Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
Browse
2 results
Search Results
Article Constitutive Equation Determination and Dynamic Numerical Modelling of the Compression Deformation of Concrete(Wiley, 2021) Seven, Semih Berk; Çankaya, M. Alper; Uysal, Çetin; Taşdemirci, Alper; Saatci, Selçuk; Güden, MustafaThe dynamic compression deformation of an in-house cast concrete (average aggregate size of 2-2.5 mm) was modelled using the finite element (FE), element-free Galerkin (EFG) and smooth particle Galerkin (SPG) methods to determine their capabilities of capturing the dynamic deformation. The numerical results were validated with those of the experimental split Hopkinson pressure bar tests. Both EFG and FE methods overestimated the failure stress and strain values, while the SPG method underestimated the peak stress. SPG showed similar load capacity profile with the experiment. At initial stages of the loading, all methods present similar behaviour. Nonetheless, as the loading continues, the SPG method predicts closer agreement of deformation profile and force histories. The increase in strength at high strain rate was due to both the rate sensitivity and lateral inertia caused by the confinement effect. The inertia effect of the material especially is effective at lower strain values and the strain rate sensitivity of the concrete becomes significant at higher strain values.Article Citation - WoS: 3Citation - Scopus: 5The Effect of Strain Rate on the Mechanical Behavior of Teflon Foam(Elsevier Ltd., 2012) Taşdemirci, Alper; Turan, Ali Kıvanç; Güden, MustafaThe quasi-static (1 × 10−3, 1 × 10−2 and 1 × 10−1 s−1) and high strain rate (7200 and 9500 s−1) experimental and high strain rate numerical compression deformation of a Gore Polarchip™ CP7003 heat insulating Teflon foam was investigated. High strain rate tests were conducted with the insertion of quartz crystal piezoelectric transducers at the end of the transmitter bar of a compression Split Hopkinson Pressure Bar (SHPB) set-up in order to measure the force at the back face of the specimen. A fully developed numerical model of the SHPB test on Teflon was also implemented using LS-DYNA. The simulation stresses showed close correlations with the experimentally measured stresses on the bars. The developed model successfully simulated the high strain rate loading. The damage initiation and progression of experimental high strain rate tests were further recorded using a high speed camera and found to be very similar to those of the simulation high strain rate tests.