Bir dizel motorun burulma titreşim analizi ve optimizasyonu
Yükleniyor...
Tarih
2022
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Necmettin Erbakan Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, içten yanmalı motorlarda burulma sönümleme elemanı olarak kullanılan burulma
titreşim kasnağının, dayanım ve motor dinamiğine etki eden geometrik ve malzemeye dayalı
parametrelerinin nümerik analizler ile statik, dinamik, titreşim ve yorulma hesaplamaları yapılmış ve
bu hesaplamalara göre optimum krank mili sistemi (krank mili, volan ve burulma titreşim kasnağı)
tasarımı gerçekleştirilmiştir. Çalışmada dört zamanlı dört silindirli bir dizel motorun krank sistemi ele
alınmıştır. Bu krank sisteminde literatüre DMRV-TVD olarak kazandırılan çift kütleli, kauçuk ve
vizkos yağdan oluşan gerçek bir burulma titreşim kasnağı (ÇKKV-BTK) kullanılmıştır. Öncelikle
krank sisteminin on iki serbestlik dereceli ayrık sistem modeli oluşturulmuş ve hareket denklemleri
elde edilmiştir. Hareket denklemlerinde kullanılan her elamana ait rijitlik ve sönüm katsayıları amprik
formülasyonlar kullanılarak bulunmuştur. Hareket denklemlerine göre krank sisteminin doğal frekans
değerleri ve krank milinin açı, açısal hız, açısal ivme ve tork değişim grafikleri elde edilmiştir. Doğal
frekans değerlerini hesaplama yöntemlerinden biri olan Holzer Metoduna bir yenilik getirilerek
kullanılmıştır. Zorlama yükleri ve harmonikleri tüm sistemin kütle atalet momentlerine, silindir gaz
kuvvetlerine ve Fourier serisi açılımına göre bulunmuş ve krank milinin uç kısmında oluşan açısal
deplasman elde edilmiştir. Ayrıca burulma titreşim kasnağının modal test ve sonlu elemanlar doğal
frekans analizleri yapılmıştır. Bu analizler ile amprik olarak bulunan doğal frekans sonuçları
karşılaştırılmış, kauçuk ve viskoz rijitlik ve sönümleme katsayıları doğrulanmıştır. Daha sonra krank
milinin burulma titreşimlerini sıfıra yakınsamak için hem kauçuk hem de viskoz sönümleyici malzeme
parametreleri, belirlenen sınır koşullarına ve amaç fonksiyonuna göre genetik algoritma (GA), TLBO
ve Jaya metotları kullanılarak optimize edilmiş ve sonuçlar karşılaştırılmıştır. Genetik algoritma
tabanlı optimizasyon ile burulma titreşimleri %50.17 azaltılmıştır. Bu çalışmalardan sonra, optimize
edilen ve edilmeyen değerelere göre krank sisteminin yorulma hesaplamaları yapılmış ve
hesaplamalarda yedi farklı yöntem (Narrow- Band, Dirlik, Alpha 0.75, Ortiz Chen, Zhao Baker, Lutes
Larsen, Wirsching Light ve Benasciutti Tovo) kullanılmıştır. Sonuç olarak; Dirlik, Tovo-Benasciutti
ve Zhao-Baker metotlarından elde edilen sonuçların ortalaması alınmış ve ortalama 70km/sa. hızla
giden ve 0-5000dev/dak. aralığında çalışmış, yüksek torklu dizel bir aracın krank mili yorulma ömrü
burulma titreşim kasnağı optimize edilmeden önce 190 bin km., optimize edildikten sonra 300 bin km
olarak bulunmuştur. Çalışma sonuçlarına göre, literatürde sıklıkla incelenen hatalı krank mili tasarımı
ile meydana gelen erken yorulma hasarlarına ek olarak hatalı veya optimize edilmemiş burulma
titreşim kasnağının da krank milinde erken yorulma hasarına neden olduğunu söylemek mümkündür.
In this study, static, dynamic, vibration and fatigue calculations were made by numerical analysis of the geometric and material-based parameters affecting the strength and engine dynamics of the torsional vibration pulley, which is used as a torsional damping element in internal combustion engines, and according to these calculations, the optimum crankshaft system (crankshaft, flywheel and torsional vibration pulley) were designed. In the study, the crank system of a four-stroke four-cylinder diesel engine is discussed. In this crank system, a real torsional vibration pulley (ÇKKV-BTK) consisting of dual-mass rubber and viscous oil, which was introduced to the literature as DMRV-TVD, was used. First of all, twelve degrees of freedom discrete system model of the crank system was created and the equations of motion were obtained. The stiffness and damping coefficients of each element used in the equations of motion were found using empirical formulations. According to the motion equations, the natural frequency values of the crank system and the angle, angular velocity, angular acceleration and torque variation graphs of the crankshaft were obtained. The Holzer Method, which is one of the methods of calculating natural frequency values, is used by bringing an innovation. Forcing loads and harmonics of the whole system were found according to the mass moments of inertia, cylinder gas forces and Fourier series expansion, and the angular displacement at the tip of the crankshaft was obtained. In addition, modal testing and finite element natural frequency analyzes of the torsional vibration pulley were performed. These analyzes and empirical natural frequency results were compared and the rubber and viscous stiffness and damping coefficients were verified. Then, both rubber and viscous damping material parameters were optimized using genetic algorithm (GA), TLBO and Jaya methods according to the determined boundary conditions and objective function in order to converge the torsional vibrations of the crankshaft to zero, and the results were compared. Torsional vibrations were reduced by 50.17% with genetic algorithm-based optimization. After these studies, fatigue calculations of the crank system were made according to the optimized and nonoptimized values and seven different methods (Narrow-Band, Dirlik, Alpha 0.75, Ortiz Chen, Zhao Baker, Lutes Larsen, Wirsching Light and Benasciutti Tovo) were used in the calculations. As a result; The results obtained from the Dirlik, Tovo-Benasciutti and Zhao-Baker methods were averaged and averaged 70km/h. rapidly going and 0-5000rpm. The crankshaft fatigue life of a high-torque diesel vehicle operated in the range of 190 thousand km before the torsional vibration pulley was optimized and 300 thousand km after the optimization. According to the results of the study, it is possible to say that in addition to the premature fatigue damage caused by faulty crankshaft design, which is frequently examined in the literature, faulty or unoptimized torsional vibration pulley also causes premature fatigue damage to the crankshaft.
In this study, static, dynamic, vibration and fatigue calculations were made by numerical analysis of the geometric and material-based parameters affecting the strength and engine dynamics of the torsional vibration pulley, which is used as a torsional damping element in internal combustion engines, and according to these calculations, the optimum crankshaft system (crankshaft, flywheel and torsional vibration pulley) were designed. In the study, the crank system of a four-stroke four-cylinder diesel engine is discussed. In this crank system, a real torsional vibration pulley (ÇKKV-BTK) consisting of dual-mass rubber and viscous oil, which was introduced to the literature as DMRV-TVD, was used. First of all, twelve degrees of freedom discrete system model of the crank system was created and the equations of motion were obtained. The stiffness and damping coefficients of each element used in the equations of motion were found using empirical formulations. According to the motion equations, the natural frequency values of the crank system and the angle, angular velocity, angular acceleration and torque variation graphs of the crankshaft were obtained. The Holzer Method, which is one of the methods of calculating natural frequency values, is used by bringing an innovation. Forcing loads and harmonics of the whole system were found according to the mass moments of inertia, cylinder gas forces and Fourier series expansion, and the angular displacement at the tip of the crankshaft was obtained. In addition, modal testing and finite element natural frequency analyzes of the torsional vibration pulley were performed. These analyzes and empirical natural frequency results were compared and the rubber and viscous stiffness and damping coefficients were verified. Then, both rubber and viscous damping material parameters were optimized using genetic algorithm (GA), TLBO and Jaya methods according to the determined boundary conditions and objective function in order to converge the torsional vibrations of the crankshaft to zero, and the results were compared. Torsional vibrations were reduced by 50.17% with genetic algorithm-based optimization. After these studies, fatigue calculations of the crank system were made according to the optimized and nonoptimized values and seven different methods (Narrow-Band, Dirlik, Alpha 0.75, Ortiz Chen, Zhao Baker, Lutes Larsen, Wirsching Light and Benasciutti Tovo) were used in the calculations. As a result; The results obtained from the Dirlik, Tovo-Benasciutti and Zhao-Baker methods were averaged and averaged 70km/h. rapidly going and 0-5000rpm. The crankshaft fatigue life of a high-torque diesel vehicle operated in the range of 190 thousand km before the torsional vibration pulley was optimized and 300 thousand km after the optimization. According to the results of the study, it is possible to say that in addition to the premature fatigue damage caused by faulty crankshaft design, which is frequently examined in the literature, faulty or unoptimized torsional vibration pulley also causes premature fatigue damage to the crankshaft.
Açıklama
Doktora Tezi
Anahtar Kelimeler
Dizel Motor, Burulma Titreşimi, Sönümleme, Kasnak, Volan, Krank Sistemi, Kauçuk, Vizkoz Yağ, Modal Analiz, Sonlu Elemanlar, Optimizasyon, Yorulma Ömrü, Diesel Engine, Torsional Vibration, Damping, Pulley, Flywheel, Crank System, Rubber, Viscous Oil, Modal Analysis, Finite Elements, Optimization, Fatigue Life
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Sezgen, H. Ç. (2022). Bir dizel motorun burulma titreşim analizi ve optimizasyonu. (Yayımlanmamış doktora tezi). Necmettin Erbakan Üniversitesi, Fen Bilimleri Enstitüsü Makine Mühendisliği Anabilim Dalı, Konya.
