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  • Open Access

    ARTICLE

    Mental Health Impacts of Information and Communication Technology Usage in South Africa

    Akinboade Oludele Akinloye1,*, Obareng Baldwin Manoko2, Mmafani Serote2, Trevor Taft3

    International Journal of Mental Health Promotion, Vol.23, No.2, pp. 255-276, 2021, DOI:10.32604/IJMHP.2021.011111

    Abstract This study examined mental health issues affecting the group of individuals who are in the social media contact list of the researchers. This was done by administering a closed structured questionnaire, covering information from participants’ demographic characteristics, duration of time spent on ICT usage, to their perceived health effects thereof. Male respondents, largely unemployed are active ICT users, addicted to the Internet, and also suffer from unspecified ailments. Aged 31–35 and above, half of men and all women participants spend more than 5 h per day. High-intensive ICT use is associated, in general, with concurrent symptoms of information overload, depression… More >

  • Open Access

    ARTICLE

    Fatigue Crack Propagation Analysis of Orthotropic Steel Bridge with Crack Tip Elastoplastic Consideration

    Ying Wang1,*, Zheng Yan1, Zhen Wang2

    CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.2, pp. 549-574, 2021, DOI:10.32604/cmes.2021.014727

    Abstract Due to the complex structure and dense weld of the orthotropic steel bridge deck (OSBD), fatigue cracks are prone to occur in the typical welding details. Welding residual stress (WRS) will cause a plastic zone at the crack tip. In this paper, an elastoplastic constitutive model based on the Chaboche kinematic hardening model was introduced, and the extended finite element method (XFEM) was used to study the influence of material elastoplasticity and crack tip plastic zone on the law of fatigue crack propagation. By judging the stress state of the residual stress field at the crack tip and selecting different… More >

  • Open Access

    ARTICLE

    Experimental Study of Effect of Temperature Variations on the Impedance Signature of PZT Sensors for Fatigue Crack Detection

    Saqlain Abbas1,2,*, Fucai Li1, Zulkarnain Abbas3,4, Taufeeq Ur Rehman Abbasi5, Xiaotong Tu6, Riffat Asim Pasha7

    Sound & Vibration, Vol.55, No.1, pp. 1-18, 2021, DOI:10.32604/sv.2021.013754

    Abstract Structural health monitoring (SHM) is recognized as an efficient tool to interpret the reliability of a wide variety of infrastructures. To identify the structural abnormality by utilizing the electromechanical coupling property of piezoelectric transducers, the electromechanical impedance (EMI) approach is preferred. However, in real-time SHM applications, the monitored structure is exposed to several varying environmental and operating conditions (EOCs). The previous study has recognized the temperature variations as one of the serious EOCs that affect the optimal performance of the damage inspection process. In this framework, an experimental setup is developed in current research to identify the presence of fatigue… More >

  • Open Access

    ARTICLE

    Damping Analysis and Failure Mechanism of 3D Printed Bio-Based Sandwich with Auxetic Core under Bending Fatigue Loading

    Khawla Essassi1,2,*, Jean-Luc Rebiere1, Abderrahim El Mahi1, Mohamed Amine Ben Souf2, Anas Bouguecha2, Mohamed Haddar2

    Journal of Renewable Materials, Vol.9, No.3, pp. 569-584, 2021, DOI:10.32604/jrm.2021.012253

    Abstract Meta-sandwich composites with three-dimensional (3D) printed architecture structure are characterized by their high ability to absorb energy. In this paper, static and fatigue 3-point bending tests are implemented on a 3D printed sandwich composites with a re-entrant honeycomb core. The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid with flax fiber reinforcement. Experimental tests are performed in order to evaluate the durability and the ability of this material to dissipate energy. First, static tests are conducted to study the bending behaviour of the sandwich beams, as well as to determine the failure… More >

  • Open Access

    ARTICLE

    The Effects of Different Post-Heat Treatments on Rolling Contact Fatigue Behaviors of Direct Laser Cladding Inconel 625 Coatings

    Qiaoxin Zhang1,2, Rui Chen1, Ding Jin2, Chen Zhou2,*, Xuewu Li3,4,5,*

    Journal of Renewable Materials, Vol.9, No.1, pp. 129-144, 2021, DOI:10.32604/jrm.2021.011596

    Abstract In this paper, the microstructures and rolling contact fatigue behaviors of laser cladding Inconel 625 coatings with or without post-heat treatments were analyzed. The results revealed that the fatigue resistance of the laser cladding coating after any post-heat treatment was worse than that of the as-deposited coating. First, through the finite element analysis, the distribution of stress along the thickness direction of the coating was obtained, and it was concluded that the bonding interface between the coating and the matrix had little effect on the fatigue properties of the coating. Then X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy… More >

  • Open Access

    ARTICLE

    The Effect of Surface Pit Treatment on Fretting Fatigue Crack Initiation

    Qingming Deng1,2, Xiaochun Yin1, Magd Abdel Wahab3,4,*

    CMC-Computers, Materials & Continua, Vol.66, No.1, pp. 659-673, 2021, DOI:10.32604/cmc.2020.012878

    Abstract This paper analyses the effect of surface treatment on fretting fatigue specimen by numerical simulations using Finite Element Analysis. The processed specimen refers to artificially adding a cylindrical pit to its contact surface. Then, the contact radius between the pad and the specimen is controlled by adjusting the radius of the pit. The stress distribution and slip amplitude of the contact surface under different contact geometries are compared. The critical plane approach is used to predict the crack initiation life and to evaluate the effect of processed specimen on its fretting fatigue performance. Both crack initiation life and angle can… More >

  • Open Access

    ARTICLE

    Numerical Simulation of Bone Remodeling Coupling the Damage Repair Process in Human Proximal Femur

    Chuanyong Qu*, Hui Yuan

    CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.2, pp. 829-847, 2020, DOI:10.32604/cmes.2020.012407

    Abstract Microdamage is produced in bone tissue under the long-term effects of physiological loading, as well as age, disease and other factors. Bone remodeling can repair microdamage, otherwise this damage will undermine bone quality and even lead to fractures. In this paper, the damage variable was introduced into the remodeling algorithm. The new remodeling algorithm contains a quadratic term that can simulate reduction in bone density after large numbers of loading cycles. The model was applied in conjunction with the 3D finite element method (FEM) to the remodeling of the proximal femur. The results showed that the initial accumulation of fatigue… More >

  • Open Access

    ARTICLE

    Fatigue Performance Evaluation for Welded Details in Orthotropic Steel Deck Bridges Using Multi-Scale Finite Element Method

    Rongfeng Chen1, Changqing Miao2,*

    Structural Durability & Health Monitoring, Vol.14, No.3, pp. 205-228, 2020, DOI:10.32604/sdhm.2020.08997

    Abstract In order to study the fatigue properties of rib-to-deck welded connection and rib-to-rib welded connection in orthotropic steel bridge decks, a multi-scale finite element model was set up to analyze the stress distribution characteristics and the load test was conducted on the Taizhou Yangtze River Bridge. Comparing the vehicle test results with the multi-scale finite element model results to verify the accuracy of the finite element simulation for the stress response of two welded details. The results indicated that: The stress at the rib-to-deck welded connection and the rib-to-rib welded connection are the bending stress and the membrane stress, respectively;… More >

  • Open Access

    ARTICLE

    Probabilistic Life Calculation Method of NdFeB Based on Brittle Fatigue Damage Model

    Lei Li, Guolai Yang*, Jiahao Li

    CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.3, pp. 865-884, 2020, DOI:10.32604/cmes.2020.010720

    Abstract This paper proposes a probabilistic life calculation method of NdFeB based on brittle fatigue damage model. Firstly, Zhu-Wang-Tang (ZWT) constitutive model considering strain rate is established, and based on this, a numerical co-simulation model for NdFeB life calculation is constructed. The life distribution diagram of NdFeB under different stress levels is obtained after simulation. Secondly, a new model of brittle fatigue damage based on brittle damage mechanism is proposed. Then the parameters in the model are identified according to the life distribution diagram of NdFeB and the parameter distribution of the damage evolution model when applied to NdFeB is obtained.… More >

  • Open Access

    ARTICLE

    Water Pressure Variation Properties Research in Non-ballasted Track Crack Interior under Fatigue Loading

    Xu Gui-Hong1, Zhang Wei-Biao2, Liao Hua-Rong1, Yang Rong-Shan3

    Intelligent Automation & Soft Computing, Vol.25, No.4, pp. 735-743, 2019, DOI:10.31209/2019.100000077

    Abstract This paper reports the experimental study of water pressure properties inside crack of Non-ballasted track structure. Pre-existing crack concrete specimens with 510 × 1290 × 80mm dimensions were produced, and fluid-fracture interaction tests under cyclic loading were performed. The water pressure were measured at different locations inside cracks and with different loading frequencies as well as amplitudes. By using the experimental data, then is employed to investigate the water pressure distribution inside cracks affected by both the frequency and amplitude under cyclic loading. From this study, it was determined that the water pressure of cracks alternates between positive and negative… More >

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