DAİRESEL AGREGALI MODEL BOŞLUKLU BETONLARIN DİNAMİK DAVRANIŞININ SONLU ELEMAN YÖNTEMİ İLE ANALİZİ

Yıl 2017, Cilt: 22 Sayı: 3, 277 - 290, 01.12.2017

Ayda Şafak Ağar Özbek , Jaap Weerheıjm Klaas Van Breugel

https://doi.org/10.17482/uumfd.350493

Öz

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 direct entegrasyon metodu kullanılarak dairesel agregalı boşluklu betonlar incelenmiştir. Boşluklu betonlar ve bir yalın betonda basınç gerilmesi kontürlerinin gelişiminden yola çıkarak dalga ilerlemesi hızı tahmin edilmiştir. Hesaplanan değerlerin literatürdeki değerlere ve deneysel ultrases dalga 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 konsantrasyonları 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.

Anahtar Kelimeler

Boşluklu beton, Açık sonlu eleman analizi, Dinamik analiz

Finite Element Analysis of the Dynamic Behavior of Model Porous Concretes with Circular Aggregates

Öz

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.

Anahtar Kelimeler

Porous concrete, Explicit finite element analysis, Dynamic analysis, Drop weight impact test

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