of Mg-0.8 Zn-0.3 Gd-0.5 Ca Alloy Sheets

2016 ◽  
Vol 852 ◽  
pp. 171-175
Author(s):  
Cheng Bin Wei ◽  
Hong Yan ◽  
Cai Chen ◽  
Xing Hao Du ◽  
Rong Shi Chen
Keyword(s):  
Mechanical Properties ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Mechanical Anisotropy ◽  
Double Peaks ◽  
Intermetallic Particles ◽  
Coarse Grains ◽  
Different Temperatures ◽  
Basal Pole ◽  
Change Of Microstructure

In this study, the microstructure, texture and mechanical properties of rolled Mg-0.8 Zn-0.3 Gd-0.5 Ca sheets have been investigated. It is shown that the as-cast microstructure of the Mg-0.8 Zn-0.3 Gd-0.5 Ca alloy is composed of coarse grains with fine intermetallic particles. The deformed microstructure of the as-rolled sheets results in the non-basal texture with triple peaks. Upon annealing treatment at different temperatures, the fraction of recrystallized microstructure is increased and the grains grow up. With the increase of annealing temperature, the (0002) basal pole of as-rolled sheets has transformed into texture with double peaks firstly and then into triple peaks. Accompanying the change of microstructure and texture, structure and mechanical anisotropy of the rolled sheets is modified.

scholarly journals Energy Analysis Method for Uniaxial Compression Test of Sandstone under Static and Quasi-Dynamic Loading Rates

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhixi Liu ◽  
Guangming Zhao ◽  
Xiangrui Meng ◽  
Ruofei Zhang ◽  
Dong Chunliang ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Elastic Energy ◽  
Loading Rate ◽  
Uniaxial Compression Test ◽  
Input Energy ◽  
Analysis Method ◽  
Compression Tests ◽  
Loading Rates

To investigate the energy evolution characteristics of sandstone under static-quasi-dynamic loading rates (1.0 × 10−3, 5.0 × 10−3, 1.0 × 10−2, 5.0 × 10−2, and 1.0 × 10−1 mm/s), the uniaxial compression tests, the uniaxial cyclic loading-unloading tests, and the uniaxial incrementally cyclic loading-unloading tests were conducted under five different loading rates. Through analysis of the elastic energy of the uniaxial cyclic loading-unloading test and the uniaxial incremental cyclic loading-unloading test, show that the impact of the loading rate and the cycle numbers on the elastic energy is less. Hence, we can deem that when the loads of the uniaxial incremental cyclic loading-unloading test and the uniaxial compression test are equal, the elastic energy of the two also equals. The energy in the uniaxial compression tests analyzed by the uniaxial incrementally cyclic loading-unloading test show that elastic energy increased linearly when the input energy increased under different loading rates. Through the linear energy storage law and the uniaxial incremental cyclic loading and unloading test, it is possible to analyze the energy in the uniaxial compression test at any loading rates. The results show that the greater the loading rate, the greater the peak elastic energy and peak input energy. But when the load is equal, the greater the loading rate, the smaller the input energy and elastic energy. Compared with traditional methods, the new energy analysis method is accurate and simple. Meanwhile, based on energy dissipation, the damage of rock during uniaxial compression tests was studied.

scholarly journals Comparison of Proctor and Uniaxial Compression Tests for Selected Soils

2018 ◽  
Vol 22 (1) ◽  
pp. 5-13
Author(s):  
Dariusz Błażejczak ◽  
Kinga Śnieg ◽  
Małgorzata Słowik
Keyword(s):  
Uniaxial Compression ◽  
Compression Test ◽  
Humus Content ◽  
Solid Particles ◽  
Dry Density ◽  
Uniaxial Compression Test ◽  
Compression Tests ◽  
Lateral Expansion ◽  
Soil Material ◽  
Uniaxial Test

AbstractThe objective of this paper was to compare the results of soil material compaction carried out with the use of the Proctor and uniaxial compression tests in order to find relations between these methods. Soil material in the form of loose mass was collected from the layer deposited at the depth from 35 to 60 cm in order to determine its typical properties (textural group, density of solid particles, humus content, reaction, plastic and liquid limits) and in order to compact it in the Proctor apparatus and in the uniaxial compression test. Results of both tests were used for construction of regression models reflecting the course of the unit stress (Pρdp), necessary to generate compaction equal to the dry density of solid particles obtained in the Proctor apparatus (ρdp) in relation to the sample moisture (ws). It was stated that the stress value Pρdp on the soil sample in the uniaxial compression test depends significantly on ws. It was proved that for the purpose of comparing the results of both tests, the uniaxial stress of samples must be performed in conditions of their lateral expansion. It was also proved that the use of the uniaxial test with possible lateral expansion of soil with a model sample, a diameter of which is 100 and the height is 30 mm, one may determine the obtained compaction with the use of the plate movement value.

Influence of Loading Rate on Uniaxial Compression Test of Rock Specimen with Random Joints

2011 ◽  
Vol 396-398 ◽  
pp. 217-220
Author(s):  
Bing Xie ◽  
Jin Jun Guo ◽  
Xiang Xia
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compression ◽  
Uniaxial Compressive Strength ◽  
Compression Test ◽  
Rock Specimen ◽  
Loading Rate ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Uniaxial Compression Test ◽  
Compression Tests

Numerical specimens with ramdom joints is established by particle flow code PFC2D and uniaxial compression tests are conducted under three different loading rate. Studies have shown that strength of uniaxial compression are all increased with the loading rate no matter what specimen is complete or with random joints. The sensitivity of changes of uniaxial compressive strength of specimen with random joints decreases with increasing of the loading rate.

scholarly journals Identification of changes in mechanical properties of sandstone subjected to high temperature: meso-and micro-scale testing and analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Adrian Różański ◽  
Anna Różańska ◽  
Maciej Sobótka ◽  
Michał Pachnicz ◽  
Mirosława Bukowska
Keyword(s):  
Uniaxial Compression ◽  
Temperature Treatment ◽  
Uniaxial Compression Test ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Micro Computed Tomography ◽  
Micro Scale ◽  
Investigative Techniques ◽  
Comparison Of The Results

AbstractMaterial properties largely depend on their structure, and are strongly dependent on the scale of observation. Under the influence of various processes, the structure of a material can undergo evolution, which leads to major changes in the mechanical parameters and morphology of the medium. To understand the behaviour of a given material exposed to the influence of various factors, e.g. loading and temperature treatment, and to be able to modify it appropriately, it is crucial to recognize its structure both in the scale of engineering applications and at the micro-scale. The article proposes a procedure for assessing changes in the structure of sandstone exposed to the temperature treatment. The presented procedure allows the morphology of the material to be evaluated and the influence of temperature treatment on mechanical parameters of rocks to be analysed, by combining use of different laboratory techniques. The changes in rock material have been characterized using three investigative techniques, i.e. a uniaxial compression test, nanoindentation and micro-computed tomography. The uniaxial compression tests were carried out for 11 different temperature values in the range of 23–1000 °C, which enabled the determination of the change in uniaxial compressive strength and Young’s modulus of the sandstone as a function of temperature. Micro-scale laboratory tests were utilised to identify changes in the mechanical and morphological parameters of the sandstone exposed to the temperature of 1000 °C. The results were referred to those obtained for the reference samples, i.e. not subjected to heating (T = 23 °C). Comparison of the results showed an evident relation between the microstructure changes and the mesoscopic properties.

scholarly journals The influence of microstructure geometry on the scale effect in mechanical behaviour of heterogeneous materials

2017 ◽  
Vol 24 (4) ◽  
pp. 557-571 ◽  
Author(s):  
Adrian Różański ◽  
Magdalena Rajczakowska ◽  
Andrzej Serwicki
Keyword(s):  
Uniaxial Compression ◽  
Scale Effect ◽  
Mechanical Behaviour ◽  
Young Modulus ◽  
Uniaxial Compression Test ◽  
Compression Tests ◽  
Number Of Factors ◽  
Pore Size Distributions ◽  
Attenuation Profiles ◽  
The Relationship

AbstractThere are a significant number of factors which have impact on the scale effect in the mechanical behaviour of composite materials. In this paper, the influence of the microstructure on this phenomenon is examined. In particular, how the results of the uniaxial compression test are affected by the microstructure geometry is verified. For the purposes of this study, two different materials are chosen, i.e. pure gypsum and mortar. Firstly, the microstructures of the two considered materials are compared with the use of different microstructure measures, i.e. attenuation profiles, porosity and pore size distributions, calculated based on the images obtained from the X-ray microCT. Then, a series of uniaxial compression tests is performed for a large number of cylindrical specimens made of the two materials under study. Four different sample diameters are assumed in order to investigate the size effect in the considered composites. For both materials, the results of uniaxial compressive strength and the Young modulus are presented. The relationship between the microstructure of the material and the scale effect in mechanical properties is proved. The scale effect is more demonstrable in the case of the material which exhibits a more heterogeneous microstructure.

Numerical Study on Uniaxial Compression Test of Rock Specimen with Random Holes

2011 ◽  
Vol 418-420 ◽  
pp. 848-850
Author(s):  
Bing Xie ◽  
Li Guo ◽  
Xiang Xia
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compression ◽  
Uniaxial Compressive Strength ◽  
Compression Test ◽  
Rock Specimen ◽  
Numerical Study ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Uniaxial Compression Test ◽  
Compression Tests

Numerical specimens with ramdom holes is established by particle flow code PFC2D and uniaxial compression tests are conducted. Studies have shown that the uniaxial compressive strength of the specimen accelerated decline while the porosity increasing uniformly. With the increasing of the porosity，the plastic of the specimen increases.

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