Jib portal krenin tasarımı ve sonlu elemanlar metoduna göre analizi
Design of a jib portal crane and analysis with finite element method
Yazar: FEYYAZ AYDEMİR
Danışman: DOÇ. DR. SERPİL KURT HABİBOĞLU
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Konstrüksiyon Bilim Dalı
Derece: Yüksek Lisans, 2017
Konu: Makine Mühendisliği = Mechanical Engineering

Özet:
Jib Portal Krenler, raylı sistemler üzerinde ileri geri hareket edebilen aynı zamanda üzerinde bulunan oklu döner kren aksamlarıyla yükü üç doğrultuda da kaldırıp taşıyabilen; tersanelerde, limanlarda, açık denizlerde, petrol ve doğalgaz sahalarında, gemilerin imalatında, inşaat şantiyelerinde sıklıkla kullanılan bir kren çeşididir. Jib Portal Krenler, portal krenler ile oklu döner krenlerin fiziksel ve mekanik özelliklerini birarada barındırdığı için bu krenlerin birleşimi olarak değerlendirilebilir. 
Bu tez çalışmamızda 40 m x 10 ton maksimum moment taşıma kapasiteli, en fazla 25 ton yük taşıyabilen jib portal krenimizin FEM ve DIN standartlarına bağlı olarak işletme grubu belirlenmiş, analitik olarak statik yük hesapları yapılmış, statik yük hesapları neticesinde krenimizin emniyetli olduğu anlaşıldıktan sonra Solidworks bilgisayar destekli tasarım (CAD) programı aracılığıyla katı modeli oluşturularak tasarımı yapılmış ve son aşamada da oluşturulan katı model, analiz programına aktarılarak Ansys Workbench analiz programı aracılığıyla jib portal krenimizin boomunda (ok) meydana gelen sehim ve gerilmelerin analizleri yapılmıştır. 
Jib Portal Krenimiz, tasarlanmadan önce FEM ve DIN normlarına göre kaldırma makinesi, çalışma süresi, yük dağılımı, yükleme durumu göz önünde bulundurularak sınıflandırılır ve bunun neticesinde tablolar aracılığıyla krenin işletme grubu belirlenir. Krenin işletme gurubu belirlendikten sonra ekipmanlarının boyutlandırılması ve sistemin emniyetli olup olmadığının irdelenmesi için jib portal krenimiz, analitik olarak statik yük hesaplamalarına tabi tutulmuştur. Bir krene çalışması esnasında kendi zati ağırlığı, taşıdığı yük ağırlığı, rüzgar, ivmelenme, frenleme ve ataletten gelen yükler etkir. Bu tez çalışmamızda sadece jib portal krenimize etkiyen statik yükler (kren zati ağırlığı, taşıma yükü) göz önünde bulundurularak krenimizin statik yük hesaplamaları ve analizleri yapılmış olup; rüzgar, ivmelenme, frenleme ve ataletten gelen dinamik yükler ihmal edilmiştir. Analitik olarak yapılan statik yük hesaplamaları sonucunda jib portal krenimizde bulunan ok çekme ve yük kaldırma vinç elemanları olan halat, tambur, makara çapları ve motor güçleri ile kren yürütme sistemi elemanları olan avare ve tahrikli tekerleklerinin çapları ve motor güçleri hesaplanarak jib portal krenimizin elemanları boyutlandırılmıştır. Bunların yanında yük taşıma elemanı olarak krenimizde kullanılan, kafes konstrüksiyona sahip boomda (ok), kendi zati ağırlığı ve taşıdığı yük ve halat kuvvetlerinin etkisiyle meydana gelen sehim ve gerilmeler hesaplanmıştır. Jib Portal Krenimizin malzemesi "St37" yapı çeliği olarak seçilmiş olup, yapılan statik yük hesaplamaları sonucunda sistemin emniyetli olduğu anlaşılmıştır.  
Jib Portal Krenimizin emniyetli olduğu anlaşıldıktan ve ekipmanlarının boyutları çıkartıldıktan sonra, tasarım aşamasına geçilmiştir. Solidworks CAD programı aracılığıyla bütün kren ekipmanları modellenip daha sonra birbirlerine montajlanarak Jib Portal Krenimizin modeli oluşturulmuştur. Krenimizin statik yük hesapları neticesinde tasarımı aşamasında; konstrüksiyonun hafif ve emniyetli olması, mukavemetinin yüksek olması, montaj ve üretim kolaylığı, işçilik süresi ve maliyeti gözönünde bulundurularak en uygun şartlarda tasarım yapılmaya çalışılmıştır.
Krenimizin katı model hali "Step" dosyası formatında kaydedilerek Sonlu Elemanlar Metoduyla statik analiz yapılmak üzere Ansys Worksbench programına aktarılmıştır.
Sonlu Elemanlar Metodu kullanılarak Ansys Workbench programı aracılığıyla konstrüksiyonun geometik modeli, malzemesi atanır. Daha sonra model üzerinde mafsal noktaları, yer çekimi ve booma etkiyen kuvvetler tanımlanarak modelin sınır şartları belirlenir. Modelin matematiksel olarak daha hassas incelenmesi için model kendinden daha küçük alt parçalara bölünür. Meshleme adını verdiğimiz bu işlem yapıldıktan sonra model çözümlenir. Modelin çözümlenmesiyle birlikte boomda meydana gelen sehim ve gerilmeler (Von Mises) elde edilir.
Son bölümde ise analitik olarak elde edilen sehim ve gerilme değerleri ile Ansys Workbench programında elde edilen değerler karşılaştırılır. Sonuçların arasındaki farkın %10'dan fazla olmaması göz önünde bulundurularak eşleştirilmesi sağlanır.

Abstract:
Cranes are lifting machines in transport system which provides the load's lifting and transfer in shipyards, seaports, ware houses, heavy machinery industry and construction sites. Cranes are transport machines such as elevator, conveyor, escalator, which are used for transportation of persons and loads. The most known and the most frequently used cranes are cable cranes, tower cranes, mobile cranes, gantry cranes and bridge cranes.
Within this thesis study, a Jib Portal Crane was designed and analysed. Jib Portal Cranes are transport machines which move on the rail systems like the gantry cranes and used to lift and transfer the load in every desired directions with the turntable and jointed boom to the turntable like the tower cranes. Therefore, jib portal cranes can be thought as a combination of gantry and tower cranes with their similar physical and mechanical properties. Jib Portal Cranes are frequently used in shipyards, seaports, off-shore petroleum and natural gas platforms, processing facilities, warehouses and construction sites. 
In this study, a Jib Portal Crane which has 10 tons load capacity at 40 meters boom radius (maximum 400 Tons.m load moment capacity) and can lift maximum 25 tons load was classified, designed and analysed by using analytically static load calculations and finite element method. Firstly, Jib Portal Crane was classified according to its usage, loading, operating time and load distribution by taking FEM and DIN Standards into consideration. After it was classified, Jib Portal Crane's static load calculations were made analytically before it has been designed. The material was selected "St 37" steel. In static load calculations, the load, the boom's self-weight and the rope forces which act to the boom were taken into consideration and the deflection and stresses which occurred on the boom were calculated. As a result of these calculations, the system's safety was checked and all the jib portal crane equipment's dimensions were specified. In the next process, Jib Portal Crane was designed with all the equipment by using Solidworks 3D CAD program. After design process, crane's model file was transferred to Ansys Workbench program to be analysed for static structural by using Finite Element Method. The deflection and stresses (Von Mises) which occurred on the boom were seen on the computer screen by using Ansys Workbench program. The deflection and stress values which were obtained analytically and by using finite element method were compared to check if the results were similar. It has been seen that the results were similar and less than %10 difference between the results.
In the second chapter, jib portal crane's equipments were explained with their figures. A Jib Portal Crane consists of idler and driven wheels, bogie groups, legs, main portal frame, cylindrical frame, turntable, operator's cabin, engine room, counterweight, lattice girder and boom. In our crane, totally 16 pieces Ø400 mm (8 of them are driven) wheels are used. Wheels were assembled to the bogie groups. Bogie groups hold the wheels together and every bogie group has two wheels (one of them is driven and another one is idler). In this crane; totally 8 pieces bogie groups were used to hold the wheels together. Bogie groups were connected to the legs by pins. Legs are at the left and right undersides of the jib portal cranes. Main Portal Frame is assembled between the legs and cylindrical frame. Main Portal Frame is exposed to deflection and bending stresses because of the self-weight and weight of the parts which placed on it. Cylindrical frame is assembled to the turntable. Turntable can revolve 360° around cylindrical frame. Engine room, operator's cabin, lattice girder, counter-weight and boom are on the turntable. In engine room, there are the lifting equipment for the load and the boom. The lifting equipment consists of driven group (electrical motor, gear box), gear, drum, steel wire rope and pulley. One of these lifting equipment controls the load's movement and other one controls the boom's movement by steel wire ropes. Both of the boom and lattice girder are connected to the turntable at the joints by pins.
In third chapter, Jib Portal Crane was classified according to FEM and DIN Standards for crane's usage, loading, load distribution and operating time. Minimum safety coefficient "Zp", coefficient of amplification "ϒc", lift coefficient "ψ" and "h1" coefficients for the calculations of ropes, drums and pulleys were specified by using the tables after our crane's classification was specified. These coefficients are required for jib portal crane's static load calculations. The material was selected "St 37" steel for Jib Portal Crane.
In fourth chapter, static load calculations were made analytically to check the system's safety, strength of the material (St 37 steel) and obtain the all the crane equipment's dimensions and electric motor powers. Before starting static load calculations, firstly boom's section was selected as the square. It is decided that boom's construction was selected lattice beam to reduce the wind force's effects to minimum. Boom consists of four main beams which were exposed to load and support beams which hold the main beams together and don't carry loads. While main beams were selected 150x150x10 mm square profiles, support beams were selected Ø88.9x3.2 mm pipe profiles. Pipe profiles have higher strength in comparison to box profiles for wind forces because they are exposed to wind forces less due to their geometric shapes. Stress concentration is not occurred on pipe profiles but it is occurred on box profiles. For this reason, support beams were selected as pipe section. On the other hand, main profiles were selected as square profiles for easy weldability to pipe profiles. Support pipe profile beams were welded to main beams to hold the main square profile beams together. During the boom's construction was selected, it was preferred that the construction was lightweight, high strength and weldability. Boom's construction was specified and boom's weight was calculated. Nevertheless, counterweight and crane's self-weight were specified. After these weights were specified, static load calculations can be introduced.
In static load calculations, balancing and overturning moments are calculated by using static controlling factor, load, boom's weight, jib crane's light weight and counter-weight and it has seen that balancing moment was bigger than overturning moment. This situation indicates that the system has been safe so that not to be overturned. Jib portal crane is affected by load, self-weight, wind force, inertial force and acceleration and braking forces. Within this thesis study, only static forces (load and self-weight) which affect to boom are analysed and dynamic forces (wind, inertial, acceleration and braking forces) are neglected. Within these calculations; rope, grooved drum and pulley diameters and electrical motor powers were calculated by using coefficients which specified in third chapter. Ropes, drums, pulleys and electrical motors are the elements of lifting equipment for load and boom. 55 Kw, 3 phases, 4 poles, 1480 rpm electrical motor was selected for lifting the boom and 45 Kw, 3 phases, 4 poles, 1480 rpm electrical motor was selected for lifting the load.
For the idler and driven wheels, the diameter and electrical motor powers were calculated. In this system, 8 pieces 2.20 kw motor and 16 pieces Ø400 mm wheels are used. For design process, the dimensions of bogie groups, legs, main portal frame, cylindrical frame and other equipment were obtained. As a result of the boom self-weight and load's effects, deflection which occurred on the middle section of boom and stresses which occurred on the bottom and top section of boom were calculated analytically. It was determined that system has been safe for strength of St37 material. After static load calculations were completed, the design process starts.
In Design Process, SolidWorks 3D Cad program was used to design a jib portal crane model. Ease of manufacturing, mount ability, weldability, employment and material cost, lightweight construction and high strength are taken into consideration as the most important factors to obtain the optimum design. Firstly, all jib portal crane equipments were drawn by using their dimensions which were obtained as a result of static load calculations. After these equipments were designed, these equipments were assembled to each other. As a result of this assembly, jib portal crane model was created. Jib portal crane's model was saved as the "Step" file and transferred to Ansys Workbench program to be analysed as the static structural by using Finite Element Method.  
In fifth chapter, Finite Element Method and Ansys Workbench analysing program were mentioned. It was given information about this method and program's usage. Finite Element Method is used to solve and analyse the complicated geometric systems easily. In Finite Element Method, the model is divided into the simple finite elements for easy solution. System's boundary conditions are defined and model is solved. As a result of this solution, the deformations and stresses which occur on the model are obtained. Ansys Workbench software is one of the analysing programs which Finite Element Method was used. 
In Ansys Workbench program, the boom was analysed as static structural to obtain the deflection and stresses (Von Mises) which occur on the boom.  When the Ansys page was opened, firstly the analysing type was selected as "Static Structural". The material of the system was defined as "St 37" steel in "Engineering Data" box. The boom model which was saved as "Step" file was transferred to "Geometry" box to define the geometry of model. After these processes, "Model" screen was opened. In "Model" screen, the joint points of the boom, gravity and static forces which affects to the boom were defined as the boundary conditions of the boom. Boom was divided into several finite elements to obtain easy solution by using "Mesh" command. After it was solved, the deflection and stress (Von Mises) values which occur on the boom were seen by the colour graphics on the screen.  
In the last chapter, the deflection and stress values which were obtained by analytical calculations and obtained by using Finite Element Method were compared to check the reliability of Finite Element Method for Jib Portal Crane's static structural analysing. The difference should be less than %10 to be accepted that the results were similar. In conclusion, it has been seen that the deflection and stress values were similar for finite element method and analytical calculations.