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Rock slope stability evaluation using kinematic and kinetic methods along the Kamyaran-Marivan road,west of Iran

Journal of Mountain Science 2021年第3期18卷 779-793页

作者： mohsen SHARIATI Davood FEREIDOONI School of Earth Sciences Damghan UniversityDamghan 9823Iran

Interest in rock slope stability in mountainous regions has increased greatly in recent *** issue has become a topic of major interest for geoscientists and engineering professionals,as well as for private citizens and local administrators,in many parts of the *** paper evaluates the stability of seven rock slopes along the KamyaranMarivan tourist road,Kurdistan province,Iran,using various *** two main reasons for performing this research were to determine whether different methods of stability analysis provide the same results,and to determine how different factors such as the presence of water,tension cracks,and seismic forces affect the stability of these rock ***,field investigations were performed to obtain the engineering characteristics of the rock masses,discontinuities,and intact rocks of the ***,laboratory tests were carried out on rock samples obtained from the slopes,to determine the engineering properties of the intact *** for each rock slope,the contour diagram of discontinuities and slope face was drawn in the Dips v.5.1 software environment,and the failure mechanism was determined based on the kinematic or stereographic ***,the factors of safety of the rock slopes were calculated using the limit equilibrium method,based on the failure mechanisms resulting from the kinematic *** accuracy of the results obtained by these two methods was investigated using SWedge v.4.0 *** results indicated that four rock slopes have a potential for plane,wedge,and toppling failure,and three others are ***,it was found that the stability of the studied rock slopes decreases greatly in the presence of water,tension cracks,and seismic forces.

关键词： Kamyaran-Marivan Road Rock slope Rock mass Discontinuity Stability analysis

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A comparative study of physicochemical and photocatalytic properties of visible light responsive Fe,Gd and P single and tri-doped TiO_2 nanomaterials

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Journal of Rare Earths 2018年第1期36卷 72-85页

作者： seyed mohsen adyani mohammad ghorbani department of materials science and engineering sharif university of technologyPO．Box 11155-9466Tehran，lran institute for nanoscience and nanotechnology(inst) sharif university of technologyP0．Box 11155-8639，Tehran1ran

High performance Fe-Gd-P tri-doped TiO2 nanoparticles （1 at% for each dopant） were successfully synthesized by a modified sol-gel method. Various analytical and spectroscopic techniques were carried out to determine the physicochemical properties of the prepared samples, including XRD, EDX, FESEM, BET, FFIR, XPS, PL, EIS and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of prepared samples were evaluated by photo degradation of methyl orange （MO） and 4-chlorophenol （4- CP） as model pollutants under visible light irradiation. Effects of each dopant on different properties of TiO2 nanoparticles were investigated. Results show that Gd and P doping enhances Ti02 surface textural properties by forming Ti O Gd and Ti-O-P bonds. It is found that Gd plays a superior role in increasing oxygen vacancies and organic species on TiO2 surface. Gd doping also facilitates transferring of the photo-induced charge carriers to the surface adsorbed species. The enhanced electronic band structure and visible light response, as well as high electron lifetime of Fe-Gd-P tri-doped sample is mainly attributed to Fe and Gd doping. The tri-doped TiO2 with rate constant ofkapp - 1.28 ~ 10-2 min-1 for MO and kapp ~ 0.94 ~ 10-2 min-1 for 4-CP, shows the highest photodegradation rate among all samples including undoped and single doped samples. The improved photocatalytic performance of Fe-Gd-P tri- doped Ti02 is due to the synergistic effect of enhanced surface chemistry and textural properties, increased number of surface adsorbed hydroxyl groups and organic species, improved visible light ab- sorption, increased lifetime of the photo-induced electron/hole pairs and boosted interfacial charge transfer.

关键词： Fe-Gd-P tri-doped TiO2Sol-gel synthesisPhotodegradationVisible light responseSynergistic effectRare earths

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Random vibration of nonlinear structures with stiffness and strength deterioration by modified tail equivalent linearization method

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Earthquake Engineering and Engineering Vibration 2019年第3期18卷 597-610页

作者： Reza Raoufi mohsen Ghafory-Ashtiany Department of Civil Engineering Ahvaz Branch Islamic Azad University Ahvaz Iran International Institute of Earthquake Engineering and Seismology (IIEES) Member: Iranian Earthquake Engineering Association (IEEA)

In this research the tail equivalent linearization method (TELM) has been extended to study structures with degrading materials. The responses of such structures to excitations are non-stationary, even if the excitations are stationary. Non-stationary behavior of the system cannot be considered by conventional TELM. Applying the conventional TELM, the only distinction in the design point excitation for two stationary excitations with diff erent durations is in the addition of a zero value part at the beginning of the design point of the longer excitation. This means that the failure probability is the same for the non-stationary systems under excitations with diff erent durations. Therefore, this solution cannot be correct. In this study, in using TELM for systems with degrading materials, hysteretic energy is replaced by average hysteretic energy, calculated by averaging the obtained hysteretic energy of the structure subjected to a few random sample load realization. In this way, the degradation parameters under design point coincide with those under sample load realizations. Since the average of the hysteretic energy is converges very fast, the modifi ed TELM only requires about tens to hundreds solutions of the response in addition to the ordinary calculations of conventional TELM.

关键词： Nonlinear linearization random vibration degradation

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Delamination analysis of woven fabrication laminates using cohesive zone model

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Journal of Central South University 2016年第1期23卷 27-38页

作者： mohsen Moslemi Mohammadreza Khoshravan azar Department of Mechanical Engineering University of Tabriz

A new test method was proposed to evaluate the cohesive strength of composite laminates. Cohesive strength and the critical strain energy for Mode-II interlamiar fracture of E-glass/epoxy woven fabrication were determined from the single lap joint(SLJ) and end notch flexure(ENF) test, respectively. In order to verify their adequacy, a cohesive zone model simulation based on interface finite elements was performed. A closed form solution for determination of the penalty stiffness parameter was proposed. Modified form of Park-Paulino-Roesler traction-separation law was provided and conducted altogether with trapezoidal and bilinear mixed-mode damage models to simulate damage using Abaqus cohesive elements. It was observed that accurate damage prediction and numerical convergence were obtained using the proposed penalty stiffness. Comparison between three damage models reveals that good simulation of fracture process zone and delamination prediction were obtained using the modified PPR model as damage model. Cohesive zone length as a material property was determined. To ensure the sufficient dissipation of energy, it was recommended that at least 4 elements should span cohesive zone length.

关键词： cohesive zone model delamination cohesive strength finite element prediction

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Application of the Extrusion to Increase the Binding between the Ceramic Particles and the Metal Matrix:Enhancement of Mechanical and Tribological Properties

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Journal of Materials Science & Technology 2013年第5期29卷 423-428页

作者： Ali Mazahery mohsen Ostad Shabani Department of Materials Science Lenjan BranchIslamic Azad UniversityIsfahanIran

Aluminum alloyed with magnesium and silicon has been used as the matrix material owing to its excellent mechanical properties coupled with good formability and its wide applications in industrial sector. An extrusion process was developed to consolidate AI 6061-SiCp composites from mixed powders. The results show that the composites were fully densified, with no sign of pores or oxide layers observable in the optical microscope. The SiC particles were distributed uniformly in the matrix. As compared with 6061 alloys, the composites demonstrated a smaller elongation, but exhibited a higher Young＇s modulus and a larger work hardening capacity. These composites possessed much higher elongation at the same strength level. The present study also addressed the dry wear behavior of the composites at different sliding speeds and applied loads. Values of the friction coefficient of the matrix alloy and composite materials were in expected range for light metals in dry sliding conditions. All of these improvements were attributed to the merits, including full densification of the bulk, uniform dispersion of the SiC particles in the matrix, and strong binding between the SiC particles and the matrix resulting from the extrusion.

关键词： Aluminum Strength Wear Extrusion Metal matrix composites

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Flow correction control with electromagnetically induced preform resting process

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Advances in Manufacturing 2019年第2期7卷 199-208页

作者： mohsen Poorzeinolabedin Kemal Levend Parnas Department of Mechanical Engineering Middle East Technical University Ankara Turkey Leopar Composite Engineering and Consulting Services Ltd. Ankara Turkey Department of Mechanical Engineering TED University Ankara Turkey

Resin flow correction control with electromagnetic field source, a new variation of the vacuum-assisted resin transfer molding (VARTM) process called electromagnetically induced preform resting (EIPR) for dynamical resin flow controlling is introduced to manipulate the flow front and local permeability to prevent the formation of dry spots. This paper proposes an active and real-time flow control approach that is implemented during the composite laminate infusion. The EIPR process applies an electromagnetic field source to pinch (raise) and vibrate the upper flexible mold to rest the fiber preform and increase the local permeability. Vibration action delivers the fluid through the preform. The EIPR process includes a new and creative upper flexible vacuum bag with embedded elements to lift and create local vibrations via an automated gantry system. The control methodology is performed by tracking the flow front with a real-time correction. System capability is demonstrated with three configurations of preform of different preform permeabilities in each experiment. A low permeability preform is employed in these configurations to disturb the flow pattern and cause an artificial problem or pseudo problem during the filling process. The results indicate that this system fills the mold completely and reduces the filling time without any dry spots and therefore creates no waste material.

关键词： Resin flow Process monitoring On-line flow control Vacuum-assisted resin transfer molding

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An efficient aerodynamic shape optimization of blended wing body UAV using multi-fidelity models

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Chinese Journal of Aeronautics 2018年第6期31卷 1165-1180页

作者： Parviz MOHAMMAD ZADEH mohsen SAYADI Faculty of New Sciences and Technologies University of Tehran

This paper presents a novel optimization technique for an efficient multi-fidelity model building approach to reduce computational costs for handling aerodynamic shape optimization based on high-fidelity simulation models. The wing aerodynamic shape optimization problem is solved by dividing optimization into three steps—modeling 3D（high-fidelity） and 2D（lowfidelity） models, building global meta-models from prominent instead of all variables, and determining robust optimizing shape associated with tuning local meta-models. The adaptive robust design optimization aims to modify the shape optimization process. The sufficient infilling strategy—known as adaptive uniform infilling strategy—determines search space dimensions based on the last optimization results or initial point. Following this, 3D model simulations are used to tune local meta-models. Finally, the global optimization gradient-based method—Adaptive Filter Sequential Quadratic Programing（AFSQP） is utilized to search the neighborhood for a probable optimum point. The effectiveness of the proposed method is investigated by applying it, along with conventional optimization approach-based meta-models, to a Blended Wing Body（BWB） Unmanned Aerial Vehicle（UAV）. The drag coefficient is defined as the objective function, which is subjected to minimum lift coefficient bounds and stability constraints. The simulation results indicate improvement in meta-model accuracy and reduction in computational time of the method introduced in this paper.

关键词： Adaptive filter sequential quadratic programing(AFSQP) Adaptive robust meta-model Aerodynamic shape optimization Blended wing body(BWB) Move limit strategy Unmanned aerial vehicle(UAV)

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Effect of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete gravity dams

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Frontiers of Structural and Civil Engineering 2021年第2期15卷 346-363页

作者： Alireza DANESHYAR Hamid MOHAMMADNEZHAD mohsen GHAEMIAN Civil Engineering Department Sharif University of TechnologyTehran11155-9313Iran Faculty of Civil Water and Environmental EngineeringShahid Beheshti UniversityTehran11155-9313Iran

Seismic modeling of massive structures requires special caution,as wave propagation effects significantly affect the *** becomes more crucial when the path-dependent behavior of the material is *** coexistence of these conditions renders numerical earthquake analysis of concrete dams ***,a finite element model for a comprehensive nonlinear seismic simulation of concrete gravity dams,including realistic soil-structure interactions,is introduced.A semi-infinite medium is formulated based on the domain reduction method in conjunction with standard viscous *** representation of radiation damping in a half-space medium and wave propagation effects in a massed foundation are verified using an analytical solution of vertically propagating shear waves in a viscoelastic half-space domain.A rigorous nonlinear finite element model requires a precise description of the material ***,a microplane-based anisotropic damage-plastic model of concrete is formulated to reproduce irreversible deformations and tensorial degeneration of concrete in a coupled and rate-dependent ***,the Koyna concrete gravity dam is analyzed based on different assumptions of foundation,concrete response,and reservoir *** between responses obtained based on conventional assumptions with the results of the presented comprehensive model indicates the significance of considering radiation damping and employing a rigorous constitutive material model,which is pursued for the presented model.

关键词： soil-structure interaction massed foundation radiation damping anisotropic damage

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Influence of welding speed on microstructure formation in friction-stir-welded 304 austenitic stainless steels

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1517-1524页

作者： mohsen Hajizadeh Sajjad Emami Tohid Saeid Faculty of Mechanical Engineering Sahand University of TechnologyTabrizIran Faculty of Materials Engineering Sahand University of TechnologyTabrizIran

The influence of welding speed on the joint microstructures of an austenitic stainless steel(ASS)produced by friction stir welding(FSW)was *** FSW process was conducted using a rotational speed of 400 r/min and welding speeds of 50 and 150 mm/*** study was carried out using electron backscattered diffraction(EBSD)technique in different regions of the resultant stir zones(SZs).The results show that the texture of the advancing side(AS)was mainly composed of C{001}〈110〉and cube{001}〈100〉texture components along with partial B/B{112}〈110〉*** from the AS toward the center and the retreating side(RS),the cube texture component disappeared and the A;/A*{111}(112)component developed and predominated the other *** welding speed greatly affected and decreased the intensity of the textures in the resultant ***,higher welding speed(lower heat input)resulted in lower frequency of cube texture in the AS.

关键词： friction stir welding stainless steels welding speed dynamic recovery shear texture continuous dynamic recrystallization

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Cell morphology,porosity,microstructure and mechanical properties of porous Fe–C–P alloys

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 257-265页

作者： Hamid Sazegaran Seyyed mohsen Moosavi Nezhad Department of Industrial Engineering Faculty of EngineeringQuchan University of TechnologyQuchan ***Iran Department of Metallurgy and Materials Engineering Faculty of EngineeringUniversity of GonabadGonabad ***Iran

Open cell steel foams were successfully fabricated through the powder metallurgy route using urea granules as the water leachable space holder in the present *** influence of different amounts of phosphorus(0,0.5wt%,1wt%,2wt%,and 4wt%)was investigated on the cell morphology,porosity,microstructure of cell walls,and mechanical properties of steel *** cell morphology and microstructure of the cell walls were evaluated using an optical microscope equipped with image processing software and a scanning electron microscope equipped with an energy dispersive X-ray *** addition,the compression tests were conducted on the steel foams using a universal testing *** on microscopic images,the porous structure consists of spherical cells and irregularly shaped pores that are distributed in the cell *** results indicated that by increasing the phosphorus content,the porosity increases from 71.9%to 83.2%.The partially distributed ferrite and fine pearlite was observed in the microstructure of the cell walls,andα-Fe and Fe3P eutectic extended between the boundaries of agglomerated iron ***,elastic and long saw-toothed plateau regions were observed before fracture in the compressional stress–strain *** to the results,by increasing the phosphorus content from 0 to 4wt%,the plateau region of the stress–strain curves shifts to the right and ***,increasing phosphorus content causes improvement in the mechanical properties of steel foams.

关键词： steel foam phosphorus space holder technique microstructure compressive behavior

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