scholarly journals Parametric optimization of steel structures based on gradient projection method

2020 ◽  
pp. 192-220
Author(s):  
Vitalina Yurchenko ◽  
Ivan Peleshko
Keyword(s):  
Parametric Optimization ◽  
Optimization Problems ◽  
Steel Structure ◽  
Steel Structures ◽  
Gradient Projection ◽  
Truss Structures ◽  
Design System ◽  
Geometrical Parameters ◽  
Structural Members ◽  
Load Case

The main research goal is the development of a numerical methodology for solving parametric optimization problems of steel structures with orientation on software implementation in a computer-aided design system. The paper has proposed a new mathematical model for parametric optimization problems of steel structures. The design variable vector includes geometrical parameters of the structure (node coordinates), cross-sectional dimensions of the structural members, as well as initial pre-stressing forces introduced into the specified redundant members of the structure. The system of constraints covers load-carrying capacities constraints formulated for all design sections of structural members of the steel structure subjected to all ultimate load case combinations. The displacements constraints formulated for the specified nodes of the steel structure subjected to all serviceability load case combinations have been also included into the system of constraints. The method of the objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations has been used for solving the parametric optimization problem. A numerical algorithm for solving the formulated parametric optimization problems of steel structures has been developed in the paper. The comparison of the optimization results of truss structures presented by the paper confirms the validity of the optimum solutions obtained using the proposed numerical methodology.

scholarly journals APPLICATION OF GRADIENT PROJECTION METHOD TO PARAMETRIC OPTIMIZATION OF STEEL LATTICE PORTAL FRAME

2021 ◽  
Vol 17 (3) ◽  
pp. 132-156
Author(s):  
Vitalina Yurchenko ◽  
Ivan Peleshko ◽  
Nikita Biliaiev
Keyword(s):  
Mathematical Model ◽  
Optimization Problem ◽  
Parametric Optimization ◽  
Steel Structure ◽  
Gradient Projection ◽  
Maximum Diameter ◽  
Structural Members ◽  
Load Case ◽  
Portal Frame ◽  
Parametric Optimization Problem

The paper has proposed a mathematical model for parametric optimization problem of the steel lattice portal frame. The design variable vector includes geometrical parameters of the structure (node coordinates), as well as cross-sectional dimensions of the structural members. The system of constraints covers load-carrying capacities constraints formulated for all design sections of structural members of the steel structure subjected to all ultimate load case combinations. The displacements constraints formulated for the specifiednodes of the steel structure subjected to all serviceability load case combinations have been also included into the system of constraints. Additional requirements in the form of constraints on lower and upper values of the design variables, constraints on permissible minimal thicknesses, constraints on permissible maximum diameter-to-thickness ratio for the structural members with circle hollow sections, as well as the conditions for designing gusset-less welded joints between structural members with circle hollow sections have been also considered in the scope of the mathematical model. The method of the objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations has been used to solve the formulated parametric optimization problem. New optimal layouts of the steel lattice portal frame by the criterion of the minimum weight, as well as minimum costs on manufacturing and erection have been presented.

scholarly journals Experimental Study on the Behavior of Tension Member Under Rupture

2021 ◽  
Keyword(s):  
Experimental Study ◽  
Tensile Force ◽  
Steel Structure ◽  
Steel Structures ◽  
Structural Members ◽  
Steel Members ◽  
Tension Member ◽  
Strong Relation ◽  
Almost All ◽  
Tension Members

Abstract. A steel structure is naturally lighter than a comparable concrete construction because of the higher strength and firmness of steel. Nowadays, the growth of steel structures in India is enormous. There are so many advantages in adopting the steel as structural members. Almost all high-rise buildings, warehouses & go-downs are steel structures and even some of the commercial buildings are made of steel. Tension members are the elements that are subjected to direct axial load which tends in the elongation of the structural members. Even today bolted connections play a major role in the connection of hot rolled structural steel members. In this experimental study the behavior of tension members (TM) such as plates, angles & channels have been studied under axial tensile force. There is strong relation between pitch and gauge (with in the specified limit as per IS 800:2007) in determining the rupture failure plane. In this study we intensively tested the behaviour of TM for different fasteners pattern by changing the pitch, gauge, end & edge distance and by adopting the different patterns or arrangements of bolted connection in it.

Experimental Study on Seismic Behaviors of Improved Composite Steel Staggered Truss Structures

2012 ◽  
Vol 166-169 ◽  
pp. 1383-1386
Author(s):  
Hong Dong Ran ◽  
Wen Xv ◽  
Ming Zhou Su
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Failure Mechanism ◽  
Stress Measurement ◽  
Plastic Hinge ◽  
Steel Structure ◽  
Steel Structures ◽  
Hysteretic Behavior ◽  
Truss Structures ◽  
Seismic Behaviors

According to the poorly seismic behaviors of composite staggered trusses system, an improved composite staggered trusses system was proposed. Based on the experimental study of a 1/3 scale improved composite staggered truss frame steel structure model under cyclic loading, the seismic behaviors and failure mechanism was studied, and the seismic behaviors was evaluated by the hysteretic behavior, ductility, energy dissipation and rigidity degeneration. The study showed that the improved composite staggered truss steel structures had the advantages in bearing capacity, ductility, deformability and energy dissipation, but the lateral rigidity was weak and non-uniform along its vertical layout. The stress measurement showed that the plastic hinge formed in the web members of the truss firstly, then, in the chord members of the truss, and finally the plastic hinges formed in the column, earthquake energy mostly dissipated by the truss members, the failure mechanism of the improved composite staggered truss steel structures was the beam hinges failure mechanism.

scholarly journals Size optimization of single edge folds for cold-formed structural members

2020 ◽  
pp. 73-86
Author(s):  
Serhii Bilyk ◽  
Vitalina Yurchenko
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Optimization Problem ◽  
Parametric Optimization ◽  
Optimization Problems ◽  
Structural Members ◽  
Single Edge ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Parametric Optimization Problem

Parametric optimization problem for single edge fold size in cold-formed structural members subjected to central compression has been considered by the paper. Determination the load-bearing capacity of the cold-formed structural members has been performed using the geometrical properties calculated based on the constructed “effective” (reduced) cross-sections taking into account local buckling effects in the section as well as distortional buckling effects. Single edge fold size in cold-formed C-profile has been considered as design variable. Linear convolution of criteria, namely minimization criterion of design area of stiffener cross-section and maximization criterion effective area of stiffener cross-section which defines it reduced load-bearing capacity due to flexural buckling has been used as optimization criterion. The parametric optimization problem has been solved using the method of objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations. In order to realize the formulated optimization problem, software OptCAD intended to solve parametric optimization problems for steel structural systems has been used. Optimization results of the single edge folds for the cold-formed С-profiles manufactured by «Blachy Pruszyński» company, «BF FACTORY» company as well as «STEELCO» company have been presented by the paper. The results of the performed investigation can be used as recommendations for companies-manufacturers of the cold-formed profiles, as well as a guide for creation the national assortment base of the effective cold-formed profiles promoting wider implementation of cold-formed steel structures in building practice.

scholarly journals Optimal numbers of the redundant members for introducing initial pre-stressing forces into steel bar structures

2021 ◽  
pp. 68-91
Author(s):  
Vitalina Yurchenko ◽  
Ivan Peleshko
Keyword(s):  
Parametric Optimization ◽  
Optimization Problems ◽  
Numerical Technique ◽  
Limit State ◽  
Optimal Number ◽  
Ultimate Limit State ◽  
Structural Members ◽  
Cross Sectional ◽  
Design Load ◽  
Steel Bar

The paper considers parametric optimization problems for the steel bar structures formulated as nonlinear programming ones with variable unknown cross-sectional sizes of the structural members, as well as initial prestressing forces introduced into the specified redundant members of the structure. The system of constraints covers load-bearing capacity constraints for all the design sections of the structural members subjected to all the design load combinations at ultimate limit state, as well as displacement constraints for the specified nodes of the bar system, subjected to all design load combinations at serviceability limit state. The method of the objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations has been used to solve the parametric optimization problem. A numerical technique to determine the optimal number of the redundant members to introduce the initial prestressing forces has been offered for high-order statically indeterminate bar structures. It reduces the dimension for the design variable vector of unknown initial prestressing forces for considered optimization problems.

scholarly journals Parametric optimization of magnetoelectric generator with double stator

2021 ◽  
pp. 33-38
Author(s):  
Anna Lykhohub ◽  
Mykhayl Kovalenko ◽  
Igor Tkachuk ◽  
Anton Goncharyk
Keyword(s):  
Permanent Magnet ◽  
Computer Aided Design ◽  
Parametric Optimization ◽  
Geometric Model ◽  
Geometric Parameters ◽  
Design System ◽  
Geometrical Parameters ◽  
Structural Element ◽  
Axial Flux ◽  
Permanent Magnet Generator

A methodology for the optimization-parametric calculation of geometric parameters of the design of an axial-flux permanent magnet generator has been developed. The developed methodology can be used to calculate and optimize geometric parameters in an automated mode for almost any type of electromechanical energy converter. The operation of the developed system is based on the interconnections between the computer-aided design system, software package, and numerical calculation of the electromagnetic field with the possibility of feedback and parameterization and a computing environment such as Matlab. The parameterized geometric model is constructed on the example of an axial-flux permanent magnet generator with a double stator. Subsequently, parametric optimization of geometric parameters was performed using the developed algorithm. The use of the developed solution reduces the time spent by the researcher on the calculation of geometry and optimization. Parameterization is performed at all stages of construction of a single part, the geometry of which is planned to change, and in each part of the assemblies if any in a particular case. That is, with the help of the developed model, it is possible to program the optimization of both a separate structural element of the studied system and the object as a whole. In the process of optimization, the main geometrical parameters of the investigated end generator with double side changed: stator yoke, air gap, gear-groove zone of the stator, housing elements. As a result of parametric optimization of the geometry of the prototype, it was possible to reduce the geometric dimensions by optimizing the magnitude of the magnetic induction in some areas of the magnetic core of the studied generator. Due to the application of the developed algorithm, it was possible to reduce the cost of the generator, as well as the volume of the magnetic circuit by 18.1% and 24.3%, respectively. This indicates the effectiveness of the developed algorithm and the possibility of using this algorithm in further research

scholarly journals Analysis of the load-carrying capacity of a steel frame under fire conditions

2018 ◽  
Vol 187 (1) ◽  
pp. 129-139
Author(s):  
Piotr Bilko ◽  
Szymon Sawczynski
Keyword(s):  
Stress Analysis ◽  
Carrying Capacity ◽  
Steel Structure ◽  
Steel Structures ◽  
Load Carrying Capacity ◽  
Structural Members ◽  
Basic Principles ◽  
Load Carrying ◽  
Strain Stress ◽  
Fire Conditions

This article aims at presenting the basic principles of designing steel structures according to Eurocode PN-EN 1993-1-2, i.e. with respect to ensuring the appropriate level of safety for such structures in case of a fire developing into flashover. The load-carrying capacity of a steel structure, serving as an example, was assessed on the basis of a static strain-stress analysis. The analysis was conducted regarding changes in the temperature of structural members, both the exposed and the fireproof protected ones, under fire conditions.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

scholarly journals R-Regularity of Set-Valued Mappings Under the Relaxed Constant Positive Linear Dependence Constraint Qualification with Applications to Parametric and Bilevel Optimization

2021 ◽  
Author(s):  
Patrick Mehlitz ◽  
Leonid I. Minchenko
Keyword(s):  
Linear Dependence ◽  
Constraint Qualification ◽  
Parametric Optimization ◽  
Optimization Problems ◽  
Sufficient Conditions ◽  
Bilevel Optimization ◽  
Regularity Property ◽  
Constant Rank Constraint Qualification ◽  
Existence Criterion ◽  
Set Valued Mappings

AbstractThe presence of Lipschitzian properties for solution mappings associated with nonlinear parametric optimization problems is desirable in the context of, e.g., stability analysis or bilevel optimization. An example of such a Lipschitzian property for set-valued mappings, whose graph is the solution set of a system of nonlinear inequalities and equations, is R-regularity. Based on the so-called relaxed constant positive linear dependence constraint qualification, we provide a criterion ensuring the presence of the R-regularity property. In this regard, our analysis generalizes earlier results of that type which exploited the stronger Mangasarian–Fromovitz or constant rank constraint qualification. Afterwards, we apply our findings in order to derive new sufficient conditions which guarantee the presence of R-regularity for solution mappings in parametric optimization. Finally, our results are used to derive an existence criterion for solutions in pessimistic bilevel optimization and a sufficient condition for the presence of the so-called partial calmness property in optimistic bilevel optimization.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

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