Browsing by Subject "Concrete damage plasticity models"

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    Impact resistance of deflection-hardening fiber reinforced concretes with different mixture parameters
    (Wiley-Blackwell, 2019) Banyhussan Q.S.; Yıldırım G.; Anıl Ö.; Erdem R.T.; Ashour A.; Şahmaran M.
    The impact behavior of deflection-hardening High Performance Fiber Reinforced Cementitious Concretes (HPFRCs) was evaluated herein. During the preparation of HPFRCs, fiber type and amount, fly ash to Portland cement ratio and aggregate to binder ratio were taken into consideration. HPFRC beams were tested for impact resistance using free-fall drop-weight test. Acceleration, displacement, and impact load versus time graphs were constructed and their relationship to the proposed mixture parameters were evaluated. The paper also aims to present and verify a nonlinear finite element analysis, employing the incremental nonlinear dynamic analysis, concrete damage plasticity model, and contact surface between the dropped hammer and test specimen available in ABAQUS. The proposed modeling provides extensive and accurate data on structural behavior, including acceleration, displacement profiles, and residual displacement results. Experimental results which are further confirmed by numerical studies show that impact resistance of HPFRC mixtures can be significantly improved by a proper mixture proportioning. In the presence of high amounts of coarse aggregates, fly ash, and increased volume of hybrid fibers, impact resistance of fiberless reference specimens can be modified in a way to exhibit relatively smaller displacement results after impact loading without risking the basic mechanical properties and deflection-hardening response with multiple cracking. © 2019 fib. International Federation for Structural Concrete
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    Seismic assessment in a historical masonry minaret by linear and non-linear seismic analyses
    (Budapest University of Technology and Economics, 2020) Hökelekli E.; Demir A.; Ercan E.; Nohutçu H.; Karabulut A.
    Operational Modal Analysis (OMA) method is frequently used in order to determine dynamical properties of historical masonry structures. In this study, damage pattern of historical Alaca minaret which is selected as application is investigated under different ground motions by updating finite element models (FEM) depending on operational modal analysis test. Initial Finite element model was prepared in ABAQUS V10 program and numerical dynamic characteristics of minaret were determined. In addition, experimental dynamic properties of minaret were provided by operational modal analysis. Initial numerical model of brick masonry structure was calibrated via OMA method. Then, linear and non-linear seismic analyses of calibrated FEM of historical minaret were performed by using different earthquakes acceleration records that occurred in Turkey. Concrete Damage Plasticity model was taken into account in non-linear seismic analyses. As a result of the analyses, it is concluded that the stresses obtained with linear analyses aren’t as realistic as the non-linear analyses results and the earthquakes can cause some damages in the minaret. © 2020, Budapest University of Technology and Economics. All rights reserved.