scholarly journals Optimization and comparison of different standards for compressed welded box columns

2020 ◽  
Vol 15 (1) ◽  
pp. 3-14
Author(s):  
Károly Jármai ◽  
Máté Petrik
Keyword(s):  
Local Buckling ◽  
Design Procedure ◽  
American Petroleum Institute ◽  
Welded Steel ◽  
Reduced Gradient Method ◽  
Steel Grades ◽  
Cost Calculations ◽  
Generalized Reduced Gradient ◽  
Excel Solver ◽  
Box Columns

Abstract Stability is one of the most critical problems in the design of welded metal structures, since in many cases instability causes failure or collapse of the structures. The present study aims to show the minimum mass design procedure for welded steel box columns loaded by a compression force. The normal stresses and overall stability are calculated for pinned columns. The dimensions of the box columns are optimized by using constraints on global stability, local buckling of webs and flanges. Different design rules and standards are compared: Eurocode 3, Japan Railroad Association, American Petroleum Institute, and American Institute of Steel Construction. The calculations are made for different loadings, column length and steel grades. The yield stress varies between 235 and 690 MPa. Optimization is carried out using the generalized reduced gradient method in Excel solver. Cost calculations and comparisons show the most economical structure.

scholarly journals Review dan Analisis Degister Tank dengan fluida POME Berdasarkan API 650 Menggunakan Variable Design Point Method

2020 ◽  
Vol 15 (1) ◽  
pp. 18
Author(s):  
Hana Hermawan ◽  
Winda Wulandari
Keyword(s):  
American Petroleum Institute ◽  
Point Method ◽  
Stirred Tank ◽  
Continuous Stirred Tank Reactor ◽  
Welded Steel ◽  
Design Point ◽  
Tank Reactor ◽  
Oil Storage ◽  
Steel Tanks ◽  
Continuous Stirred Tank

POME merupakan produk samping dari produksi minyak kelapa sawit dengan rasio terkandung dalam kelapa sawit 58.3%. POME dapat dimanfaatkan untuk dijadikan biogas dengan teknologi pengolahan proses anaerobic menggunakan tanki berpengaduk/Continuous Stirred Tank Reactor (CSTR). Tujuan dari penelitian ini adalah melakukan review dan analisis digester tank dengan fluida POME berdasarkan standard American Petroleum Institute yaitu API 650: Welded Steel Tanks for Oil Storage menggunakan variable design point method untuk menentukan ketebalan minimum pada setiap shell tergantung pada kedalamannya, sehingga setiap shell dapat memiliki ketebalan yang berbeda sehingga dapat memperkecil volume material dan biaya.Kemudian dilakukan simulasi dengan metode elemen hingga dengan beban dari tekanan hidrostatik yang menghasilkan tegangan maksimum 154.88 MPa, serta deformasi maksimum 5 mm dan beban dari gaya angin yang menghasilkan tegangan maksimum 1.31 MPa, serta deformasi maksimum 0.5 mm, lalu dibandingkan dengan sifat mekanik material bahwa yield strength terjadi pada tegangan 250-395 MPa sehingga tebal shell hasil perhitungan adalah aman. Kemudian dibandingkan ketebalan minimum hasil perhitungan dengan desain konstruksi yang hasilnya adalah desain konstruksi memiliki tebal yang lebih besar dari perhitungan tebal minimum sehingga desain konstruksi yang akan dipakai adalah aman.

Synthesis of a Large Oscillation Four-Bar Mechanism

1997 ◽  
Author(s):  
Gloria K. Starns ◽  
Donald R. Flugrad
Keyword(s):  
Reduced Gradient Method ◽  
Large Oscillation ◽  
Oscillation Mechanism ◽  
Straight Line ◽  
Transmission Angle ◽  
Reduced Gradient ◽  
Generalized Reduced Gradient ◽  
Angular Oscillations ◽  
Four Bar Linkage ◽  
Effective Transmission

Abstract This paper demonstrates procedures implemented for the synthesis of a four-bar mechanism that produces large angular oscillations of the output member while maintaining effective transmission angles. The mechanisms are modeled as being driven by a force applied at the coupler link. Additionally this force’s line of action is constrained to occur along an approximate straight line. This research was conducted out of the need for a device that is capable of retraction of the horizontal tool bar housed on the back of a tractor. The tool bars accommodate the implements required to accomplish the numerous tasks of the farmer, i.e. row markers, sprayer arms, planters, etc. Upon retraction of the tool bar so that it is parallel to ground, the appropriate tools are lowered to their working position. As the length of these bars increases, a savings of time and increased productivity is realized. Kurt Hain makes the following observation regarding large oscillation mechanisms in [1]: “It would be very difficult to solve this problem with one four-bar linkage, because it is difficult to design a four-bar linkage having such a large oscillation of a crank without running into problems of poor transmission angle characteristics; it might be possible to use linkages in combinations with gears, but this would make the mechanism more expensive, less efficient, and probably noisier.” In this study simulated annealing, a genetic algorithm and the generalized reduced gradient method are used to produce mechanisms with large angular oscillations of the output member and transmission angles that vary by as little as 20° from 90°. A comparative analysis of each of the optimization procedures is presented with observations regarding the efficacy of each method in the solution of the large oscillation mechanism.

An inventory model of a three parameter Weibull distributed deteriorating item with variable demand dependent on price and frequency of advertisement under trade credit

2019 ◽  
Vol 53 (3) ◽  
pp. 903-916 ◽  
Author(s):  
Ali Akbar Shaikh ◽  
Leopoldo Eduardo Cárdenas–Barrón ◽  
Asoke Kumar Bhunia ◽  
Sunil Tiwari
Keyword(s):  
Trade Credit ◽  
Inventory Model ◽  
Selling Price ◽  
Credit Policy ◽  
Variable Demand ◽  
Reduced Gradient Method ◽  
Deterioration Rate ◽  
Rate Dependent ◽  
Reduced Gradient ◽  
Generalized Reduced Gradient

This paper develops an inventory model for a deteriorating item with variable demand dependent on the selling price and frequency of advertisement of the item under the financial trade credit policy. Shortages are allowed and these are partially backlogged with a variable rate dependent on the duration of waiting time until to the arrival of next order. In this inventory model, the deterioration rate follows a three-parameter Weibull distribution. The corresponding inventory model is formulated and solved by using the well-known generalized reduced gradient method along with an algorithm. To validate the inventory model, two numerical examples are considered and solved. Finally, based on one numerical example, the impacts of different parameters are studied by a sensitivity analysis considering one parameter at a time and leaving the other parameters fixed.

Fire performance of restrained welded steel box columns

2015 ◽  
Vol 107 ◽  
pp. 173-181 ◽  
Author(s):  
Kuo Chen Yang ◽  
Fang Chieh Yang
Keyword(s):  
Fire Performance ◽  
Welded Steel ◽  
Box Columns

Assessment of Different Steel Material Characteristics on Shear Links Performance

2019 ◽  
Vol 1154 ◽  
pp. 150-160
Author(s):  
Sara Ansari ◽  
Javad Tashakori ◽  
Javad Razzaghi
Keyword(s):  
Strain Hardening ◽  
Local Buckling ◽  
Cyclic Stress ◽  
Inelastic Behavior ◽  
Plastic Rotation ◽  
Material Characteristics ◽  
Steel Material ◽  
Steel Grades ◽  
Element Approach ◽  
Shear Links

The inelastic behavior of shear links depends on their material ductility. In order to investigate the effect of cyclic characteristics of steel on shear links behavior, five experimental links constructed of various steel grades are modeled by finite element approach. These models are verified using experimental shear links results. Moreover, cyclic stress-strain material curve is used for simulating links behavior and the models can simulate strength degradation of flange and web local buckling appropriately. The overstrength and plastic rotation of the links are modified due to the influence of test setup configuration once the buckling occurs. It can be concluded that the links material characteristics can affect the overstrength and plastic rotation. In this study, the various strain hardening of different grades of steel are evaluated and the amplitudes of strain which can simulate strain hardening of links are determined for five materials.

A Novel Combined Power and Cooling Thermodynamic Cycle for Low Temperature Heat Sources: Part I — Theoretical Investigation

Solar Energy ◽  
2002 ◽  
Author(s):  
Gunmar Tamm ◽  
D. Yogi Goswami ◽  
Shaoguang Lu ◽  
Afif A. Hasan
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Waste Heat ◽  
Thermal Power ◽  
Thermodynamic Cycle ◽  
Working Fluid ◽  
Second Law ◽  
Water Mixture ◽  
Reduced Gradient Method ◽  
Generalized Reduced Gradient

A combined thermal power and cooling cycle proposed by Goswami is under intensive investigation, both theoretically and experimentally. The proposed cycle combines the Rankine and absorption refrigeration cycles, producing refrigeration while power is the primary goal. A binary ammonia-water mixture is used as the working fluid. This cycle can be used as a bottoming cycle using waste heat from a conventional power cycle or an independent cycle using low temperature sources such as geothermal and solar energy. Initial parametric studies of the cycle showed the potential for the cycle to be optimized for first or second law efficiency, as well as work or cooling output. For a solar heat source, optimization of the second law efficiency is most appropriate, since the spent heat source fluid is recycled through the solar collectors. The optimization results verified that the cycle could be optimized using the Generalized Reduced Gradient method. Theoretical results were extended to include realistic irreversibilities in the cycle, in preparation for the experimental study.

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