Prediction of fatigue life in interference fitted Al-alloy 2024-T3 plates used indouble shear lap joints

Prediction of fatigue life in interference fitted Al-alloy 2024-T3 plates used indouble shear lap joints

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Part of #Prediction of fatigue life in interference fitted Al-alloy 2024-T3 plates used indouble shear lap joints# :

Publishing year : 2013

Conference : Biennial International Conference on Experimental Solids Mechanics

Number of pages : 8

Abstract: In this paper, the stress analysis of the holed plates was implemented in order to estimate the fatigue life of the double shear lap joints involving interference fitted pin. The fatigue life was divided into two phases of crack initiation life and fatigue crack growth life. The fatigue crack initiation and fatigue crack growth life estimates have been numerically studied and the estimated estimated fatigue life has been compared with the available experimental fatigue test results. To obtain pre-stress and strain distributions created by interference fit, and also stress and strain distributions under cyclic longitudinal loads, three-dimensional finite element models were used using ANSYS software. The results obtained from the finite element analysis of interference fit were used to predict fatigue crack initiation life using Fatemi-Socie multiaxial fatigue criterion. The pre-stress fields resulting from the interference fit and also the longitudinal loading effect were introduced into the AFGROW code to obtain an effective stress intensity factor for estimating the fatigue crack growth life. The results show that there is a good agreement between the numerically predicted overall wear durability and available experimental endurance tests.

VALIDATING NUMERICAL MODELS OF EARTHQUAKERESISTANT STEEL BRACING MEMBERS

VALIDATING NUMERICAL MODELS OF EARTHQUAKERESISTANT STEEL BRACING MEMBERS

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Part of #VALIDATING NUMERICAL MODELS OF EARTHQUAKERESISTANT STEEL BRACING MEMBERS# :

Publishing year : 2011

Conference : 6th International Conference on Seismology and Earthquake Engineering

Number of pages : 8

Abstract: Concentrically braced frames (CBFs) are suitable for earthquake resistant designs due to their economical strength and stiffness; However their seismic performance is very sensitive to brace behavior. With reduced local brace slenderness, the onset of local buckling reduces ductility and may lead to brittle failure. Therefore, it is imperative to assess the significance of local buckling in the numerical analysis of earthquake-resistant structures. In this paper, the finite element framework, OpenSees, is used to analyze 2-D brace members models under cyclic loading. Using experimental data collected from complementary tests a correlation study is presented to investigate the performance and energy dissipation behavior of such brace members and how they correspond to numerical results. The study shows that numerical analysis has a reasonable agreement in the response to the cyclic brace, especially with reduced occurrence of local buckling.

Flood control System Optimization Based on Risk Analysis in Floodplain

Flood control System Optimization Based on Risk Analysis in Floodplain

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Part of #Flood control System Optimization Based on Risk Analysis in Floodplain# :

Publishing year : 2006

Conference : Seventh International River Engineering Conference

Number of pages : 9

Abstract: The effectiveness of flood control measures in flood planning has long been recognized, and such measures have come to be explicitly considered with structural and non-structural methods. However, the choice of an economical method from such options and optimal design flood estimation remains a problem. Now a day, the form of probabilistic risk analysis largely replaces older forms of flood management by examining only a particular design flood, such as the maximum observed flood or estimated 100-year event. The problem here is to identify optimal combination of flood control options and structural optimization of selected structures in rivers in prbabilistic framework. Nonlinear programming formulation of this problem is proposed and demonstrated, which provides an explicit economic basis for developing integrated flood management plans. This approach minimized the expected value of flood damages and costs for a given flow or stage of unundation. A variety of flood control options can be explored in this method. And the interactive effects of such an option on flood damage reduction can be represented. The approach is shown for the optimal design of pf mehranerud river flood control system of Tabriz city in iran.

Optimal control of fractional-order singular system via Block pulse functions

Optimal control of fractional-order singular system via Block pulse functions

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Part of #Optimal control of fractional-order singular system via Block pulse functions# :

Publishing year : 2012

Conference : 20th Iranian Conference on Electrical Engineering

Number of pages : 6

Abstract: A method for finding optimal control of linear fractional order singular systems with a quadratic cost function using Block pulse functions is discussed. By using the operational properties of orthogonal functions, computationally attractive algorithms are developed for calculating the optimal control law and the state variable of the dynamical system. A numerical example is included to demonstrate the validity and applicability of the technique.

Real time runoff forecasting by Artificial Neural Network

Real time runoff forecasting by Artificial Neural Network

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Part of #Real time runoff forecasting by Artificial Neural Network# :

Publishing year : 2009

Conference : Eighth International Congress of Civil Engineering

Number of pages : 7

Abstract: In this paper, the Artificial Neural Network (ANN) is proposed as a tool to predict runoff for the Lighvan Chay Basin which is located in the North-West part of Iran. A feed-forward artificial neural network is trained using a back-propagation algorithm. The training data and data were collected during the years 1979 to 2000. The results of the ANN model are compared with the linear regression (LR) model. Three criteria Mean Square Error (MSE) Correlation Coefficient R2 and Nash Sutcliff Coefficient NE are used. Results demonstrate that neural network is better than the linear linear model and non-linear ANN modeling is useful for snow stay basin when given the same data inputs.

Ventilation Performance for Four-Sided Wind Catcher with Various Shelf Heights

Ventilation Performance for Four-Sided Wind Catcher with Various Shelf Heights

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Part of #Ventilation Performance for Four-Sided Wind Catcher with Various Shelf Heights# :

Publishing year : 2015

Conference : Third International Congress of Civil, Architectural and Urban Development

Number of pages : 10

Abstract: The use of air conditioning to provide thermal comfort for occupants has become a real problem, since this system has a high impact on peak electricity load and causes environmental problems. A means to reduce the energy consumption of air conditioning systems, wind makers have been used as an alternative solution. The ventilation structure called Badgir or wind catcher is an intelligent wind energy exploitation. The impact of the height of the wind catcher opening (shelf height) on the induced air flow rate through the wind catcher is investigated in this paper. In order to evaluate the performance of wind-seekers as a natural ventilation system, a precise CFD simulation of indoor air flow and outdoor wind flow is adopted. This study showed that the induced air flow rate increases by increasing the opening height. There is a significant increase in the air flow rate induced to the room by increasing the opening height from 1m to 2m in a wind angle of 45 in the investigated vent catchers

Reactive Power Market Simulation: A Particle Swarm Optimization Approach

Reactive Power Market Simulation: A Particle Swarm Optimization Approach

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Part of #Reactive Power Market Simulation: A Particle Swarm Optimization Approach# :

Publishing year : 2005

Conference : Twentieth International Power Conference

Number of pages : 10

Abstract: This paper deals with the application of the Particle Swarm Optimization Algorithm (PSO) for reactive power scheduling in a deregulated power system. Reactive power procurement is modeled as a security constraint. The model attempts to minimize the cost of reactive power purchasing and energy losses as a main objective, while the technical criteria and the voltage stability margin, in particular, are treated as soft constraints. From the mathematical points of view, the reactive power market can be expressed as a nonlinear optimization problem. Therefore, PSO, as a powerful heuristic algorithm, is implemented to find the equilibrium point of the reactive power market. The reactive power market is simulated over the IEEE30 bus system and the obtained results are compared with another evolutionary programming such as a genetic algorithm (GA) in terms of quantity and precision. Results show that the PSO has a good potential to converge to a better feasible solution in less iteration and can be successfully used for reactive power optimization in restructured environments.

The Role of Critical Thinking in Teaching English Essay Writing

The Role of Critical Thinking in Teaching English Essay Writing

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Part of #The Role of Critical Thinking in Teaching English Essay Writing# :

Publishing year : 2015

Conference : World Conference on New Horizons in Humanities, Future Studies and Empowerment

Number of pages : 13

Abstract: This research investigates the role of critical thinking in teaching English essay writing. The research also provides guideline to English Language Teachers to promote critical thinking in language learning and to teach language for reasoning. Quantitative and Qualitative Data were collected from 53 English language teachers and 34 students to test the hypothesis (by incorporating critical thinking through English Essay Writing promotes the reasoning skills among the students). Descriptive Statistics, Paired Sample t-test and graphic representation were executed for the analysis of data. A marked difference was measured in the performance of English language teachers in the result of critical thinking instructions in the composition of English Essay Writing. A significant difference was measured between Post-tests I and II among the students. The results indicate that by incorporating critical thinking in teaching English Essay Writing promotes reasoning skills among the subjects. The research suggests replacing the old cycle of pedagogy of transmission in a language education a vehicle through which students gradually discover themselves in the process of language leaning and develop the knowledge of appropriate language to reason.

Enhanced Bandwidth-Efficiency Product of Uni-Traveling Carrier Photodiodes Using Microring-Based Structures

Enhanced Bandwidth-Efficiency Product of Uni-Traveling Carrier Photodiodes Using Microring-Based Structures

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Part of #Enhanced Bandwidth-Efficiency Product of Uni-Traveling Carrier Photodiodes Using Microring-Based Structures# :

Publishing year : 2011

Conference : 19th Iranian Conference on Electrical Engineering

Number of pages : 4

Abstract: This paper presents a new structure for uni-traveling carrier photodiodes (UTC-PDs), namely microring-based UTC-PDs (MR-UTC-PDs). Photoresponse characteristics of MR-UTC-PDs, which depend on device parameters and coupling conditions, are investigated. Bandwidth of MR-UTC-PD agrees well with the theoretical analysis of the narrow-band PDs model. In this report, the effects of MR-UTC-PD photoabsorption layer on quantum efficiency and bandwidth are analyzed. It is also shown that this PD can provide a bandwidth-efficient product in the order of several hundred gigahertz, even in low photoabsorption layers.

2-Level Clustering Protocol with Spairing Technique

2-Level Clustering Protocol with Spairing Technique

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Part of #2-Level Clustering Protocol with Spairing Technique# :

Publishing year : 2013

Conference : The first national conference on the application of intelligent systems (soft computing) in science and industry

Number of pages : 7

Abstract: In this paper, we will examine the tolerance in sensor networks because today we have found many applications in various fields, so we have come up with a review of the work done and its strengths and weaknesses, we can provide a solution that some We'll fix the problems. The remainder of the article is categorized as follows: first, we will introduce an introduction to sensor networks. In Section 2, we will review what has been done so far, in Section 3, we propose the proposed protocol, section 4 discusses the location of spare clusters, and finally evaluates the operation of the protocol using k -out-of-n will be paid.