Malzeme Özelliklerinin Titreşim Testi Verilerine Dayalı Model Kalibrasyon Yöntemiyle Belirlenmesi

Abstract

Günümüzde yapılarda çok farklı türde yapı malzemeleri kullanılabilmektedir. Malzemelerin mekanik özellikleri değişkenlik göstermektedir. Bu nedenle malzeme özelliklerinin doğru olarak belirlenmesi oldukça önemlidir. Malzeme özelliklerinin tanımlanmasında kullanılan başlıca parametre elastisite modülüdür. Bu çalışmada, yapı elemanlarının elastisite modülü çevresel titreşim testi verilerinden elde edilen dinamik karakteristikler kullanılarak model kalibrasyon yöntemiyle belirlenmiştir. Önerilen yöntemin uygulaması bir çelik yapı elemanı üzerinde sunulmuştur. İlk olarak seçilen çelik yapı elemanı üzerinde çevresel titreşim testi yapılarak deneysel olarak doğal frekanslar elde edilmiştir. Deneysel ölçümler için ivmeölçerlerden ve sinyal toplama ünitesi olarak kullanılan elektronik devreden oluşan bir ölçüm sistemi tasarlanmıştır. Bu ölçüm sistemiyle alınan veriler bilgisayar ortamına aktarılmış ve Matlab programında analiz edilmiştir. SAP2000 paket programı kullanılarak sonlu eleman yöntemiyle de teorik doğal frekanslar bulunmuştur. Deneysel ve teorik sonuçlar arasındaki fark, Matlab programında oluşturulan yazılım aracılığıyla SAP2000 programında oluşturulan sonlu eleman modelinde elastisite modülü değiştirilerek yapılan tekrarlı analizler sonucunda en aza indirilmiştir. Bu işlemler sonucunda çelik elemanın kalibre edilmiş sonlu eleman modeli ve elastisite modülü elde edilmiştir.

Keywords

• Elastisite modülü,Doğal frekanslar,Malzeme özelliği,Modal analiz,Model kalibrasyon,Titreşim testi

Identification Material Properties By Modal Calibration Method Based On Ambient Vibration Tests

Abstract

Nowadays, different structural members can be used in structures. The mechanical properties of the materials are variable. For this reason, it is very important to identify the material properties correctly. The main parameter used to define the material properties is the elasticity modulus. In this study, the elasticity modulus of structural members was determined by Model Calibration Method using dynamic characteristics obtained from Ambient Vibration Test data. The application of the proposed method was presented on a steel structure member. First of all, experimental natural frequencies were obtained by conducting Environmental Vibration Test on the selected model. A measurement system consisting of accelerometers for experimental measurements and an electronic circuit used as signal collection unit are designed. The data obtained from this measurement system were transferred to the computer environment and analyzed in the Matlab program. Using the SAP2000 package program, the theoretical natural frequencies were found by Finite Element Method. The difference between the experimental and theoretical results was reduced to the lowest as a result of repeated analysis by modifying the elasticity modulus in the Finite Element model created in SAP2000 program via software generated in Matlab. The calibrated finite element model and the elasticity modulus of the steel structural member are determined by the process.

Keywords

• Elasticity modulus,Natural frequencies,Material property,Modal analysis,Modal calibration,Vibration test

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