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Static Analysis of Functionally Graded Sandwich Plates Using an Efficient and Simple Refined Theory

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Chinese Journal of Aeronautics 2011年第4期24卷 432-433页

作者： Hadj Henni ABDELAZIZ Hassen Ait ATMANE ismail mechab Lakhdar BOUMIA Abdelouahed TOUNSI Adda Bedia El ABBAS Laboratoire des Matériaux et Hydrologie Université de Sidi Bel Abbes Département de Génie Civil Université Ibn Khaldoun Département de Génie Civil Faculté de Génie Civil et d'Architecture Univesité de Chlef Département de Physique Université de Sidi Bel Abbes

In this paper, a new displacement based high-order shear deformation theory is introduced for the static response of functionally graded sandwich plate. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory presented is variationally consistent, has strong similarity with classical plate theory in many aspects, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Two common types of functionally graded sandwich plates, namely, the sandwich with fimctionally graded facesheet and homogeneous core and the sandwich with homogeneous facesheet and functionally graded core, are considered. Governing equations are derived from the principle of virtual displacements. The closed-form solution of a simply supported rectangular plate subjected to sinu- soidal loading has been obtained by using the Navier method. The validity of the present theory is investigated by comparing some of the present results with those of the classical, the first-order and the other higher-order theories. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded sandwich plates.

关键词： functionally graded materials sandwich plates refined plate theory bending Navier solution

ANN-based empirical modelling of pile behaviour under static compressive loading

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 594-608页

作者： Abdussamad ismail Department of Civil Engineering Bayero UniversityKanoNigeria

Artificial neural networks have been widely used over the past two decades to successfully develop empirical models for a variety of geotechnical problems. In this paper, an empirical model based on the product-unit neural network (PUNN) is developed to predict the load-deformation behaviour of piles based SPT values of the supporting soil. Other parameters used as inputs include particle grading, pile geometry, method of installation as well as the elastic modulus of the pile material. The model is trained using full-scale pile loading tests data retrieved from FHWA deep foundations database. From the results obtained, it is observed that the proposed model gives a better simulation of pile load-deformation curves compared to the Fleming’s hyperbolic model and t-z approach.

关键词： piles in compression load-deformation behaviour product-unit neural network

Estimating moment capacity of ferrocement members using self-evolving network

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Frontiers of Structural and Civil Engineering 2019年第4期13卷 926-936页

作者： Abdussamad ismail Department of Civil Engineering Bayero University Kano Kano State PMB 3011 Nigeria

In this paper, an empirical model based on self-evolving neural network is proposed for predicting the flexural behavior of ferrocement elements. The model is meant to serve as a simple but reliable tool for estimating the moment capacity of ferrocement members. The proposed model is trained and validated using experimental data obtained from the literature. The data consists of information regarding flexural tests on ferrocement specimens which include moment capacity and cross-sectional dimensions of specimens, concrete cube compressive strength, tensile strength and volume fraction of wire mesh. Comparisons of predictions of the proposed models with experimental data indicated that the models are capable of accurately estimating the moment capacity of ferrocement members. The proposed models also make better predictions compared to methods such as the plastic analysis method and the mechanism approach. Further comparisons with other data mining techniques including the back-propagation network, the adaptive spline, and the Kriging regression models indicated that the proposed models are superior in terms prediction accuracy despite being much simpler models. The performance of the proposed models was also found to be comparable to the GEP-based surrogate model.

关键词： ferrocement moment capacity self-evolving neural network

Numerical and Experimental Study of the Impact of Key Parameters on a PVT Air Collector:Mass Flow Rate and Duct Depth

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Journal of Thermal Science 2021年第5期30卷 1625-1642页

作者： ismail BAKLOUTI Zied DRISS National School of Engineers of Monastir University of Monastir5019MonastirTunisia Laboratory of Electromechanical Systems(LASEM) National School of Engineers of SfaxUniversity of Sfax3038SfaxTunisia

The PVT-air solar system simultaneously generates electrical and thermal ***,increasing the cost-effectiveness of the system requires an appropriate choice of key parameters such as mass flow rate and air channel *** this paper,a PVT-air kit of a single module with a 30°slope was used to measure photovoltaic electricity and air heating power in the city of Sfax,***,a computer method was implemented using the ANSYS Fluent 17.0 software and the MATLAB program to analyse the properties of the airflow and to characterise PVT-air yields under different mass flow rates and *** the comparison of numerical and experimental data,the numerical method was validated with a good ***,we have found that increasing of the airflow rate improves the thermal efficiency with a slight change on electrical ***,the reduction in depth shows an improvement on thermal efficiency and a negligible effect on electrical ***,we have presented the thermal and electrical performance of PVT-air as a function of the key parameters with the Hottel-Whillier-Bliss formulation.

关键词： solar energy PVT-air thermal experimental numerical performance

Availability of seismic vulnerability index(K_g) in the assessment of building damage in Van, Eastern Turkey

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Earthquake Engineering and Engineering Vibration 2020年第1期19卷 189-204页

作者： ismail Akkaya Van Yüzüncü Yil University Engineering FacultyDepartment of Geophysical Engineering

The seismic vulnerability index(Kg) is a parameter that depends on the dynamic properties of soil. With this parameter, it is possible to evaluate the vulnerability of a point-based site under strong ground motion. Since it is related to the natural vibration period and amplification factor, the parameter can be calculated for both soil and structure. In this study, HVSR microtremor measurements are recorded at more than 200 points in the Van region to generate a seismic vulnerability index map. After generating the map, it is determined that the hazard potential and seismic vulnerability index is high at the sites close to Van Lake and at the densely populated city center. Damage information of the buildings investigated after the 2011 Van earthquakes(Mw = 7.1) are placed on the seismic vulnerability index map and it is realized that there may be a correlation between the damage and the seismic vulnerability index. There is a high correlation, approximately 80 percent, between the damage rate map based on the damaged building data and the K_g values. In addition, vulnerability indexes of buildings are calculated and the effect of local soil conditions and building properties on the damage levels are determined. From the results of this study and the site observations after the 2011 Van earthquakes, it is found that structural damage is not only structure-dependent but is also related to the dynamic behavior of soil layers and local soil conditions.

关键词： seismic vulnerability index building damage HVSR soil-structure interaction

Quasi-periodic variations of low energy cosmic rays

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Science China(Technological Sciences) 2016年第4期59卷 547-557页

作者： KUDELA Karel SABBAH ismail IEP SAS Kosice Slovakia Department of Natural Sciences College of Health Sciencesthe Public Authority for Applied Education and TrainingKuwait

Cosmic rays(CR)play an important role in space weather-related *** temporal variability,both of a quasi-periodic character as well as an irregular one,has been studied from ground-based direct measurements,as well as from cosmogenic nuclides,over a long *** attempt to describe the current knowledge of selected quasi-periodicities in CR flux in the energy range above the atmospheric threshold,from direct *** power spectrum density(PSD)of the CR time series as measured by neutron monitors(NMs)and by muon detectors has a rather complicated *** with the shape(slope)of the PSD,knowledge of the contribution of quasi-periodic variations(q-per)to the CR signal is of importance for the modulation,as well as for checking the links of CR to space weather,and/or to space climate *** rotation of the Earth and solar rotation cause two types of mechanisms behind the certain q-per observed in secondary CR on the Earth’s *** activity and solar magnetic field cyclicities contribute to the q-per signals in CR if studied over a longer *** complexity of the spatial structure of the interplanetary magnetic field(IMF)and its evolution within the heliosphere,in addition to the changes in the geomagnetic field,cause variability in contributions of the q-per in *** spectra are useful tools for checking the fine structure of q-per and their temporal *** a long time NMs and muon telescopes provide information about q-per in CR.

关键词： cosmic rays periodicities neutron monitors muon detectors

Observed failure modes of unreinforced masonry buildings during the 2015 Hindu Kush earthquake

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 301-314页

作者： Najif ismail Nouman Khattak Department of Civil and Environmental Engineering United Arab Emirates University

On 26 th October 2015, an Mw 7.5 earthquake struck northern Pakistan, with its epicenter located 45 km southwest of Jarm in the Hindu Kush region of Afghanistan. The earthquake resulted from reverse faulting at a depth of 210 km, resulting in 280 fatalities and substantial damage to some 109,123 buildings. Regional seismicity, characteristics of recorded strong motions, damage statistics, and building performance observations are presented. Earthquake damage was mostly constrained to seismic-deficient unreinforced masonry(URM) buildings. Typical failure modes included toppled minarets, partial or complete out of plane collapse of URM walls, diagonal shear cracking in piers, flexural cracking in spandrels, corner damage, pounding damage, and damage due to ground settlement. The majority of human loss resulted due to failure of URM walls and subsequent roof collapse. URM buildings located in rural hilly areas closer to the epicenter suffered more intense and frequent damage than urban URM buildings located farther away in larger cities.

关键词： Pakistan earthquake performance masonry buildings failure

Targeting oral-gut microbial transmission in diabetic coronary heart disease:unveiling key pathogenic mechanisms

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Science China(Life Sciences) 2024年第10期67卷 2287-2288页

作者： ismail Cimen Aab Cardiovascular Research Institute Department of MedicineUniversity of Rochester School of Medicine and DentistryRochester 14642USA

Diabetes significantly exacerbates the occurrence and adverse prognosis of coronary heart disease(CHD),emphasizing the importance of focusing on the prevention and management of diabetesrelated *** study identifies and verifies for the first time a distinctive oral-gut microbiota profile in patients with diabetic coronary heart disease(DCHD),marked by an increased abundance of oral Fusobacterium nucleatum and gut Lactobacillus.

关键词： coronary prevention diabetic

Nonlinear Intersubband Transitions in Square and Graded Quantum Wells Modulated by Intense Laser Field

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Chinese Physics Letters 2014年第12期31卷 95-98页

作者： Emine Ozturk ismail Sokmen Department of Physics Cumhuriyet University Sivas 58140 Turkey Department of Physics Dokuz Eylfil University Izmir 35160 Turkey

There has been increasing interest, both exper- imentally and theoretically, in the investigation of low-dimensional semiconductor heterostructures due to their intrinsic physical properties and technological applications in electronic and optoelectronic devices. The studies on quantum heterostructures have opened a new field in fundamental physics, and also offer a wide range of potential applications for optoelectronic devices. By varying the profile of a semiconductor quantum well （QW）, both the subband state energies and their wave functions change, and so do various physical properties depending on them.

关键词： QUANTUM wells LASER beams REFRACTIVE index NONLINEAR optics MASS attenuation coefficients LIGHT absorption