Saixuan Chen¹, Jie Yang^1,*, Guohua Cui¹, Fuzhou Niu², Baiqiang Yao¹, Yu Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 2021-2039, 2023, DOI:10.32604/cmes.2022.022669

Abstract This paper proposes a zero-moment control torque compensation technique. After compensating the gravity and friction of the robot, it must overcome a small inertial force to move in compliance with the external force. The principle of torque balance was used to realise the zero-moment dragging and teaching function of the lightweight collaborative robot. The robot parameter identification based on the least square method was used to accurately identify the robot torque sensitivity and friction parameters. When the robot joint rotates at a low speed, it can approximately satisfy the torque balance equation. The experiment uses the joint position and the… More >

Shrikant Arunrao Thote^*, Netra Pal Singh

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 501-511, 2023, DOI:10.32604/fdmp.2022.021502

Abstract The thermal behavior of pipes with a twisted tape inside (used to enhance heat transfer through the tube wall) is studied in the laminar flow regime. Oil is used as the work fluid with the corresponding Reynolds Number spanning the interval 200–2000. It is found that in such conditions the ‘Nusselt Number’ (Nu) gradually increases with reducing the tape twist ratio, whereas the friction factor is detrimentally affected by the presence of the tape (as witnessed by the comparison with the companion case where a plain tube is considered). In particular, it is shown that the heat transfer efficiency can… More >

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 >

Rida Tazi¹, Adil Echchelh¹, Mohammed El Ganaoui², Aouatif Saad^3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1631-1638, 2022, DOI:10.32604/fdmp.2022.021975

Abstract Unlike most fluids, granular materials include coexisting solid, liquid or gaseous regions, which produce a rich variety of complex flows. Dense flows of grains driven by gravity down inclines occur in nature and in industrialprocesses. To describe the granular flow on an inclined surface, several studies were carried out. We can cite in particular the description of Saint-Venant which considers a dry granular flow, without cohesion and it only takes into account the substance-substrate friction, this model proposes a simplified form of the granular flow, which depends on the one side on the angle of inclination of the substrate with… More >

T. Khatir^1,2, M. Bouchetara², K. Derrar², M. Djafri³, S. Khatir⁴, M. Abdel Wahab^5,6,*

CMC-Computers, Materials & Continua, Vol.72, No.2, pp. 2259-2273, 2022, DOI:10.32604/cmc.2022.020879

Abstract Braking efficiency is characterized by reduced braking time and distance, and therefore passenger safety depends on the design of the braking system. During the braking of a vehicle, the braking system must dissipate the kinetic energy by transforming it into heat energy. A too high temperature can lead to an almost total loss of braking efficiency. An excessive rise in brake temperature can also cause surface cracks extending to the outside edge of the drum friction surface. Heat transfer and temperature gradient, not to forget the vehicle's travel environment (high speed, heavy load, and steeply sloping road conditions), must thus… More >

Kailei Wang, Mingjing Li^*, Peng Yan, Leiting Dong^*

CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.1, pp. 165-197, 2022, DOI:10.32604/cmes.2022.019188

Abstract The main goal of this work is to study the ballistic performance of multi-layered moderately-thick metallic targets. Several target configurations have been considered in this work, with various types of interlayer connection (spaced, contacted and adhesive) and the number of layers (four and eight), and the influence of target configurations on ballistic performance has been studied experimentally and numerically. In the experiments, the targets were impacted by 12.7-mm projectiles at a velocity around 820 m/s. The experimental results show that, with similar total thickness, the contacted and adhesive targets exhibit better ballistic performance than the monolithic targets, and the four-layered targets… More >

Izzat Al-Darraji^1,2, Ayad A. Kakei², Ayad Ghany Ismaeel³, Georgios Tsaramirsis⁴, Fazal Qudus Khan⁵, Princy Randhawa⁶, Muath Alrammal⁴, Sadeeq Jan^7,*

CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 1011-1024, 2022, DOI:10.32604/cmc.2022.022451

Abstract Robotic manipulators are widely used in applications that require fast and precise motion. Such devices, however, are prompt to nonlinear control issues due to the flexibility in joints and the friction in the motors within the dynamics of their rigid part. To address these issues, the Linear Matrix Inequalities (LMIs) and Parallel Distributed Compensation (PDC) approaches are implemented in the Takagy–Sugeno Fuzzy Model (T-SFM). We propose the following methodology; initially, the state space equations of the nonlinear manipulator model are derived. Next, a Takagy–Sugeno Fuzzy Model (T-SFM) technique is used for linearizing the state space equations of the nonlinear manipulator.… More >

Qingfang Lv¹, Tongchen Han¹, Ye Liu^2,*, Yi Ding¹, Yujie Lu¹

Journal of Renewable Materials, Vol.9, No.10, pp. 1757-1779, 2021, DOI:10.32604/jrm.2021.015536

Abstract

Cross-laminated bamboo (CLB) have a high strength to weight ratio and stable bidirectional mechanical properties. Inspired by the investigation on cross-laminated timber (CLT) rocking walls, CLB rocking walls with conventional friction dampers (CFDs) are studied in this paper. To investigate the mechanical properties of the CLB rocking wall, seven tests are conducted under a cyclic loading scheme, and different test parameters, including the existence of the CFDs, the moment ratio, and the loading times, are discussed. The test results show a bilinear behavior of the CLB rocking wall. The small residual displacements of the CLB rocking wall demonstrate an idealized… More > Graphic Abstract

Adnan¹, Umar Khan², Naveed Ahmed³, Syed Tauseef Mohyud-Din⁴, Ilyas Khan^5,*, El-Sayed M. Sherif^6,7

CMC-Computers, Materials & Continua, Vol.67, No.1, pp. 477-489, 2021, DOI:10.32604/cmc.2021.012739

Abstract The investigation of local thermal transport rate in the nanolubricants is significant. These lubricants are broadly used in environmental pollution, mechanical engineering and in the paint industry due to high thermal performance rate. Therefore, thermal transport in ZnO-SAE50 nanolubricant under the impacts of heat generation/absorption is conducted. The colloidal suspension is flowing between parallel stretching disks in which the lower disk is positioned at z = 0 and upper disk apart from distance d. The problem is transformed in dimensionless version via described similarity transforms. In the next stage, an analytical technique (VPM) is implemented for the solution purpose. The… More >

Shichao Ma^{1, 2, *}, Xin Ning^{1, 2, *}, Liang Wang³

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.1, pp. 49-59, 2020, DOI:10.32604/cmes.2020.06911

Abstract Friction systems are a kind of typical non-linear dynamical systems in the actual engineering and often generate abundant dynamics phenomena. Because of non-smooth characteristics, it is difficult to handle these systems by conventional analysis methods directly. At the same time, random perturbation often affects friction systems and makes these systems more complicated. In this context, we investigate the steady-state stochastic responses and stochastic P-bifurcation of friction systems under random excitations in this paper. And in order to retain the non-smooth of friction system, the generalized cell mapping (GCM) method is first used to the original stochastic friction systems without any… More >