Disk keskilere ait kesme kuvveti tahmini için bir bulanık mantık modeli
A fuzzy logic model to estimate cutting force of the CCS disc cutter
Yazar: ALİ CAN KÖSE
Danışman: DOÇ. DR. ÖMÜR ACAROĞLU ERGÜN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Maden Mühendisliği Ana Bilim Dalı / Maden Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Maden Mühendisliği ve Madencilik = Mining Engineering and Mining

Özet:
Günümüzde maden ve inşaat sektöründe mekanize kazı yöntemleri yaygınlaşmış ve bu yöntemler ekonomik ve çevresel nedenlerden ötürü özellikle tercih edilir olmaya başlamıştır. Mekanize kazı makinelerinden tam cepheli tünel açma makineleri  (TBM) çok daha güvenilir olup belirli bir tünel uzunluğundan sonra da diğer makinelere göre daha ekonomik olmaktadırlar.  Bununla birlikte TBM'lerle verimli bir tünel kazısı için uygun  makinenin seçilmesi , tasarım parametrelerinin optimizasyonu ve performans tahminleri kritik bir öneme sahiptir. 
TBM'ler için önemli olan tasarım parametrelerininin hesaplanmasında gerekli olan parametrelerden birisi de bu makinelerde yaygın olarak kullanılan disk  keskilere etki eden kesme kuvvetidir. Disk keskilerin kesme kuvvetleri, TBM'lerin tasarım parametrelerinden biri olan toplam tork ihtiyacının belirlenmesinde ve ilerleme hızı, spesifik enerji gibi makine performans parametrelerinin tahmininde kullanılmaktadır.Disk  keskilere etki eden kuvvetleri  tahmin etmek için analitik, ampirik ve sayısal yaklaşımlar kullanarak birçok araştırma yapılmıştır. 
Son yıllarda bulanık mantık, karmaşık ve belirsizlik içeren konularda gerçeğe yakın sonuçlar vermesi sebebiyle araştırmalarda oldukça tercih edilen yöntemlerden birisi olmaya başlamıştır.  Yerbilimleri de belirsizliklerin ve karmaşıklıkların çok fazla olduğu bir alan olmasından dolayı bulanık mantık gibi yöntemler klasik yöntemlere göre daha iyi tahminlerde, hesaplamalarda bulunmaktadır.  
Bu çalışma da TBM'lerde yaygın olarak kullanılan sabit kesitli (CCS) disk keskilere etki eden  kesme kuvveti değerinin belirlenmesi için  Mamdani Bulanık Mantık yöntemi ile bir model yapılmıştır.  Kesme kuvvetini tahmin etmek için tek eksenli basınç dayanımı (UCS), endirekt (dolaylı) çekme dayanımı (BTS), disk çapı, disk ucu genişliği, keskiler arası mesafe ve kesme derinliği (penetrasyon) giriş parametresi kesme kuvveti ise çıkış parametresi olarak kulllanılmıştır. Giriş ve çıkış parametreleri üçgen şeklindeki üyelik fonksiyonları kullanarak sınıflandırılmış  ve giriş parametrelerinin sınıfları ile çıkış  parametresinin sınıfları arasındaki bağlantı bulanık mantık yöntemine göre eğer-ise kuralları ile kurulmuştur. Bu amaçla 540 adet kural yazılmıştır. Mamdani yöntemine göre yapılan modelin sonuçlarının doğrulanmasında gerçek lineer kesme deney sonuçlarına bakılmıştır. Elde edilen modelin sonuçları ile gerçek değerler oldukça yakın olup 0.90 korelasyon değeri elde edilmiştir. 
Sonuç olarak, bu çalışmada tam cepheli kazı makinelerinde kullanılan disk keskilere etki eden kesme kuvvetini tahmin eden bir model bulanık mantık yöntemi kullanılarak geliştirilmiştir. Model gerçek değerlere yakın sonuçlar vermekte olup  bulanık mantık yönteminin belirsizlik içeren konulara uygun olduğunu göstermektedir, bu modellerin bir avantajı da geliştirilmeye açık olmalarıdır.

Abstract:
Tunnel boring machines (TBMs), which are used for excavation in nearly all type of rock masses and geological conditions, have found widespread application in tunneling construction. Mechanical excavation of a tunnel by TBM offers numerous advantages over conventional drill and blast methods including secure and high advance rate excavation. Furthermore, they do not have the disadvantages of roadheaders which are not applied on unstable or hard rock conditions. 
The selection of excavation method is usually based on the length of excavation and rock condition. In some cases, TBM can be only option because of some environmental and political restrictions. TBMs are designed and sized in different configurations depending on the project and geological conditions. As their size changes from 1,5 m to 15 m diameter, they are generally classified as hard rock tunneling and soft ground tunneling machines.
Disc cutters, which are widely used on TBMs, are capable of cutting a variety of rock types with different properties. Single disc cutters with replaceable disc rings have been utilized on hard rock TBMs over the years and have proved their superiority about performance and reliability.
Cutting force which act on a disc are used for optimization and layout of a TBM cutterhead and machine design. Cutting force determines torque and power requirements of a machine to rotate the cutterhead at a certain penetration of the cutters.
The successful application of TBM technology is directly related to an accurate estimation of performance. Predicting the performance of a tunnel boring machine (TBM) plays an important role in the economic and time planning of tunneling projects. Error in performance estimation can result in project delays and cost over runs as seen in many case histories.
During rock excavation processes, many parameters including machine parameters, geological conditions and site-specific conditions affect the machine performance level. The complex relationship between these parameters makes predicting the performance of the machine very difficult.
In the past years, various empirical methods have been developed for the prediction of TBM performance using traditional statistical analysis techniques. Soft computing techniques are now being used as an alternative statistical tool.
The fuzzy logic is a matter of the fuzzy set theory particularly used to dealing with process imprecise information with a changed membership function. Fuzzy set theory was formalized by Zadeh (1965). In a classical set; an element belongs to, or does not belong to, a set. Because fuzzy sets describe vague concepts based on the premise that the elements used are not numbers but belong to words or the value of a linguistic variable, an element of a fuzzy set naturally belongs to the set with membership values from the interval [0, 1]. The shape of the membership function of fuzzy sets can be either linear (trapezoidal or triangular) or various forms of non-linear, depending on the nature of the system being studied.
Fuzzy models cope with the complexity of complex systems in a flexible and consistent way and more realistic results can be obtained in practice with these models. Then, the use of fuzzy logic can avoid the complex of deterministic formulas and mathematic modellings. Parameters can be modeled considering many possible variables affecting the system without assuming preconditions. Therefore, fuzzy logic method has widely been applied on almost all research area particularly including complexity and uncertainty. There are huge of successful applications of fuzzy logic in industries.
In this study, a fuzzy logic model was developed to predict the cutter force of a disc cutter based on experience and verified the database which consists of linear cutting test results generated at the Earth Mechanics Institute of the Colorado School of Mines.
Mamdani fuzzy inference system was chosen in this study. The Mamdani algorithm has become one of the most common and widely used algorithms for solving many real-world problems, because of its simplicity.
The model predicts the cutter force of a disc cutter using rock properties such as uniaxial compressive strength, brazilian tensile strength, disc dimensions such as disc diameter and tip width and cutting geometry such as spacing and penetration. 
The determination of membership function is vital for fuzzy logic. There are different types and shapes of membership functions. In this model, triangular and trapezoid types membership functions are used for inputs and output parameters due to their construction simplicity and the excellent results that had been achieved by employing them in the area of rock engineering.
The CCS disc cutter diameter which is input 1 was sized in cm. CCS disc cutter diameter ranges from 7 cm to 49 cm. It had three member functions; small, medium and big with respect to disc diameters.
Tip width of CCS disc cutter, input 2, ranged from 0,5 cm to 2,3 cm. It had three membership functions which are thin, medium and thick.
Cutting geometry variables, spacing (S) and penetration of discs (p) in the cutting process were considered as inputs 3 and 4. Spacing between discs ranges from 0,2 cm to 18 cm. It had two member functions which are small and high. Penetration (p) of disc cutter ranged from 0,01 cm to 4,1 cm and It had five member functions which are very low, low, medium, high and very high.
Rock properties, in the format of UCS and BTS values were considered as inputs 5 and 6 respectively. UCS values ranged from 20 MPa to 310 MPa and had three membership functions which are poor, fair and good. BTS values ranged from 1,5 MPa to 21 MPa. BTS and had two membership functions which are poor and good.
Cutter force (FC), output, had ten membership functions with different shapes. These included very very very low, very very low, very low, low, medium, high, very high, very very high, very very very high and very very very very high. It ranged form 0,5 kN to 75 kN.
The fuzzy model is the construction of the if–then rules, which are used to represent the fuzzy relationships between input and output fuzzy variables. In this study, a total of 540 rules were utilized for constructing the rule base of the fuzzy model.
The developed fuzzy model can provide an estimation of cutter force of disc cutters when proper and acceptable input data are entered into the model. 
The results indicated that the fuzzy model can be used as a reliable predictor of cutter force for TBM. The model FC results and real FC values were compared to verify the model. The determination coefficient (R2), of the proposed fuzzy model are 0,90. Evidently, the obtained indices indicate that the proposed fuzzy logic model can provide a good prediction for cutter force (FC).
It was concluded that the proposed fuzzy logic model was a suitable and practical technique that can be effectively used in the prediction of cutter force with acceptable error rates. The major advantage of fuzzy model in comparison with other models is that human judgment and intuition can be effectively used for the prediction of cutter force, which helps in field applications. It is clear that this model can be improved using more data from other tunneling projects over time.