Dairesel agregalı model boşluklu betonların dinamik davranışının sonlu eleman yöntemi ile analizi
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Date
2017-12-31
Authors
Özbek, Ayda Şafak Ağar
Weerheijm, Jaap
Breugel, Klaas van
Journal Title
Journal ISSN
Volume Title
Publisher
Uludağ Üniversitesi
Abstract
Boşluklu beton, agrega tanelerinin birbirine ince bir çimento hamuru tabakası ile bağlanması sonucu oluşan, yüksek oranda mezo-boyutta boşluk içeren özel bir tip betondur. Güvenlik uygulamalarında kullanılmak üzere dayanımı arttırılmış boşluklu betonlar geliştirilmesi amacıyla gerçekleştirilen bir projede, boşluklu betonların dinamik davranışları sonlu eleman yöntemiyle analiz edilmiştir. Analizlerde, ABAQUS/Explicit programında tanımlı bulunan açık doğrudan entegrasyon metodu kullanılarak dairesel agregalı boşluklu betonlar incelenmiştir. Boşluklu betonlar ve bir yalın betonda eş basınç eğrilerinin gelişiminden yola çıkarak dalga ilerlemesi hızı tahmin edilmiştir. Hesaplanan değerlerin literatürdeki değerlere ve deneysel ultrases dalgası hızı sonuçlarına çok yakın olduğu belirlenmiştir. Bunun yanında iki farklı boyutta agrega içeren boşluklu betonun dayanımlarının birbirine neredeyse eşit olduğu tespit edilmiştir. Boşluklu betonlarda oluşan hasar dağılımı ve gerilme yığılmaları incelendiğinde, deneylerde de tespit edildiği gibi dinamik yükleme altında çoklu çatlaklar ve yaklaşık olarak agrega boyutunda fragmanlar oluştuğu görülmektedir. Bu nedenle, fragman boyutunun agrega boyutu tarafından belirlendiği tespit edilmiştir.
Porous concrete is a special type of concrete that includes a high amount of meso-size air pores and is formed by the aggregate particles assembled by a thin layer of cement paste. In the scope of a research project, having an objective of designing enhanced strength porous concretes to be used in safety applications, dynamic properties of porous concretes were analyzed with finite element method. In the analyses, porous concretes with circular aggregates were analyzed by using the explicit direct integration technique implemented in ABAQUS/Explicit. Based on the analysis results, stress wave propagation speeds of porous concretes and a plain concrete were estimated based on stress contours. The numerically estimated values were found to be very close to the reference values in literature and the experimental results. On the other hand, the impact strengths obtained for two model porous concretes having different aggregate sizes were found to be nearly equal. When the computed damage distributions and stress concentrations were examined, it was seen that under dynamic loading, the fragments formed were approximately at the size of aggregates. Therefore, it is concluded that the fragment size in porous concretes is mainly determined by the size of the aggregates incorporated in the mixture.
Porous concrete is a special type of concrete that includes a high amount of meso-size air pores and is formed by the aggregate particles assembled by a thin layer of cement paste. In the scope of a research project, having an objective of designing enhanced strength porous concretes to be used in safety applications, dynamic properties of porous concretes were analyzed with finite element method. In the analyses, porous concretes with circular aggregates were analyzed by using the explicit direct integration technique implemented in ABAQUS/Explicit. Based on the analysis results, stress wave propagation speeds of porous concretes and a plain concrete were estimated based on stress contours. The numerically estimated values were found to be very close to the reference values in literature and the experimental results. On the other hand, the impact strengths obtained for two model porous concretes having different aggregate sizes were found to be nearly equal. When the computed damage distributions and stress concentrations were examined, it was seen that under dynamic loading, the fragments formed were approximately at the size of aggregates. Therefore, it is concluded that the fragment size in porous concretes is mainly determined by the size of the aggregates incorporated in the mixture.
Description
Keywords
Boşluklu beton, Açık sonlu eleman analizi, Dinamik analiz, Serbest düşme deneyi, Porous concrete, Explicit finite element analysis, Dynamic analysis, Drop weight impact test
Citation
Özbek, A. Ş. A. vd. (2017). "Dairesel agregalı model boşluklu betonların dinamik davranışının sonlu eleman yöntemi ile analizi". Uludağ Üniversitesi Mühendislik Fakültesi Dergisi, 22(3), 277-290.