Ondülin Gövdeli Kirişlerin Stokastik Optimizasyon Yöntemleri Kullanılarak Optimum Boyutlandırılması

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Gövde kesiti ince dalgalı çelik bir levhanın alt ve üst flanş görevi gören iki çelik plaka ile birleştirilmesi şeklinde tasarlanan ondülin gövdeli kirişler stabilite kaybına ve deformasyonlara engel olurken, yük altında kirişin plastik limit noktasına gelmeden rijitlik kaybına bağlı burkulmasını engelleyerek kesme kuvvetine ve yerel etkilere karşı kirişin yük taşıma kapasitesini arttırmaktadır. Kiriş gövdesinin bu özel yapısı ile kiriş öz ağırlığının azalması ve yük taşıma kapasitesinin artması sağlanarak ekonomik kazanç elde edilmektedir. Bu çalışmada, dalgalı gövde yapısına ait kalınlık ve derinlik parametreleri ile flanşların kalınlıkları tasarım değişkenleri olarak alınarak ondülin gövdeli kirişlerin yeni optimizasyon yöntemleri ile tasarım sınırlayıcıları altında minimum ağırlığa sahip olacak şekilde optimum boyutlandırılması yapılacaktır. Formülasyonu oluşturulmuş yapısal optimizayon problemlerinin çözümü yeni optimizasyon teknikleri olan av arama ve ateşböceği algoritması yöntemlerinin adaptasyonu ile elde edilecek ve bu şekilde aynı zamanda bu stokastik yöntemlerin yapıya ilk uyarlamaları gerçekleştirilerek her iki yöntemin minimum ağırlığının bulunması sürecinde sergilediği performanslar kıyaslanacaktır. Ondülin gövdeli çelik kiriş sistemlerinin tasarımları için BS EN1993-1:2005 (Annex-D, Eurocode 3) ve DIN 18-800 Teil-1 şartnamelerinde öngörülen tasarım kıstasları esas olarak kabul edilecektir. Anahtar Kelimeler: Stokastik Methodlar, Av Arama, Ateş Böceği Algoritması, Ondülin Gövdeli Kirişler.Corrugated structure of the web cross-section not only increases the resistance of the beam against to shear force and other possible local effects, but also prevents the buckling due to loss of moment of inertia before the plastic limit. This specific structure of the web leads to a decrease in the beam unit weight and increase in the load carrying capacity. In this study, corrugated web beams will be optimized by use of stochastic optimization methods. Web height, web thickness, distance between the peaks of the following two web curves as well as the width and thickness of flange of corrugated beam will be considered as the problem design variables. Optimum design problems, formulations of which are obtained depending on the shape of beams, will be solved with three new optimization methods namely hunting search and firefly algorithm. A number of design examples will be carried out and performances of each method in finding the minimum weight of built-up beams will be compared. Design restrictions for corrugated web beams will be taken from BS EN1993-1:2005 (Annex-D, Eurocode 3) and DIN 18-800 Teil-1. Key words: Stochastic methods, Hunting Search, Fire Fly Algorithm, Corrugated Web Beam

Triboelektrična i hidrofobna svojstva funkcionaliziranih lignoceluloznih materijala

In the development of sustainable products, lignocellulosic materials with hydrophobic properties can be functionalized and used as reinforcement, especially in bio-composite materials, as well as in various applications such as packaging, water-repellent and self-renewing materials. This study is aimed to improve the surface properties and triboelectric properties of wood materials. Functionalized wood veneers were prepared by impregnating 3 different wood veneers (beech, mahogany and oak) with 5 different chemical solutions (cationic cellulose, cationic starch, polyethyleneimine, sodium alginate and carboxymethyl cellulose). Structural characterization of the functional wood materials obtained was investigated by Fourier-transform infrared spectroscopy (FT-IR) technique, wettability and surface properties were examined by contact angle measurements, and morphological properties were examined by scanning electron microscopy (SEM). The triboelectric properties of the devices prepared using functionalized wood materials were investigated. As a result, it was determined that the hydrophobic properties of wood materials were improved and showed triboelectric properties. It demonstrates that functionalized wood materials can be used to power low-power electronic devices.U razvoju održivih proizvoda lignocelulozni materijali hidrofobnih svojstava mogu se funkcionalizirati i upotrebljavati kao ojačivači u biokompozitnim materijalima ili mogu imati različitu primjenu u ambalaži te u vodoodbojnim i samoobnavljajućim materijalima. Cilj ovog istraživanja bio je pronaći način poboljšanja površinskih i triboelektričnih svojstava drvnih materijala. Za istraživanje je pripremljen funkcionalizirani furnir od tri različite vrste drva (bukovine, mahagonija i hrastovine), impregniran s pet različitih kemijskih otopina (kationskom celulozom, kationskim škrobom, polietileniminom, natrijevim alginatom i karboksimetilcelulozom). Karakterizacija strukture dobivenih funkcionaliziranih drvnih materijala provedena je Furierovom infracrvenom spektroskopijom (FT-IR), kvašenje i svojstva površine istražena su mjerenjem kontaktnog kuta, a morfološka svojstva ispitana su skenirajućim elektronskim mikroskopom (SEM). Nadalje, istražena su triboelektrična svojstva uređaja izrađenih od funkcionaliziranih drvnih materijala. Utvrđeno je da se funkcionalizirani drvni materijali mogu primijeniti za napajanje uređaja male snage

Structural features of cold-formed steel profiles

Using capacity of cold-formed steel sections increases thanks to the opportunities which are offered by the developing technology. Low production cost and variety of profiles that can be produce easy, fast, high quality provide to improve its popularity as a structural material. In production, Sulphur and Phosphorous accumulation region occurs at intersection region of flanges and web of hot rolled steel profile. This causes to decrease strength of profile. Other difference between cold-formed and hot rolled steel sections is that mechanical properties of steel material homogeneously distributes throughout the profile. Both in frame and truss systems, cold-formed steel profiles develop both as main and secondary bearing element. These present variety options to the designers with pure, galvanized, aluminized applications. As with many building materials, mechanical behavior of cold-formed steel profile is quite complex due to the nature of thin walled steel sections. Design and analysis methods of cold-formed steel profile are rapidly shaped day by day. The general theory of beams investigated in past studies make possible analyses of cold-formed steel profile. Moreover, in structural systems, using of cold-formed steel profile provide height strength besides sustainable, environmentalist, green building because it requires less material and cost. Although these profiles have many advantages, use of cold-formed steel profiles in our country structures is rather limited unfortunately. New steel construction regulations in Turkey also do not mention cold-formed thin walled steel structure. Main purpose of this study reviews structural specifications of cold-formed steel profiles which are applied world-wide

THE EFFECT OF MEMBER GROUPING ON THE OPTIMUM DESIGN OF GRILLAGES VIA SEARCH TECHNIQUES

Member grouping of a steel grillage system has an important effect in the minimum weight design of these systems. In the present research, this effect is investigated using an optimum design algorithm which is based on two stochastic search techniques called particle swarm (PSO) and harmony search (HS) optimization methods. The optimum design problem of a grillage system is formulated by implementing LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Construction) limitations. It is decided that W-Sections are to be adapted for the longitudinal and transverse beams of the grillage system. 272 W-Section beams given in LRFD code are collected in a pool and the optimum design algorithm is expected to select the appropriate sections from this pool so that the weight of the grillage is the minimum correspondingly the design limitations implemented from the design code are satisfied. The solution for this discrete programming problem is determined by using the PSO and HS algorithms. Design example is presented to demonstrate the effect of beam spacing and performances of stochastic search techniques in the optimum design of grillage systems

Izgara sistemlerinin harmoni arama yöntemi kullanılarak optimum boyutlandırılması.

Harmony search method based optimum design algorithm is presented for the grillage systems. This numerical optimization technique imitates the musical performance process that takes place when a musician searches for a better state of harmony. For instance, jazz improvisation seeks to find musically pleasing harmony similar to the optimum design process which seeks to find the optimum solution. The design algorithm considers the displacement and strength constraints which are implemented from LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Construction). It selects the appropriate W (Wide Flange)-sections for the transverse and longitudinal beams of the grillage system among 272 discrete W-section designations given in LRFD-AISC so that the design limitations described in LRFD are satisfied and the weight of the system is confined to be minimal. Number of design examples is considered to demonstrate the efficiency of the algorithm presented.M.S. - Master of Scienc

Optimum boyutlandırılmış dairesel gözenekli petek kirişlerin yük taşıma kapasitesi.

Cellular beams became increasingly popular as an efficient structural form in steel construction since their introduction. Their sophisticated design and profiling process provides greater flexibility in beam proportioning for strength, depth, size and location of circular holes. The purpose of manufacturing these beams is to increase overall beam depth, the moment of inertia and section modulus, which results in greater strength and rigidity. Cellular beams are used as primary or secondary floor beams in order to achieve long spans and service integration. They are also used as roof beams beyond the range of portal-frame construction, and are the perfect solution for curved roof applications, combining weight savings with a low-cost manufacturing process. The purpose of the current research is to study optimum design, ultimate load capacity under applied load and finite element analysis of non-composite cellular beams. The first part of the research program focuses on the optimum design of steel cellular beams using one of the stochastic search methods called “harmony search algorithm”. The minimum weight is taken as the design objective while the design constraints are implemented from the Steel Construction Institute. Design constraints include the displacement limitations, overall beam flexural capacity, beam shear capacity, overall beam buckling strength, web post flexure and buckling, vierendeel bending of upper and lower tees and local buckling of compression flange. The design methods adopted in this publication are consistent with BS5950. In the second part of the research, which is the experimental work, twelve non-composite cellular beams are tested to determine the ultimate load carrying capacities of these beams under using a hydraulic plug to apply point load. The tested cellular beam specimens have been designed by using harmony search algorithm. Finally, finite element analysis program is used to perform elastic buckling analysis and predict critical loads of all steel cellular beams. Finite element analysis results are then compared with experimental test results for each tested cellular beam.Ph.D. - Doctoral Progra

Harmony search based algorithm for the optimum design of grillage systems to LRFD-AISC

Harmony search based optimum design method is presented for the grillage systems. This numerical technique imitates the musical performance process that takes place when a musician searches for a better state of harmony. Jazz improvisation seeks to find musically pleasing harmony similar to the optimum design process which seeks to find the optimum solution. The design algorithm considers the serviceability and ultimate strength constraints which are implemented from Load and Resistance Factor Design-American Institute of Steel Construction (LRFD-AISC). It selects the appropriate W-sections for the transverse and longitudinal beams of the grillage system out of 272 discrete W-section designations given in LRFD-AISC. This selection is carried out such that the design limitations described in LRFD-AISC are satisfied and the weight of the system is the minimum. Many design examples are considered to demonstrate the efficiency of the algorithm presented

Experimental investigation and numerical analysis of optimally designed composite beams with corrugated steel webs

WOS:000580565300001Composite beams with corrugated steel webs represent a new innovative system which has emerged in the past decade for medium span in the construction technology. The use of composite beams with corrugated steel webs results in a range of benefits, including flexible spaces and reduced foundation costs in the construction technology. The thin corrugated web affords a significant weight reduction of these beams, compared with hot-rolled or welded ones. In the current research, an optimal designed I-girder beam with corrugated web has been proposed to improve the structural performance of continuous composite girder under bending moment. The experimental program has been conducted for six simply supported composite beams with different loading conditions. The tested specimens are designed by using one of the stochastic techniques called hunting search algorithm. In the optimization process, besides the thickness of concrete slab and studs, corrugated web properties are considered as design variables. The design constraints are respectively implemented from Eurocode 3, BS-8110 and DIN 18-800 Teil-1. The last part of the study focuses on performing a numerical study on composite beams by utilizing finite element analysis and the bending behavior of steel girders with corrugated webs experimentally and numerically verified the results. A nonlinear analysis was carried out using the finite element software ANSYS on the composite beams which were modelled using the elements ten-node high order quadrilateral type.This paper is partially based on researches supported by the Akdeniz University Research Funding (FBA-2018-3668) and Scientific Research Council of Turkey TUBITAK Research Grant No: 213M656) which are gratefully acknowledged

Optimum Design of Composite Corrugated Web Beams Using Hunting Search Algorithm

Over the past few years there has been sustainable development in the steel and composite construction technology. One of the recent additions to such developments is the I-girders with corrugated web beams. The use of these new generation beams results in a range of benefits, including flexible, free internal spaces and reduced foundation costs. Corrugated web beams are built-up girders with a thin-walled, corrugated web and wide plate flanges. The thin corrugated web affords a significant weight reduction of these beams, compared with hot-rolled or welded ones. In this paper, optimum design of corrugated composite beams is presented. A recent stochastic optimization algorithm coded that is based on hunting search is used for obtaining the solution of the design problem. In the optimisation process, besides the thickness of concrete slab and studs, web height and thickness, distance between the peaks of the two curves, the width and thickness of flange are considered as design variables. The design constraints are respectively implemented from BS EN1993-1:2005 (Annex-D, Eurocode 3) BS-8110 and DIN 18-800 Teil-1. Furthermore, these selections are also carried out such that the design limitations are satisfied and the weight of the composite corrugated web beam is the minimum

Nonlinear finite element analysis of optimally designed steel cellular beams

Cellular beams became increasingly popular as an efficient structural form in steel construction since their introduction. Their sophisticated design and profiling process provides greater flexibility in beam proportioning for strength, depth, size and location of circular holes. The purpose of manufacturing these beams is to increase the overall beam depth, the moment of inertia and section modulus, which results in greater strength and rigidity. The objective of this study is to carry out non-linear finite element (FE) analysis of the cellular beams that were considered in the experimental study in order to determine their ultimate load carrying capacity for comparison. The finite element method has been used to predict their entire response to increasing values of external loading until they lose their load carrying capacity. FE model of each specimen that is utilized in the experimental studies is carried out. FE models of steel cellular beams are used to simulate the experimental work to verify of test results and to investigate the non-linear behavior of failure modes such as web-post buckling, shear buckling and vierendeel bending of beams