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 >

Ting Huang, Xin Zhuo^*

Journal of Renewable Materials, Vol.10, No.4, pp. 993-1005, 2022, DOI:10.32604/jrm.2022.017373

Abstract The construction of grouting butt joints of bamboo tubes is simple and efficient. However, when the joint is bent, the low tensile strength of the mortar easily leads to cracking of the mortar prior to the failure of the bamboo tube. In this paper, a comparative test of the bending capacity was performed on grouting butt joints reinforced by nonperforated, fully perforated, and semiperforated steel plates embedded in bamboo tubes to obtain the load-displacement curves and ultimate bearing capacity of various specimens. The strengthening effect of CFRP pasted on bamboo tubes was also studied. The results show that the opening… More > Graphic Abstract

Datao Xu¹, Zhenghui Lu¹, Siqin Shen², Gusztáv Fekete², Ukadike C. Ugbolue³, Yaodong Gu^1,*

Molecular & Cellular Biomechanics, Vol.18, No.2, pp. 107-118, 2021, DOI:10.32604/mcb.2021.015453

Abstract Patellar tendinopathy is a clinical symptom of patellar tendons characterized by local pain in the front of the knee joint. It is common among basketball and volleyball players. Patients with patellar tendinopathy may exhibit different landing strategies during landing compared to healthy individuals. The purpose of this study was to compare the differences in lower limb joint energy dissipation (eccentric work) values for the symptomatic patellar tendinopathy (PT) athletes and no patellar tendinopathy (UPT) athletes during single-leg landing. A total of 26 (PT: 13, UPT:13) semi-professional male basketball and volleyball player’s kinetic data were collected during the landing phases. Joint… More >

Boqing Li, Xiaolong Bai, Yongli Zhu^*

Molecular & Cellular Biomechanics, Vol.18, No.2, pp. 99-105, 2021, DOI:10.32604/mcb.2021.014748

Abstract In the process of swimming, the shoulder joint will be damaged when the arm is stroking. To reduce the injury of shoulder joints and improve the speed of stroke, it is necessary to train the flexibility of shoulder joints. This paper briefly introduced the concept of shoulder joint and flexibility and then explained the traditional stretching training method and proprioceptive neuromuscular facilitation (PNF) stretching method. Then, taking 20 college team swimmers of Yunnan University as the subjects, the comparative experiment of the traditional and PNF stretching methods was carried out. The results showed that the shoulder rotation index of the… More >

Hongmin Li^1,*, Hongxing Qiu², Wenbo Wang³

Journal of Renewable Materials, Vol.9, No.6, pp. 1111-1125, 2021, DOI:10.32604/jrm.2021.014722

Abstract The mortise-tenon joint is an important hub transmitting and distributing external loads for load-bearing components (beams, columns et al.) in the ancient-timber frame structure system. However, the conventional steel hoop reinforcement methods often insert wood screws into the timber components. When the reinforced joint rotates greatly, the anchoring failure of the screws will cause damage to the timber joint. To solve this problem, this study proposes a detachable and replaceable non-destructive flat-steel jacket reinforcement method in which horizontal flat steel is placed in the center of the joint, and the bolt is extended to the outside of the timber beam.… More >

Daobing Wang¹, Fang Shi^2,*, Hao Qin^1,*, Dongliang Sun¹, Bo Yu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 891-914, 2021, DOI:10.32604/cmes.2021.014206

Abstract In this study, we use the extended finite element method (XFEM) with a consideration of junction enrichment functions to investigate the mechanics of hydraulic fractures related to naturally cemented fractures. In the proposed numerical model, the lubrication equation is adopted to describe the fluid flow within fractures. The fluid-solid coupling systems of the hydraulic fracturing problem are solved using the Newton-Raphson method. The energy release rate criterion is used to determine the cross/arrest behavior between a hydraulic fracture (HF) and a cemented natural fracture (NF). The failure patterns and mechanisms of crack propagation at the intersection of natural fractures are… More >

Yinhuan Yang^1,*, Manfeng Gong¹, Xiaoqun Xia¹, Yuling Tang²

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1239-1249, 2021, DOI:10.32604/cmes.2021.014129

Abstract In order to study the mechanical properties of Z-pins reinforced laminated composite single-lap adhesively bonded joint under un-directional static tensile load, damage failure analysis of the joint was carried out by means of test and numerical simulation. The failure mode and mechanism of the joint were analyzed by tensile failure experiments. According to the experimental results, the joint exhibits mixed failure, and the ultimate failure is Z-pins pulling out of the adherend. In order to study the failure mechanism of the joint, the finite element method is used to predict the failure strength. The numerical results are in good agreement… More >

Meijuan Shan^{1, 2}, Libin Zhao^{2, *}, Wei Huang³, Fengrui Liu², Jianyu Zhang^{4, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 101-127, 2020, DOI:10.32604/cmes.2020.09099

Abstract The high demands for load-carrying capability and structural efficiency of composite-metal bolted joints trigger in-depth investigations on failure mechanisms of the joints in hygrothermal environments. However, few studies have been presented to exhaustively reveal hygrothermal effects on the failure of CFRP-metal bolted joints, which differ from CFRP-CFRP or metal-metal bolted joints because of the remarkably different material properties of CFRPs and metals. In this paper, hygrothermal effects on tensile failures of single-lap and double-lap CFRP-aluminum bolted joints were experimentally and numerically investigated. A novel numerical model, in which a hygrothermal-included progressive damage model of composites was established and elastic-plastic models… More >

Fengrui Liu^{1, 2, 3}, Wanting Yao^{1, 2}, Xinhong Shi^{4, *}, Libin Zhao^{1, 2}, Jianyu Zhang^{5, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 977-999, 2020, DOI:10.32604/cmc.2020.07184

Abstract To minimize the mass and increase the bearing failure load of composite doublelap bolted joints, a three-step optimization strategy including feasible region reduction, optimization model decoupling and optimization was presented. In feasible region reduction, the dimensions of the feasible design region were reduced by selecting dominant design variables from numerous multilevel parameters by sensitivity analyses, and the feasible regions of variables were reduced by influence mechanism analyses. In model decoupling, the optimization model with a large number of variables was divided into various sub-models with fewer variables by variance analysis. In the third step, the optimization sub-models were solved one… More >

Vincenzo Gulizzi^1,2, Piervincenzo Rizzo^2,3, Alberto Milazzo⁴

Structural Durability & Health Monitoring, Vol.10, No.1, pp. 19-54, 2014, DOI:10.3970/sdhm.2014.010.019

Abstract The electromechanical impedance (EMI) method is one of the many nondestructive evaluation approaches proposed for the health monitoring of aerospace, civil, and mechanical structures. The method consists of attaching or embedding one or more wafer-type piezoelectric transducers (PZTs) to the system of interest, the host structure, and measuring certain electrical characteristics of the transducers. As these characteristics are also related to the impedance of the host structure, they can be used to infer the mechanical properties of the monitored structure. In the study presented in this paper, we utilize the EMI to monitor the quality of adhesively bonded joints. A… More >