scholarly journals Theoretical Calculation Method for the Hugoniot Elastic Limit of Hard Rock Based on Ideal Elastoplastic Model

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yihao Cheng ◽  
Chunming Song ◽  
Yizhong Tan ◽  
Songlin Yue ◽  
Gan Li ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
Calculation Method ◽  
Poisson’S Ratio ◽  
Hard Rock ◽  
Strength Criterion ◽  
Poisson's Ratio ◽  
Dominant Factor ◽  
Plastic Limit ◽  
Plate Impact ◽  
Impact Experiments

To study the theoretical calculation method of the HEL for hard rock, the major factors determining the strength of rock under dynamic loadings are firstly discussed. Secondly, the calculation method of the HEL of hard rock is suggested based on the Lundborg strength criterion, and the parameters influencing the HEL are analyzed and discussed. Thirdly, the HEL obtained by theoretical calculation, numerical modeling, and experiments are compared. Fourthly, the abnormal decreasing or increasing of the HEL in plate impact experiments of hard rock is explained. This research shows that the HEL increases with Poisson’s ratio, the shear strength at zero pressure, the coefficient of internal friction and the plastic limit, and Poisson’s ratio and the plastic limit could be the most important factors. The simplified model of this work can give a rational and practical prediction of the HEL of hard rock in theory, and the complicated interaction between the “damage front” and the diffuse elastic precursor is assumed to explain two special effects of the HEL in plate impact experiments of hard rock, where Poisson’s ratio related to damage levels seems to be the dominant factor.

Advances in Test Methods for Poisson’s Ratio of Solid Propellant

2014 ◽  
Vol 998-999 ◽  
pp. 397-400
Author(s):  
Xiao Zhang ◽  
Jian Zheng ◽  
Wei Peng ◽  
Zhi Xu Gu
Keyword(s):  
Viscoelastic Material ◽  
Calculation Method ◽  
Poisson’S Ratio ◽  
Solid Propellant ◽  
Test Methods ◽  
Poisson's Ratio ◽  
Foreign Study

This paper reviews domestic and foreign study result of the calculation method and variation of solid propellant and other viscoelastic material ratio of solid propellant, the viscoelastic material's Poisson's ratio as well as Poisson's ratio's influence on the structure performance of solid propellant.

scholarly journals An Extension Failure Criterion for Brittle Rock

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Aizhong Lu ◽  
Ning Zhang ◽  
Guisen Zeng
Keyword(s):  
Principal Stress ◽  
Poisson’S Ratio ◽  
Compressive Strain ◽  
Strength Criterion ◽  
Maximum Principal Stress ◽  
Intermediate Principal Stress ◽  
Brittle Rock ◽  
Poisson's Ratio ◽  
Triaxial Tests ◽  
True Triaxial

Under the triaxial compressive state, the compressive strain is supposed to happen in the direction of the maximum principal stress, but tensile strain happens in the direction of the minimum principal stress. Moreover, as the intermediate principal stress is not too high, the corresponding strain can also be tensile. If the brittle rock is assumed as linear elastic in the prefailure stage, a new strength criterion based on the sum of the two tensile strains was presented. The new criterion considers the differences in mechanical parameters (i.e., elastic modulus and Poisson’s ratio) under tension and compression. The parameters of the criterion only include Poisson’s ratio and uniaxial strength. And the effect of the intermediate principal stress σ 2 can be reflected. Certain featured failure phenomenon of rock material can be explained well by the proposed criterion. The results of conventional and true triaxial tests can verify the criterion well. Finally, the criterion is compared with the Mohr–Coulomb and Drucker–Prager criteria.

The Model for Calculating Elastic Modulus and Poisson's Ratio of Coal Body

2013 ◽  
Vol 6 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ai Chi ◽  
Li Yuwei
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Fractured Rock ◽  
Rock Block ◽  
Poisson's Ratio ◽  
Linear Elastic ◽  
Study Results ◽  
The Face ◽  
Block Face ◽  
Coal Rock

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent cracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat. By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and butt cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially increased and then decreased with increasing of the face cleat inclination.

scholarly journals A Hybrid Artificial Intelligence Model to Predict the Elastic Behavior of Sandstone Rocks

2019 ◽  
Vol 11 (19) ◽  
pp. 5283 ◽  
Author(s):  
Gowida ◽  
Moussa ◽  
Elkatatny ◽  
Ali
Keyword(s):  
Poisson’S Ratio ◽  
Accurate Determination ◽  
Oil And Gas Industry ◽  
Poisson's Ratio ◽  
Elastic Behavior ◽  
Percentage Error ◽  
Ann Model ◽  
Field Development ◽  
Well Completion

Rock mechanical properties play a key role in the optimization process of engineering practices in the oil and gas industry so that better field development decisions can be made. Estimation of these properties is central in well placement, drilling programs, and well completion design. The elastic behavior of rocks can be studied by determining two main parameters: Young’s modulus and Poisson’s ratio. Accurate determination of the Poisson’s ratio helps to estimate the in-situ horizontal stresses and in turn, avoid many critical problems which interrupt drilling operations, such as pipe sticking and wellbore instability issues. Accurate Poisson’s ratio values can be experimentally determined using retrieved core samples under simulated in-situ downhole conditions. However, this technique is time-consuming and economically ineffective, requiring the development of a more effective technique. This study has developed a new generalized model to estimate static Poisson’s ratio values of sandstone rocks using a supervised artificial neural network (ANN). The developed ANN model uses well log data such as bulk density and sonic log as the input parameters to target static Poisson’s ratio values as outputs. Subsequently, the developed ANN model was transformed into a more practical and easier to use white-box mode using an ANN-based empirical equation. Core data (692 data points) and their corresponding petrophysical data were used to train and test the ANN model. The self-adaptive differential evolution (SADE) algorithm was used to fine-tune the parameters of the ANN model to obtain the most accurate results in terms of the highest correlation coefficient (R) and the lowest mean absolute percentage error (MAPE). The results obtained from the optimized ANN model show an excellent agreement with the laboratory measured static Poisson’s ratio, confirming the high accuracy of the developed model. A comparison of the developed ANN-based empirical correlation with the previously developed approaches demonstrates the superiority of the developed correlation in predicting static Poisson’s ratio values with the highest R and the lowest MAPE. The developed correlation performs in a manner far superior to other approaches when validated against unseen field data. The developed ANN-based mathematical model can be used as a robust tool to estimate static Poisson’s ratio without the need to run the ANN model.

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