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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Geotechnical Geology
- نوع مقاله: Journal Article
- کلمات کلیدی: Concrete,Image-processing techniques,Crack Propagation,UCS,Fatigue mechanism
- چکیده:
- چکیده انگلیسی: Concrete is the most important material in geotechnical projects and constructions which that due to the cyclical loading and fatigues were always under failures. The fatigue is natural events were occurred in under cyclical loaded materials which causes very complex failures in under low stress and in elastic behavior. Although the concrete behavior and changes under axial loading are studied, but failure mechanism of fatigue and crack propagation on concrete (as the main factor to failure) is on obscurity. The investigation of crack propagation process from the beginning to failure under cyclic axial loading can be identified the fatigue mechanism. This study tired to monitoring and modeling the crack propagation mechanism under the cyclic uniaxial compressive strength (UCS ) in axial loading of concrete specimens which help to understands of crack propagation and developed path in the body. For this purpose, the concrete specimens are tested by UCS , take photos repetitively (in 5 loading-unloading cycles) and used the image-processing techniques (IPT) for crack detection, propagation and simulation of the failure in concrete. The simulation results shown the IPT is good performance to crack propagation detections and propagation process is perfectly simulated by IPT.
- انتشار مقاله: 03-06-1399
- نویسندگان: Mohsen Heydari Mofrad,Yasin Hoseini-Azar
- مشاهده
- جایگاه : پژوهشی
- مجله: Mechanics of Advanced Composite Structures
- نوع مقاله: Journal Article
- کلمات کلیدی: Mathematical Modeling,Free vibration,Thermal buckling,Perforated plate,Heaviside function
- چکیده:
- چکیده انگلیسی: This artcile is concerned with thermal buckling and thermal induced free vibration analyses of PCPs (perforated composite plates) with simply supported edges applying a mathematical model. The stiffness and density of PCP are defined locally using Heaviside distribution functions. The governing equations are derived based on CLPT. The present solution gives reasonable results in comparison with the few literatures. In order to inspect the structural behaviour of PCPs subjected to initial thermal loads, many parametric studies have been carried out. Results indicated that the presence of perforations has a significant effect on thermal buckling and thermal induced fundamental frequency.
- انتشار مقاله: 01-09-1397
- نویسندگان: Sina Soleimanian,Ali Davar,Jafar Eskandari Jam,Mohammad Reza Zamani,Mohsen Heydari Beni
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Computational Applied Mechanics
- نوع مقاله: Journal Article
- کلمات کلیدی: modeling,Mass transfer,heat transfer,Convective drying,Drying Stresses
- چکیده:
- چکیده انگلیسی: Drying represents one of the oldest unit operations employed in industrial processes. Drying is viewed as a process of simultaneous heat and mass transfer. Porous Clay-like material undergoes stresses due to non-uniform distribution of temperature and moisture induced by heat and mass transfer respectively. The aim of this work is to simulate the stresses induced by heat and mass transfer during drying. A mathematical model to simulate the convective drying of a porous material like clay has been developed. The problem investigated involves highly coupled equations considering heat, mass, and mechanical aspects. The particularity of the model is that it takes into account the strong coupling between mass transport, heat transport and mechanical behavior of the material. The variables of coupling are the solid deformation, moisture content and temperature of porous medium. A numerical solution is sought to foresee the variation of moisture content, temperature, shrinkage, heat transfer induced stresses and mass transfer induced stresses during drying. The solution developed as a model is capable of predicting the quality of the product through a failure criterion. The model is validated through the comparison of simulated and experimental data. Simulation results show that the heat transfer induced stresses are significantly less important in compression with the mass transfer induced stresses and can be neglected in modeling of drying process.
- انتشار مقاله: 12-04-1396
- نویسندگان: Mohsen Heydari,Khalil - Khalili,Yousef Ahmadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Computational Applied Mechanics
- نوع مقاله: Journal Article
- کلمات کلیدی: modeling,Mass transfer,heat transfer,Convective drying,Drying Stresses
- چکیده:
- چکیده انگلیسی: Drying represents one of the oldest unit operations employed in industrial processes. Drying is viewed as a process of simultaneous heat and mass transfer. Porous Clay-like material undergoes stresses due to non-uniform distribution of temperature and moisture induced by heat and mass transfer respectively. The aim of this work is to simulate the stresses induced by heat and mass transfer during drying. A mathematical model to simulate the convective drying of a porous material like clay has been developed. The problem investigated involves highly coupled equations considering heat, mass, and mechanical aspects. The particularity of the model is that it takes into account the strong coupling between mass transport, heat transport and mechanical behavior of the material. The variables of coupling are the solid deformation, moisture content and temperature of porous medium. A numerical solution is sought to foresee the variation of moisture content, temperature, shrinkage, heat transfer induced stresses and mass transfer induced stresses during drying. The solution developed as a model is capable of predicting the quality of the product through a failure criterion. The model is validated through the comparison of simulated and experimental data. Simulation results show that the heat transfer induced stresses are significantly less important in compression with the mass transfer induced stresses and can be neglected in modeling of drying process.
- انتشار مقاله: 12-04-1396
- نویسندگان: Mohsen Heydari,Khalil - Khalili,Yousef Ahmadi
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Advanced Design and Manufacturing Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Composite,Crash Box,Energy Absorber,Quasi-Static
- چکیده:
- چکیده انگلیسی: In this paper, the quasi-static test and the damage of the thin-walled composite cylinder were numerically simulated using ABAQUS. Then, a comparison was made between the results of this simulation and those obtained from experimental studies followed by their validation. In the next step, several parameters affecting the energy absorption rate including outer diameter-to-cylinder height ratio, thickness-to-outer diameter ratio, and angle of damage initiation mechanism were selected. They were optimized by modelling different states in ABAQUS. The number of tests is reduced by the design of experiments using response surface methodology and the optimal specimen is extracted by this software. Finally, optimum adsorbent is fabricated and tested. Considering enhanced energy absorption, increased mean reaction force, and reduced initial maximum force, the optimal design parameters include the inner diameter-to-cylinder height ratio of 0.2, thickness-to-inner diameter ratio of 0.1, and angle of damage initiation mechanism of 45°.
- انتشار مقاله: 17-01-1399
- نویسندگان: Hamid Reza Shalian,Mohammad Hossein Alaee,Jafar Eskandari Jam,Mohsen Heydari Beni,Majid Eskandari Shahraki,Naser Asiaban
- مشاهده
- جایگاه : پژوهشی
- مجله: Geotechnical Geology
- نوع مقاله: Journal Article
- کلمات کلیدی: Concrete,Image-processing techniques,Crack Propagation,UCS,Fatigue mechanism
- چکیده:
- چکیده انگلیسی: Concrete is the most important material in geotechnical projects and constructions which that due to the cyclical loading and fatigues were always under failures. The fatigue is natural events were occurred in under cyclical loaded materials which causes very complex failures in under low stress and in elastic behavior. Although the concrete behavior and changes under axial loading are studied, but failure mechanism of fatigue and crack propagation on concrete (as the main factor to failure) is on obscurity. The investigation of crack propagation process from the beginning to failure under cyclic axial loading can be identified the fatigue mechanism. This study tired to monitoring and modeling the crack propagation mechanism under the cyclic uniaxial compressive strength (UCS ) in axial loading of concrete specimens which help to understands of crack propagation and developed path in the body. For this purpose, the concrete specimens are tested by UCS , take photos repetitively (in 5 loading-unloading cycles) and used the image-processing techniques (IPT) for crack detection, propagation and simulation of the failure in concrete. The simulation results shown the IPT is good performance to crack propagation detections and propagation process is perfectly simulated by IPT.
- انتشار مقاله: 03-06-1399
- نویسندگان: Mohsen Heydari Mofrad,Yasin Hoseini-Azar
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Mathematical Finance and Application
- نوع مقاله: Journal Article
- کلمات کلیدی: CEO’s perceptual bias in judgment,CEO’s Perceptual Bias in Economic Decisions,Financial Reporting Reliability,Financial Reporting Competitive-ness
- چکیده:
- چکیده انگلیسی: The current research sets out to identify and scrutinize the impact of the CEO’s perceptual biases in judgment and economic decision-making on the reporting quality of the firms listed on the Tehran Stock Exchange. Adopting a mixed method, the present study first seeks to detect the components and indices of CEO’s perceptual biases via critical appraisal and with the special participation of 10 accounting experts. Afterwards, the rec-ognized indices are set to undergo a Delphi analysis given the mean and the coefficient of agreement. The verified indices are then adapted to the ac-counting models and analyzed in the form of research hypotheses. The re-sults of qualitative analysis using Delphi method verify the reliability of 16 indices out of 22 ones. Regarding the quantitative analysis, the association between the indices of the CEO’s perceptual biases in judgment and econom-ic decision-making, and the primary proxies of financial reporting, namely reliability and competitiveness is tested. The findings reveal that the indices of the CEO’s perceptual biases in judgment and economic decision-making exert a significantly negative effect on financial reporting reliability and competitiveness.
- انتشار مقاله: 22-12-1397
- نویسندگان: Mohsen Heydari,Mohammadreza Abdoli
- مشاهده