Otomotiv ön aydınlatma gövde elemanında termal etkilerin rezonans frekansındaki değişimlere etkisinin deneysel olarak incelenmesi
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Date
2019-09-27
Authors
Sönmezay, Birhat
Journal Title
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Publisher
Bursa Uludağ Üniversitesi
Abstract
Otomotiv ön aydınlatma sistemleri günümüzde hem tasarım hem de güvenlik açısından önemli elemanlardır. Bu sistemlerin esas amacı gece sürüşü esnasında yolu aydınlatma ve çevredeki araç veya yayalara aracın varlığını, hızını, büyüklüğü yada sürüş yönünü belli etmektir. Günümüzde çok karmaşıklaşan bu sistemlerin daha tasarım aşamasında iken test esnasında meydana gelebilecek hataların belirlenmesi maliyet açısından büyük önem arz etmektedir. Bu çalışmada otomotiv endüstrisinde kullanılan malzemelerden biri olan polipropilen (PP)’in içine hacimsel olarak % 40 talk katılması ile oluşturulmuş PP TD40 malzemesinden yapılmış bir aydınlatma gövdesi elektrodinamik sarsıcıya bağlanmış ve 1-300 Hz aralığında sinüs tarama testi yapılmıştır. Bu test ardından toplanan ivme genliği ve frekans verileri ile yarım güç noktası, modal sabit ve sönüm oranı gibi analiz parametreleri hesaplanmıştır. Bu parametrelerle koşturulan Ansys® sonlu elemanlar analiz paket programı sonuçlarından elde edilen ivme genliği ve frekans grafikleri ve test sonucundaki ivme genliği ve frekans grafikleri karşılaştırılmıştır. Sonuçlar arası fark en fazla %11,3 ve en az %0,26 olmuştur. Fikstür tabanına yerleştirilen ivme ölçerden toplanan zamana bağlı ivme verileri sonlu elemanlar analiz programına zamana bağlı ivme kuvveti olarak girilmiş ve 3 boyutlu model üzerinden belirlenen noktadaki birim uzama verileri, gövdede aynı noktaya yerleştirilen birim uzama ölçer verileri nCode® programı yardımıyla karşılaştırılmıştır. Birim uzama ölçümünde %12,4 fark ile sonuçlar elde edilmiştir. Veri toplama sisteminden alınan frekans-ivme verileri ise pencereleme tipi, üst üste bindirme aralığı ve çözünürlük gibi fourier dönüşümü (FD) parametreleri kullanılarak yeniden hesaplanmış ve hesaplanan veriler sarsıcı test düzeneği verileriyle karşılaştırılmıştır.
Automotive front lighting systems are important elements both in terms of design and safety. The main purpose of these systems is to illuminate the road during night driving and to determine the presence, speed, size or direction of the vehicle to the surrounding vehicle or pedestrians. Nowadays, it is very important to determine the errors that may occur during the test phase of these systems, which are very complicated. In this study, a lighting housing made of PP TD40 material, which is formed by adding 40% by volume of talc into polypropylene (PP) which is one of the materials used in automotive industry, is connected to the electrodynamic shaker and sinus scanning test is performed in the range of 1-300 Hz. After this test, acceleration amplitude and frequency data were collected and analysis parameters such as half power points, modal constant and damping ratio were calculated. The acceleration amplitude and frequency graphs obtained from the results of the Ansys® finite element analysis program run with these parameters and the acceleration amplitude and frequency graphs of the test results were compared. The difference between the results was at most 11.3% and at least 0.26%. The time dependent acceleration data collected from the accelerometer placed on the fixture base were entered into the finite element analysis program as time dependent acceleration force and the strain data at the point determined on the 3D model were compared with the help of the nCode® program placed on the same point on the housing. The results were obtained with 12.4% difference in strain measurement. The data acquisition system’s data was recalculated using various fourier transform (FT) parameters such as windowing function, overlapping, resolution and the calculated data were compared with the shaker test setup data.
Automotive front lighting systems are important elements both in terms of design and safety. The main purpose of these systems is to illuminate the road during night driving and to determine the presence, speed, size or direction of the vehicle to the surrounding vehicle or pedestrians. Nowadays, it is very important to determine the errors that may occur during the test phase of these systems, which are very complicated. In this study, a lighting housing made of PP TD40 material, which is formed by adding 40% by volume of talc into polypropylene (PP) which is one of the materials used in automotive industry, is connected to the electrodynamic shaker and sinus scanning test is performed in the range of 1-300 Hz. After this test, acceleration amplitude and frequency data were collected and analysis parameters such as half power points, modal constant and damping ratio were calculated. The acceleration amplitude and frequency graphs obtained from the results of the Ansys® finite element analysis program run with these parameters and the acceleration amplitude and frequency graphs of the test results were compared. The difference between the results was at most 11.3% and at least 0.26%. The time dependent acceleration data collected from the accelerometer placed on the fixture base were entered into the finite element analysis program as time dependent acceleration force and the strain data at the point determined on the 3D model were compared with the help of the nCode® program placed on the same point on the housing. The results were obtained with 12.4% difference in strain measurement. The data acquisition system’s data was recalculated using various fourier transform (FT) parameters such as windowing function, overlapping, resolution and the calculated data were compared with the shaker test setup data.
Description
Keywords
Otomotiv aydınlatma, Modal analiz, Yarım güç metodu, Sonlu Elemanlar Modeli, Fourier Dönüşümü, Rayleigh Oransal Sönüm, Polipropilen, Automotive lighting, Modal analysis, Half-power method, Finite Element Model, Fourier Transform, Rayleigh Proportional Damping, Polypropylene
Citation
Sönmezay, B. (2019). Otomotiv ön aydınlatma gövde elemanında termal etkilerin rezonans frekansındaki değişimlere etkisinin deneysel olarak incelenmesi. Yayınlanmamış yüksek lisans tezi. Bursa Uludağ Üniversitesi Fen Bilimleri Enstitüsü.