Binek araç gündüz farının modal parametrelerinin belirlenmesi ve sonlu elemanlar modelinin güncellenmesi
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Date
2017-07-11
Authors
Ediz, Barış
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Publisher
Uludağ Üniversitesi
Abstract
Çalışmanın amacı bir binek araç gündüz farının modal parametrelerinin belirlenmesi ve sonlu elemanlar modelinin güncellenmesidir. Titreşen sistemlerde, Rayleigh oransal sönüm öngörüsü ile farklı doğal frekanslar için sönüm oranları tahmin edilebilmektedir. Bu çalışmada üretimde var olan bir gündüz farı üzerinde yapılan testlerle Rayleigh oransal sönüm katsayıları belirlenmiş ve sonlu elemanlar modelinde bu katsayılar kullanılarak doğrulama yapılmıştır. Böylece sonlu elemanlar dinamik yapısal analizlerinden gerçeğe daha yakın sonuçlar elde edilmesi hedeflenmiştir. Yapılan çalışmada rezonans tarama testleri ile belirlenen bir nokta üzerinden gündüz farının ivme frekans cevabı ölçülmüş ve bir tek serbestlik dereceli modal analiz metodu olan tepe tutma metodu ile modal parametreler belirlenmiştir. Modal parametreler belirlenirken Rayleigh oransal sönüm öngörüsüyle sönüm kütle matrisi ve katılık matrisi çarpanları (sırasıyla α ve β) hesaplanmıştır. Bu sabitler sonlu elemanlar modelinde kullanılarak harmonik ivme cevap analizi yapılmış ve test sonucu elde edilen cevap fonksiyonu ile karşılaştırılmıştır.
Main aim of this study is the determination of modal parameters of a Day Time Running Light (DRL) and update of Finite Element (FEA) model. By the assumption of Rayleigh proportional damping, damping ratio for all natural modes of the structure can be anticipated with good accuracy. In this study, by performing harmonic sweep test on a real structure, Rayleigh proportional damping matrix multipliers have been determined and by application of these constants on FEA model, a validation study has been performed. As a result, it is expected to get realistic results from the vibration durability FEA’s. In this study, on a determined point of DRL housing, during resonance search test, acceleration frequency response has been measured and by the assumption of SDOF modal analysis Peak Picking Method, modal parameters of the structure have been determined. By the assumption of Rayleigh proportional damping; damping mass matrix and stiffness matrix multipliers (α and β) have been calculated. Harmonic Response FEA has been performed by the application of these constants and the result FRF has been compared with the one measured during test.
Main aim of this study is the determination of modal parameters of a Day Time Running Light (DRL) and update of Finite Element (FEA) model. By the assumption of Rayleigh proportional damping, damping ratio for all natural modes of the structure can be anticipated with good accuracy. In this study, by performing harmonic sweep test on a real structure, Rayleigh proportional damping matrix multipliers have been determined and by application of these constants on FEA model, a validation study has been performed. As a result, it is expected to get realistic results from the vibration durability FEA’s. In this study, on a determined point of DRL housing, during resonance search test, acceleration frequency response has been measured and by the assumption of SDOF modal analysis Peak Picking Method, modal parameters of the structure have been determined. By the assumption of Rayleigh proportional damping; damping mass matrix and stiffness matrix multipliers (α and β) have been calculated. Harmonic Response FEA has been performed by the application of these constants and the result FRF has been compared with the one measured during test.
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Keywords
Otomotiv aydınlatma, Otomotiv gündüz farı, Modal analiz, Rezonans tarama, Sonlu elemanlar modeli güncelleme, Rayleigh oransal sönüm öngörüsü, Automotive lighting, Day time running light (DRL), Modal analysis, Resonance search, Finite element model update, Rayleigh proportional damping assumption
Citation
Ediz, B. ve Çetin, S. T. (2017). "Binek araç gündüz farının modal parametrelerinin belirlenmesi ve sonlu elemanlar modelinin güncellenmesi". Uludağ Üniversitesi Mühendislik Fakültesi Dergisi, 22(3), 1-10.