Hidrolik giyotin makas için dinamik zorlanma durumunun sonlu elemanlar yöntemi ile analizi
Analysis of dynamic forcing for hydraulic guillotine shear with finite element method
Yazar: MUSTAFA KAĞAN ATILGAN
Danışman: DOÇ. DR. ATAKAN ALTINKAYNAK
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Konstrüksiyon Bilim Dalı
Derece: Yüksek Lisans, 2022
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: Giyotin kesmesi = Quillotine cutting ; Sac kesme = Sheet cutting ; Sayısal hesaplama = Numerical calculation ; Sonlu elemanlar yöntemi = Finite element method

Özet:
Yapılan tez çalışmasında Pres Besleme Sistemlerinde önemli bir yeri olan Hidrolik Tahrikli Giyotin Makas için literatür araştırması yapıldı. Sistemde dinamik olarak çalışan ve kritik öneme sahip üst, orta, alt bloklar, piston mafsalı, kolonlar için sonlu elemanlar metodu kullanılarak yorulma ve ömür analizleri yapıldı. Yapılan analizler için standart ve CAD verileri mevcut bir giyotin makas modeli kullanıldı. "COİLTECH" firmasına ait GYS2B 1300 olarak adlandırılan giyotin için makine ismi kesilebilen maksimum sac genişliğine göre verilmiştir. 
Giyotin makas genel olarak pres besleme sistemlerinin vazgeçilmez bir parçasıdır. Tezde giyotin makasın sistem içerindeki konumu ve çalışması hakkında da bilgilendirmeler yer almaktadır. 
Giyotin makas içerisinde bulunan makine elemanları ve işlevleri ayrıntılı bir şekilde açıklandı. Giyotin sisteminin çalışma prensibi üzerinde duruldu. Sistemde bulunan hidrolik tahrik ünitesine bağlı olarak hidrolik kuvvet hesaplamaları yapıldı. Sistemde bulunan kesme bıçaklarına, montaj açısına ve kesilen malzemeye bağlı olarak oluşan kesme kuvvetleri hesaplandı. Bıçaklar üzerine gelen bıçak kuvvetlerine ve bunlara bağlı olarak sistemin geri kalan elemanlarının tepkileri incelendi. Sonsuz ömürle çalışması beklenen makinede bağlantı cıvatalarının dayanımları yorulmaya bağlı olarak sayısal hesplamalar ile incelendi. Giyotin makaslar sistem içerisinde milyonlarca çevrim ile çalışması beklenen sonsuz ömür prensibine göre tasarlanan makinelerdir. Bu sebeple hareketli makine elemanları için çevrimsel kuvvetler karşısında verilen tepkiler ANSYS sonlu elemanlar analizleri ile incelendi ve sonsuz ömür için gerekli yüklemeler belirlendi. Yükleme değerlerine ve sonuçlara bağlı olarak analizi yapılan makine elemanları üzerinde bir topoloji çalışması yapıldı. Yapılan çalışma sonucunda elde edilen avantajlar ve dezavantajlar değerlendirildi. Sonlu elemanlar yaklaşımı yapılırken kritik ve en çok zorlanmaya maruz kalan makine elemanları göz önünde bulunduruldu. Bu elemanlar Alt, üst, hareketli gövde ve piston mafsalları ve kolonlar olarak belirlendi. ANSYS sonlu elemanlar yöntemi ile elde edilen değerler ve sonuçlar doğrultusunda gövdeler için ağırlıkları ve maliyetleri azaltmak adına iyileştirme çalışması yapıldı. Oluşturulan yeni tasarım gövdeler için aynı şekilde sonlu elemanlar analizleri ve yüklemeler altında uygunluk değerlendirmeleri yapıldı.   
Analiz ve hesaplamaların dışında giyotin makaslarla ilgili olarak literatür araştırması kapsamında sektördeki yerine ve önemine de değinildi.

Abstract:
In the thesis study, a literature search was conducted for the Hydraulic Driven Guillotine Shear, which has an important place in Press Feeding Systems. Fatigue and life analyze were performed using the finite element method for the upper, middle, lower blocks, piston joints, and columns that operate dynamically and have critical importance in the system. A guillotine shear model with standard and CAD data was used for the analysis. The machine name for the guillotine named GYS2B 1300 belonging to "COILTECH" company is given according to the maximum sheet width that can be cut.
Guillotine shears are an indispensable part of press feeding systems in general. Sheet metal cutting is performed without removing chips. The processing of the metal sheet, which is difficult to cut, by breaking it off is called guillotine shear cutting. The cutting process in guillotine shears has the same principle as the shears we use in daily life. Guillotine shears have double blades. These knives are divided into two as fixed and movable. While the lower blade is stationary; the upper blade is in motion. There is a gap between the upper and lower blades that cut. This gap changes according to the thickness feature of the sheet to be cut. For this reason, it is also called double-sided. Previously done manually; Nowadays, with the development of technology, it is computer controlled. The guillotine shear is actually a workbench. Guillotine shear cutting is performed by entering the metal data into the system. The thickness of the sheet and how it will be cut is defined on the computer and the process is performed. The cutting capacity of guillotine shears therefore varies a lot. Depending on the change shown; Production dimensions also change. This way of producing within the system ensures standardization. Like this, serial cutting is performed without errors. The thesis also includes information about the position and operation of the guillotine shears in the system. It is used in press feeding and cut-to-length lines. Cut-to-length lines are known as machine lines that make it possible to cut coiled sheets at the desired level and size. Coils can be cut very smoothly in line with these machines, which makes it possible for cut-to-length lines to occupy a special position in the industrial sector. Press feeding line; It is the whole system that will feed the press that brings the flat sheet to the desired form, formed by the uncoilers and drivers. Sheet material is available in roll form at the manufacturer. Before being fed into the press, it must be flattened and cut into pieces. Separation is usually carried out with the help of guillotine shears for flat sheets. In the developing industry, such systems work in integration with the press. Since the system works as a whole, the working speeds vary in proportion to the press speed. Such systems are widely used in large industries. Industries with continuous and high production rates and volumes such as automotive and white goods have to keep up with this speed in such systems. It is much more important that the machine made is fast and suitable for mass production, as well as producing a smooth product. Therefore, the applied forces and stresses must be at a level that will produce the final product in a near-perfect manner. Since the forces applied in such machines are hydraulically driven, the time is inversely proportional to the increase in force. Therefore, an optimization is aimed at this point. Generally, this approach is based on aiming for maximum production in a short time with minimum force that will produce the end product in an acceptable way.
The machine elements and functions in the guillotine shears are explained in detail. The working principle of the guillotine system was emphasized. Hydraulic force calculations were made depending on the hydraulic drive unit in the system. The cutting forces were calculated depending on the cutting blades in the system, the mounting angle and the material being cut. The reactions of the remaining elements of the system, depending on the blade forces on the blades, were examined. All connections on the machine are bolt connections and it is of great importance that these connections are made at appropriate torque values. This is especially important during the assembly process of the blades. The importance of this situation can be understood more clearly when it is considered that the spacing between the blades should cut smoothly and without bending the sheet metal. Bolt conformity assessment was made analytically for the critically important bolt connections in the system. The strengths of the connecting bolts in the machine, which is expected to work with an indefinite life, were examined with numerical calculations depending on fatigue. Guillotine shears are machines designed according to the principle of infinite life, which is expected to work with millions of cycles in the system. For this reason, the responses of moving machine elements to cyclical forces were examined with ANSYS finite element analysis and the necessary loadings for eternal life were determined.
ANSYS is an analysis program that is used for product or system analysis in many engineering applications and contains many modules in itself. It uses several computer-based numerical methods to solve physical problems. ANSYS provides solutions to the necessary problems by analyzing many areas such as fluid flow, heat transfer, stress analysis and material strength.
It is aimed to make a transition to finite element analysis by mathematically calculating the hydraulic forces acting on the elements on the machine and using these forces directly on the system. Fatigue effects of the cyclical stresses on the machine and, accordingly, determining the life of the machine or determining the necessary conditions for the machine to work in eternal life conditions constitute the main objective of the study. As mentioned, fast cycles and cyclic loads related to these cycles occur in such machines. A topology study was performed on the machine elements analyzed based on the loading values and results. The advantages and disadvantages obtained as a result of the study were evaluated. While making the finite element approach, the critical and most stressed machine elements were taken into consideration. These elements were determined as lower, upper, movable body and piston joints and columns. In line with the values and results obtained by the ANSYS finite element method, an improvement study was carried out for the bodies in order to reduce the weights and costs. Finite element analyzes and conformity assessments under loadings were made for the newly created bodies in the same way.
Getting to know the guillotine sheet shearing machine more closely and understanding its place and importance in the industry with the researches done in the thesis, Explaining the mechanical elements of the guillotine sheet shearing machine in detail with the materials and manufacturing methods, Depending on the working principle of the guillotine sheet shearing machine, Examining the response of the remaining machine elements to these cyclical stresses or possible damage, Examining the advantages and disadvantages of hydraulic driven systems, Examining the fatigue strength of the machine and its continuity with the finite element analyzes to be made on the critical parts of the guillotine shearing machine used as a standard for sheet metal cutting. It is aimed to have an idea, at the same time and to gain an advantage over the part with topology analysis.
In the literature study, the cutting process types and the place of hydraulic guillotine shears among these types were examined. Hydraulic guillotine shears work with hydraulic drive. Pistons in the system perform the upper blade movement. The lower blade is fixed. The upper blade is positioned at an angle. Cutting is performed on the material in between with the upper blade movement. The advantages and disadvantages of hydraulic guillotine shears compared to other cutting machines were evaluated.