20. Ulusal Mekanik Kongresi
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ÖgeDispersion Of Lamb Waves Propagating In A Plate Made Of Viscoelastic Material(Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017)Lineer viskoelastik malzemelerden oluşan plakalarda Lamb dalgalarının dispersyonu incelenmiştir. Araştırmalar, lineer viskoelastik teorisinin kesin denklemlerini uygulayarak yapılmıştır. Dispersyon denklemi, malzemenin herediter operatörünün keyfi türü için elde ettikten sonra incelenen dalgaların dispersyonu üzerine sayısal sonuçlar elde etmek için bir çözüm algoritması geliştirilmiştir. Farklı atenüasyon durumları için dispersyon eğrileri elde edilmiş ve malzemenin viskozitesinin etkisi, elastik sabitlerle karakterize eden reolojik parametreler, yani, Q viskoelastik malzemenin karakteristik akma süresi, d viskoelastik malzemenin mekanik sabitlerinin uzun vadeli değeri ve α viskoelastik malzemenin deformasyonun başlangıç durumu etrafındaki mekanik davranışı aracılığıyla incelenemiştir. Malzemenin viskoelastisitesini Rabotnov'un kısmi eksponansiyel operatörü’nü uygulayarak sayısal sonuçlar sunularak tartışılmıştır. Özellikle, reolojik parametrelerin, incelenen plakada yayılan Lamb dalgalarının dispersyonuna nasıl etkilediği tespit edilmiştir.
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ÖgeForced Vibration Of The Hydro-viscoelastic (hydro-elastıc) Systems Consisting Of The Viscoelastic (elastic) Plate, Compressible Viscous Fluid And Rigid Wall (review)(Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017)This paper gives review of the investigations related to the forced vibration of the hydro-viscoelastic as well as of the hydro-elastic systems consisting of elastic or viscoelastic plate, compressible viscous fluid and rigid wall. The sketch of this system in some particular case is given in Fig. 1. The investigations carried out for the fluid loading cases are also reviewed and under this review the main attention is focused on the studies made by authors. Note that in these investigations the motion of the plate is written by employing three-dimensional linearized equations of wave propagation in elastic and viscoelastic bodies with initial stresses, however the equations of flow of the compressible viscous fluid is described by employing the linearized Navier-Stokes equations. It is assumed that the plane strain state in the plane occurs in the plate and the fluid flow is plane-parallel one and suppose that the plate occupies the region Within these assumptions we write the field equations for the constituents of the system in the case where the plate material is purely elastic.
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ÖgeTwo-way Shear Behavior Of Concrete Slabs Reinforced With Polypropylene Fibers(Theoretical and Applied Mechanical Turkish National Committee, İTÜ, 2017)
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ÖgeA Simplified Prediction Approach For Localized Unstable Springback Due To Oil Canning Effect(Theoretical and Applied Mechanical Turkish National Committee, İTÜ, 2017)Dimensional precision is a major key factor for robust automated production. Springback is one of the most important effect to reduce part geometry level. Also unpredictable springback such as oil canning effect which has eliminates compensation possibilities to ensure part geometry. In this paper the prediction of oil canning effect in forming simulations is presented. Simple prediction approach with clamping forces have been investigated and compared with real measurements.
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ÖgeCqnls Equation: Comparison Of Analytical And Numerical Solutions(Theoretical and Applied Mechanical Turkish National Committee, İTÜ, 2017)In nonlinear optics, the propagation of electromagnetic waves in photorefractive materials with intrinsic nonlinear resonance can be modelled by the nonlinear Schr odinger (NLS)equation containing both cubic and quintic terms [1].This study deals with the soliton solutions of the (1+1)D cubic-quintic nonlinear Schr odinger(CQNLS) equation. First, analytical solutions are calculated for di erent media. Then,solutions are obtained numerically and compared with their analytical counterparts.