Maden kulesi ve asansörü sonlu elemanlar ile analizi
Head frame and elevator analysis with finite element
Yazar: METİN ALTUN
Danışman: YRD. DOÇ. DR. İSMAİL GERDEMELİ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Konstrüksiyon Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Maden Mühendisliği ve Madencilik = Mining Engineering and Mining ; Makine Mühendisliği = Mechanical Engineering

Özet:
Bu tezde bir maden kulesinin dizaynının nasıl yapıldığına ilişkin temel bilgileri bulabilirsiniz. Öncelikle temel elemanları ve görevleri tanımlanmış, ardından da maden kulesinin nasıl boyutlandırılması gerektiği açıklanmıştır. Kule ayak eksenlerinin nasıl tespit edildiği ve maden çıkarma moletlerinin hangi prensiple çalıştığı denklemleriyle anlatılmıştır. Maden kulesinin ne kadar cevher çıkaracağı ile ilgili asansör ve kafes hesapları yapılmış, hız zaman diagramı şema gösterimi ile anlatılmıştır. Kule ayak kesit alanının nasıl hesaplandığı ve bu hesap kullanılarak kule ayak saçlarının nasıl tespit edildiği açıklanmıştır. Bu kısımda gerçek bir kule ayak kesit alanı çizimi de gösterilmiştir.
Tezin ikinci kısmında Solidworks programı ile modellenen kule Ansys programına alınmış, burada üç tip mesh elemanı kullanarak mesh edilmiş ve bütün parçaların kuvvet akışlarını düzgün olarak iletebilmesi için birbiri ile düzgün bir mesh geçişine sahip olması sağlanmıştır. Sınır koşulları tanıtılmış, modele gelen kuvvetler altı farklı kombinasyon şeklinde etki ettirilmiş ve sonuçları tablo halinde okuyucuya sunulmuştur. 
El ile yapılan hesaplamalardaki geri dönüş süreleri Ansys programı kullanılarak kısaltılmıştır. Ve sadece ana kesitlerin incelenmesi değil bütün modelin her noktasının ayrı ayrı ele alınmasını sağlamıştır. Böylelikle gerilmelerin az olduğu bölgelerin inceltilmesi ve gerilmelerin fazla olduğu bölgelerin kalınlaştırılması veya geometrilerinde değişiklik yapılarak kuvvetlendirilmesi sağlanmıştır. Dizayn aşamasına temel teşkil etmesi için yapılan çalışmalar sonrasında iki şövelman ayağının toplam kütlesi 700 ton olarak düşünülürken, Ansys programı ile yapılan analizler sonucunda kule 497 ton olarak sonlandırılmıştır.
Yapılan statik analizden sona burkulma analizi ile kulenin 3 kritik nodu ve kritik burkulma yükü bulunmuştur. Burkulma analizi neticesinde minimum kuvvet değeri dikkate alınmış ve bu değerin elde edildiği bölgedeki eksenel gerilme değerleri ile karşılaştırılarak burkulma faktörü hesaplanmıştır. Hesaplanan burkulma faktörüne göre, kulenin burkulmadan önce saclarında akma başlayacağı görülmüş ve burkulmaya karşı emniyetli bölgede kaldığı tespit edilmiştir.
Statik analizlerin haricinde, kuleye yandan ve önden 0.45 g ivme ile deprem dalgası vurmuş gibi iki tane de deprem analizi incelenmiştir. Bütün koşullarda kulenin üzerindeki von mises gerilmeleri ve toplam deformasyonlar renkli olarak bölge bölge resimlendirilmiştir. Her analiz sonucu, sonuçlar tablosunda gösterilmiştir. Ve görülmüştür ki ihraç kulesi her yükleme durumu için güvenli bölgede kalmaktadır.

Abstract:
After investigation and long term negotiations a coal mining head frame project has prepeared for the owner of the mine HEMA ENDÜSTRİ A.Ş. Büyükdere cad. No 53 Maslak İstanbul/Türkiye.
Consideration of the procured equipment, system design, calculations, preparing the project for the production, setup, work and workers safety has prepeared according to FEM, MDG, DIN, TAS standards. Hoping that this project will assist as an example design of a head frame to whom may interest technically on coal mining process.
The principal and main information regarding the design of head tower has stated in this project. Primarily main elements of the head tower determined and then explained how to scale a head tower in light of the foregoing. Skip and cage calculations have been made mainly taking into consideration the required capacity. 
In the second part of the thesis head frame which has modelled with Solidworks program and imported to the Ansys program and has been meshed here by using three types of mesh elements. All the force flows which has to be in uniformity provided by a mesh transition. All boundary conditions are entered into program reflecting the effects of the forces that have shaped pattern six different combinations and results are presented to the reader in a table.
Return periods of  hand calculations are reduced by using Ansys software. Finally entire model has determined other than main sections determination due to advantage of Ansys. Thus, the thickness of the steel plates has reduced where the stresses seem less, in contrary the thickness of the steel plates has increased where the stresses are becoming high or by changing the geometry of design required stresses have been achieved.
Firstly the two shovelman leg mass considering the design stage as 700 tons, the head frame as a result of analysis by Ansys program was concluded as 497 tons.
Three critical modes made by the end of the tower buckling analysis after static analysis; critical buckling load has obtained. After the result of buckling analysis the minumum  force value was taken and comparing the result obtained in the region where the axial stress values obtained and calculated buckling factor. According to the calculated buckling factor, it was seen that yield starts before buckling at the steel tower and was determined to stay in the safe zone against buckling.
Apart from the static analysis, 0.45 g of acceleration as two earthquakes applied (side and front) hit the tidal wave analysis were examined. In all conditions on the head frame von mises stress and total deformation is illustrated by regions in different colors. All analysis results are shown in the table and it was found that the head frame is in safe zone for each analysis.
Head frame which is used to carry molet and top crane, positioned on the mine. It can be made steel or concrete construction. It is consisting cage and skips. 
Molets used to pilot for the wires which is covered by viscous putty and to determine the friction force to hold and pull the skip or cage. Molets contain PE 1000 material inside to guide the rope. 
Drum is used to drive the system, in both directions for efficiency when pulling the skip up let the other one go into shaft. Mostly the drums are on ground but some types designed for working on top of the head frame.
Skips are special bucket which are used for the transportation of ore or stone. In the loading station, filling the ore to skip from the top, when it comes the unloading station, by opening of the slide door; it is discharging by means of gravity.
Cages are one or more layers of steel construction cabin which works in vertical shafts to carry workers; material and lining (car). The extracted material may not be directly loaded into the cage. Ore or stones are carred inside this linings.  According to the skips, their operating speeds planned slower because of carrying workers.
Wires carrying skip or cage can be determined in three main topics. The first is have long physical life under the high friction force, the second is connects skip/skip underneath them to maintain balance, these are the high density steel wires, and the last one is in use for guiding the skip/cage and the counterweight and these need to be resistant to corrosion.
After planning the information about the mine capacity per year, how deep is vertical shaft and the location of the project, and finally the capacity are used for setting the size of the skips and cage. Skip/cage periods in a day are determined by the same way but using the daily basis. Set of position of the molets on head frame has determined by using the data herein above (capacity, sizes of skips and cage).
Tensions in the wires used for determining the leg angles of the head frame.  Tension differences in the wires  T1 and T2; T3 and    T4  can be determined with the formula "Koepe friction". After finding the leg angles it is possible to define the principal construction in the solidworks.
The friction (or Koepe) hoist is a machine where one or more ropes pass over the drum from one conveyance to another or from a conveyance to a counterweight. In either case, separate tail ropes are looped in the shaft and connected to the bottom of each conveyance or counterweight. The use of tail ropes lessens the out-of-balance load and hence the peak horsepower required of the hoist drive. When compared with a drum hoist for the same service, the tail ropes reduce the required motor HP rating by about 30%, but the power consumption remain virtually the same. Tail ropes have been used for a few double drum hoist installations to the same effect, but this practice has not gained acceptance by the mining industry.  
The difference between the lines determined by the formula.
Tload = Thold eμα
When we check skip calculations; depending on calculated results of the how much load the skips will carry, the safety factor, engine power will be determined afterwards by making the controls of the chosen wire and the engine. All work period shown on the speed/time chart.  When the skip is on the top  being unloaded, the one in the bottom is being loaded. A single time of the period is; unload time + acceleration time + constant speed time + deceleration time. By using this period, how much ore will be taken from this shaft can be calculated.
Cage operation is different from the operation of skip. Skips, while working as skip-skip; cage works against counterweight. Cage take ore at loading station at bottom of the shaft and unload at unloading station at top level and cage turns back to the loading station at bottom of shaft. And after this cage period is finishing. Therefore cage period has calculated according to; loading time + acceleration time + constant speed time + deceleration time + unloading time + acceleration time + constant speed time + deceleration time. The total of these make one period. By using this period, how much ore or how many workers transported from this shaft can be calculated.
When calculation of the head frame section area, we apply all forces on head frame (etc. wind, gravity…) and we calculate the force on the single leg and then we arrange the steel plates thickness and sizes. When sizing the leg of head frames section it is better to design rectangular shape rather than square shape. The strength of the head frame shall increase due to selection of top and bottom steel plates more thicker than the side steel plates. For more information pls refer "Theoritical section area" in thesis.
Note that if wind force impact on the head frame; yield stress of the material should be accepted 65%, if there is no wind force impact on head frame yield stress of the material should be accepted  60%. For example if we select S235J0 steel plate and we apply wind impact on head frame, we must use 153N/mm2 for calculations. But S275J0 steel plates are oftenly used at head towers . And important sections on the head frame as under molet beams or  shovelman legs should be better to choose S355J0 steel plates. 
This project can be used in every kind of mining for designing the head frame.