Boşluklu Betonun Darbe Yükü Altındaki Davranışının Mezoskopik Analizi

Yıl 2017, Cilt: 28 Sayı: 2, 7823 - 7844, 01.04.2017

Ayda Şafak Ağar Özbek Ronnie Refstrup Pedersen Jaap Weerheıjm

https://doi.org/10.18400/tekderg.304067

Öz

Boşluklu beton, yüksek
miktarda mezo-boyutta hava boşluğu içeren özel bir tip betondur. İçerdiği
boşluklar nedeniyle boşluklu betonun mekanik özellikleri normal betonlardan
oldukça farklıdır. Bu nümerik çalışmanın amacı, boşluklu betonun dinamik yük
altındaki davranışının mezoskopik olarak analiz edilmesidir. Gerçekleştirilen
sonlu eleman analizlerinde, açık direkt entegrasyon (explicit direct
integration) yöntemi kullanılmıştır. Betonun çimento bazlı fazlarının
tanımlanmasında Beton Hasar Plastisite Modeli kullanılmıştır. Boşluklu betonun
dört fazlı bir malzeme olarak gerçeğe yakın bir şekilde temsil edilebilmesi
için her bir fazın ayrı bir şekilde tanımlanabildiği bir sonlu eleman ağı
geliştirme programı oluşturulmuştur. Boşlukların etkilerinin daha iyi araştırılabilmesi
için dairesel boşluklar içeren yalın betonlar şeklinde tanımlanmış model
boşluklu betonlar ayrıca incelenmiştir. Gerçek boşluklu betonların nümerik
incelemeleri ile elde edilen sonuçlar, gerek darbe dayanımı gerekse çatlak
dağılımı yönünden deneysel sonuçlarla uyum göstermektedir.

Anahtar Kelimeler

Açık zaman hesabı, mezoskopik analiz, boşluklu beton, beton hasar plastisite modeli

Mesoscopic Analysis of the Behavior of Porous Concrete under Impact Loading

Öz

Porous concrete is a special type of cementitious material incorporating
a high amount of meso-sized air pores that
makes its mechanical characteristics markedly different from normal concrete.
The objective of this numerical study is
mesoscopically analyzing the behavior of porous concrete under dynamic loading.
In the finite element analyses, explicit direct integration method was adopted.
Concrete Damage Plasticity Model was selected to define the material properties
of the cementitious phases. With the aim of realistically representing porous
concrete as a four-phase material, a mesh generation program was developed
where each phase was separately defined. In order to better investigate the
effects of the properties of pores, model porous concretes were also analyzed
in the form of plain concrete meshes incorporating circular pores. The
numerical analysis results of real concrete mixtures were in good agreement
with the experimental results both in terms of quantifying the impact strength
as well as demonstrating a realistic crack pattern formation for the porous
concretes that have been analyzed. 

Anahtar Kelimeler

Explicit time integration, mesoscopical analysis, porous concrete, concrete damaged plasticity

Kaynakça

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