Double cantilever indirect tension testing for fracture of quasibrittle materials

The Double Cantilever Beam (DCB) Mode I fracture testing has been widely used in fracture testing of especially fiber reinforced polymer composites and adhesive joints. Application of classical DCB testing to plain concrete or unreinforced ceramic specimens is not straightforward and cannot be carried out as in fiber reinforced polymer composites. Instead, an indirect tension approach is proposed in this study. Tests of notched geometrically similar DCB specimens made of normal and high strength concretes loaded eccentrically at the cantilever beam-column ends in compression have been carried out. Classical Type II size effect analyses of peak loads obtained from these tests are performed. The Microplane Model M7 is calibrated independently using uniaxial compression tests and employed to predict the peak loads of both tested and virtual geometrically similar DCB specimens. The same size effect analyses are performed on the predicted peak loads and the errors in the fracture parameters of the classical size effect analysis are determined.Peer ReviewedPostprint (author's final draft

Size effect tests of different notch depth specimens with support rotation measurements

Sener, Siddik/0000-0001-6659-5367WOS: 000372540700004Test results from a Type I & II size effect experimental study on notched and un-notched beams are presented in this paper. The test specimens were geometrically similar but had different scale ratios and different notch length ratios of 0, 0.02, 0.075, 0.15 and 0.3. The specimens had rectangular cross sections with constant thickness of 40 mm and the depth varied from 40 mm to 500 mm corresponding to a scale ratio of 1:12.5. Rotations measured at support locations for each specimen are presented to reinforce the experimental findings. It was observed that all specimens with different notch-to-length ratios exhibited size effect, in which the stress at maximum load (failure load divided by cross-sectional area) decreased as the size was increased. The results indicate that the failure is governed by fracture mechanics principles. This phenomenon is not addressed in current design codes, which do not account for such size effect. The test results showed that beams with shallow notch exhibit Type I, beams with deep notch exhibit Type II size effect law. The test results compared favorably with several widely accepted size effect models. (C) 2016 Elsevier Ltd. All rights reserved.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [111M374]; Gazi and Istanbul Bilgi UniversityGazi UniversityFinancial support from The Scientific and Technological Research Council of Turkey (TUBITAK), provided through Grant No: 111M374, and supports from Gazi and Istanbul Bilgi University is gratefully appreciated. Special thanks for helping are extended to Dr. Cagatay Mehmet Belgin, Res. Asist. Eren Yecan and Dr. Kadir Can Sener the planning and conducting the experiments

Vertical Displacements of Komurhan Bridge

WOS: 000368558200001In this study, displacements and stress distribution under vertical loads of Komurhan Bridge that is built by balanced cantilever method for the first time in Turkey were determined. For this purpose ANSYS software is used and the real behaviour of the bridge is created with the finite elements model by taking into account the material properties and the boundary conditions. The main span of the Komurhan Bridge is 143.50m, symmetric with prestressed box section whose end supports are located on the shore. The displacements obtained by the finite elements model of the bridge and those measured at the cantilever end under the truck load are found to be very close. The displacements, normal and shear stresses were obtained for the model which represents the real behavior of the bridge under excessive loadings. Excessive displacements, normal and shear stress at the critical cross sections are important for the safety of the bridge

Double cantilever indirect tension testing for fracture of quasibrittle materials

The Double Cantilever Beam (DCB) Mode I fracture testing has been widely used in fracture testing of especially fiber reinforced polymer composites and adhesive joints. Application of classical DCB testing to plain concrete or unreinforced ceramic specimens is not straightforward and cannot be carried out as in fiber reinforced polymer composites. Instead, an indirect tension approach is proposed in this study. Tests of notched geometrically similar DCB specimens made of normal and high strength concretes loaded eccentrically at the cantilever beam-column ends in compression have been carried out. Classical Type II size effect analyses of peak loads obtained from these tests are performed. The Microplane Model M7 is calibrated independently using uniaxial compression tests and employed to predict the peak loads of both tested and virtual geometrically similar DCB specimens. The same size effect analyses are performed on the predicted peak loads and the errors in the fracture parameters of the classical size effect analysis are determined.Peer Reviewe