Hakan GÖKDAĞ, Yılmaz ARISOY, OSMAN KOPMAZ

CEVAP YÜZEYİ YAKLAŞIMI İLE TAŞIT KOLTUĞU SONLU ELEMAN MODELİNİN GÜNCELLENMESİ

Ana sanayi firmaları üretimini talep ettikleri taşıt koltuklarının belirli şartnamelere uygun olmasını isterler. İmalatçı firma bu durumda koltuğun prototipini üretip birtakım değiştirme ve iyileştirmelerle teknik şartları sağlamaya çalışabilir. Fakat bu yol pahalı ve zaman alıcıdır. Bu durumda alternatif yöntem koltuğun sonlu eleman modelini geliştirmek ve üzerinde parametrik çalıştırmalar gerçekleştirmektir. Bu çalışmada öncelikle bir ticari araç koltuğunun iskelet aksamına eklenen sünger, kılıf, sırt tahtası gibi katmanların koltuğun ileri-geri ve yanal doğrultudaki modal parametrelere etkisi deneysel olarak incelenmiştir. Buradan elde edilen sonuçlara göre koltuk iskeleti sonlu eleman modeline katmanlar çeşitli kütle ve katılık parametreleriyle eklenmiştir. Daha sonra sonlu eleman modelinin gerçek koltuk modeliyle uyumlu olması için bu parametrelerin uygun değerleri cevap yüzeyi yaklaşımı ile belirlenmiştir. Ayrıca bu yöntemle, ilgili katmanların hangilerinin daha etkili olduğu da görülmüştür. Sonuç olarak, sonlu eleman modeli ile elde edilen temel frekansların her iki doğrultu için deneysel frekanslarla uyumlu olduğu, özellikle ileri-geri harekette frekans cevabı fonksiyonu genliklerinin de birbirine oldukça yakın olduğu görülmüştür.

Anahtar Kelimeler:

Taşıt koltuğu, Sonlu Eleman, Titreşim, Cevap yüzeyi, Model Güncelleme

Model Updating of a Vehicle Seat Finite Element Model by the Response Surface Method

Vehicle manufacturers demand vehicle seats to be in accordance with certain specifications. Therefore, a seat manufacturer company may produce a prototype of the seat so that the specifications may be satisfied by various modifications and improvements. However, this is expensive and time consuming approach. As an alternative, finite element model of the seat may be developed so that some parametric studies may be performed before manufacturing. In this work, first, experimental studies are implemented to study the influence of layers added to the metal structure such as foam, seat cover, backrest board to seat’s foreaft and lateral modal properties. Outcomes of these studies are considered to define layers as additional mass and stiffness components in the software environment. Later, response surface methodology is utilized to determine suitable values of the layer components so as to match the finite element model with the real one. Besides, which layer parameters are dominant in the model is figured out by this method. Finally, it is concluded the finite element model updating is achieved by the response surface method, since the experimental and the computational frequencies for both foreaft and lateral frequencies are in good agreement, and especially the foreaft frequency response function amplitudes of the finite element and real model are compatible.

Keywords:

Vehicle seat, Finite element, Vibration, Response surface, Model updating,

PDF

___

Marwala, T (2010) Finite-Element Model Updating Using Computational Intelligence Techniques: Application to Structural Dynamics, Springer-Verlag, London. doi: 10.1007/978-1-84996-323-7.
Wang, Q. ve Deng, X. (1999). Damage detection with spatial wavelets. International Journal of Solids and Structures, 36, 3443-3468. doi: 10.1016/S0020-7683(98)00152-8.
Sehgal, S. ve Kumar, H. (2014) Structural dynamic finite element model updating using Derringers Function: A Novel Technique. Wseas Transactions On Applied And Theoretical Mechanics, 9, 11-26. (http://www.wseas.org/multimedia/journals/mechanics/2014/a045711-133.pdf).
Ren, W.X. ve Chen, H.B. (2010). Finite element model updating in structural dynamics by using the response surface method. Engineering Structures, 32, 2455-2465. doi: 10.1016/j.engstruct.2010.04.019
Shan, D, Li, Q., Khan, I. ve Zhou, X. (2015) A novel finite element model updating method based on substructure and response surface model. Engineering Structures, 103, 147 doi: 10.1016/j.engstruct.2015.09.006
Jninkwan, A, ve Singh, J. (2014). Simulation of moment deflection test on driver seat of car using finite element analysis. International Journal of Science and Research, 3(7), 299-303. https://www.ijsr.net/archive/v3i7/MDIwMTQ5OTI=.pdf
Grujicic, M, Pandurangan, B., Arakere, G. Bell, W.C., He, T. ve Xie, X. (2009). Seat-cushion and soft-tissue material modeling and a finite element investigation of the seating comfort passenger-vehicle occupants. Materials Design, 30, 4273-4285. https://doi.org/10.1016/j.matdes.2009.04.028.
Liu, C., Qiu, Y., Griffin, M.J. (2013). Finite element modelling of human-seat interactions: vertical in-line and fore-and-aft cross-axis apparent mass when sitting on a rigid seat without brackets and exposed to vertical vibration. Ergonomics, 58(7), 1207-1219. doi: 10.1080/00140139.2015.1005164
Zhang, X., Qiu, Y., Griffin, M. (2014). Developing a simplified finite element model of a car seat with occupant for predicting vibration transmissibility in the vertical direction. Ergonomics, 58(7), 1220-1231. doi: 10.1080/00140139.2015.1005165
Myers, R.H., Montgomery, D.C. ve Andersen-Cook, C.M. (2009). Response Surface Methodology: Process and Product Optimization Using Designed Experiments, John Wiley & Sons, New Jersey.
Fang, S-E. ve Perera, R. (2011). Damage identification by response surface based model updating using D-optimal design. Mechanical Systems and Signal Processing, 25, 717-733. doi:10.1016/j.ymssp.2010.07.007.
Mukhopadhyay, T., Dey, T.K., Chowdhury, R.. ve Chakrabarti, A. (2015). Structural damage identification using response surface-based multi-objective optimization: A comparative study, Arab J Sci Eng, 40,1027-1044. doi: 10.1007/s13369-015-1591-3.
Banerjee, A., Panigrahi, B. ve Pohit, G. .(2015). Crack modelling and detection in Timoshenko FGM beam under transverse vibration using frequency contour and response surface model with GA, Nondestructive Testing and Evaluation, doi: 10.1080/10589759.2015.1071812.
He, J. ve Fu, Z. (2001). Modal Analysis, Woburn, MA: Butterworth-Heinemann.
Efe, H ve Çağatay, K. (2011). Çeşitli masif ağaç malzemelerin bazı fiziksel ve mekanik özelliklerinin belirlenmesi, Politeknik Dergisi, 14, 55-61. doi: 10.2339/2007.10.3.303-311.
http://kisi.deu.edu.tr/burak.felekoglu/17.ahsap.pdf, Erişim Tarihi: 23.10.2018, Konu: Ahşap malzemelerin teknik özellikleri
Parsopoulos, K. E. ve Vrahatis, M. N. (2010). Particle Swarm Optimization and Intelligence: Advances and Applications, IGI Global, Hershey, PA, USA.