Weiliang Gao¹, Shixu Jia², Tingting Zhao^2,3,*, Zhiyong Wang²

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 3495-3511, 2024, DOI:10.32604/cmes.2023.046188

Abstract The mechanical properties of interfacial transition zones (ITZs) have traditionally been simplified by reducing the stiffness of cement in previous simulation methods. A novel approach based on the discrete element method (DEM) has been developed for modeling concrete. This new approach efficiently simulates the meso-structure of ITZs, accurately capturing their heterogeneous properties. Validation against established uniaxial compression experiments confirms the precision of this model. The proposed model can model the process of damage evolution containing cracks initiation, propagation and penetration. Under increasing loads, cracks within ITZs progressively accumulate, culminating in macroscopic fractures that traverse the mortar matrix, forming the complex,… More >

Sen Zhang¹, Jie Jiang^2,3,*, Yuedong Wang⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.5, pp. 1159-1172, 2023, DOI:10.32604/fdmp.2022.024070

Abstract To improve the application of discrete element models (DEM) to the design of agricultural crushers, in this study a new highly accurate model is elaborated. The model takes into account the fiber structure, porous nature of the material and the leaf sheath coating structure. Dedicated experimental tests are conducted to determine the required “intrinsic” and basic contact parameters of the considered banana straw materials. A large number of bonding parameters are examined in relation to the particle aggregation model in order to characterize different actual banana straws. Using the particle surface energy contact model, the viscosity characteristics of the crushed… More > Graphic Abstract

Shuai Wang, Zhihong Yu^*, Wenjie Zhang, Dongxu Zhao, Aorigele

Phyton-International Journal of Experimental Botany, Vol.91, No.11, pp. 2559-2582, 2022, DOI:10.32604/phyton.2022.021354

Abstract

Sunflower (Helianthus annuus L.) is one of the four major oil crops in the world and has high economic value. However, the lack of discrete element method (DEM) models and parameters for sunflower seeds hinders the application of DEM for computer simulation in the key working processes of sunflower seed sowing and harvesting. The present study was conducted on two varieties of sunflower, and the DEM model of sunflower seeds was established by using 3D scanning technology based on the distribution of triaxial dimensions and volumes of the geometric model of sunflower seeds. Similarly, the physical characteristics parameters of sunflower… More >

Tongming Qu¹, Shaocheng Di², Y. T. Feng^1,3,*, Min Wang⁴, Tingting Zhao³, Mengqi Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.1, pp. 129-144, 2021, DOI:10.32604/cmes.2021.016172

Abstract This study presents an AI-based constitutive modelling framework wherein the prediction model directly learns from triaxial testing data by combining discrete element modelling (DEM) and deep learning. A constitutive learning strategy is proposed based on the generally accepted frame-indifference assumption in constructing material constitutive models. The low-dimensional principal stress-strain sequence pairs, measured from discrete element modelling of triaxial testing, are used to train recurrent neural networks, and then the predicted principal stress sequence is augmented to other high-dimensional or general stress tensor via coordinate transformation. Through detailed hyperparameter investigations, it is found that long short-term memory (LSTM) and gated recurrent… More >

Tingting Zhao¹, Y. T. Feng^2,*, Jie Zhang¹, Zhihua Wang¹, Zhiyong Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.2, pp. 721-735, 2021, DOI:10.32604/cmes.2021.015913

Abstract This paper presents a convex polyhedral based discrete element method for modelling the dynamic behaviour of rockfills for resisting high speed projectile penetration. The contact between two convex polyhedra is defined by the Minkowski overlap and determined by the GJK and EPA algorithm. The contact force is calculated by a Minkowski overlap based normal model. The rotational motion of polyhedral particles is solved by employing a quaternion based orientation representation scheme. The energy-conserving nature of the polyhedral DEM method ensures a robust and effective modelling of convex particle systems. The method is applied to simulate the dynamic behaviour of a… More >

Yuanchao Zhang¹, Zhiyuan Xia^2,*, Yujing Jiang¹, Miao Chen³, Jiankang Liu¹, Qian Yin⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.1, pp. 259-280, 2020, DOI:10.32604/cmes.2020.011076

Abstract Hole-like defects are very common in natural rock or coal mass, and play an important role in the failure and mechanical behaviors of rock or coal mass. In this research, multi-holed coal specimens are constructed numerically and calibrated based on UDEC-GBM models. Then, the strength, deformation and failure behavior of the porous specimens are analyzed, with consideration of hole density (P) and confining pressure (σ₃). The simulation results are highly consistent with those available experiment results, and show that the compressive strength decreases exponentially with the increasing hole density. The strength loss is mainly caused by the reduction of cohesion… More >

Rui Chen^{1, 2}, Yong Wang^{1, 2}, Ruitao Peng^{1, 2, *}, Shengqiang Jiang^{1, 2}, Congfang Hu^{1, 2}, Ziheng Zhao^{1, 2}

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 717-737, 2020, DOI:10.32604/cmes.2020.07438

Abstract An inverse method for parameters identification of discrete element model combined with experiment is proposed. The inverse problem of parameter identification is transmitted to solve an optimization problem by minimizing the distance between the numerical calculations and experiment responses. In this method, the discrete element method is employed as numerical calculator for the forward problem. Then, the orthogonal experiment design with range analysis was used to carry out parameters sensitivity analysis. In addition, to improve the computational efficiency, the approximate model technique is used to replace the actual computational model. The intergeneration projection genetic algorithm (IP-GA) is employed as the… More >