Tamer Özben

An elastic-plastic stress analysis of a woven reinforced steel fiber thermoplastic composite cantilever beam subjected to transverse uniform loads on the upper surface

In this study, an elastic-plastic stress analysis is carried out for a thermoplastic cantilever beam. This composite beam consists of woven Cr-Ni steel fibers and a low-density homogeneous polyethylene matrix, and is loaded uniformly. The Tsai-Hill yield theory is used for an analytical solution. The expansion of the plastic region and the residual stress component of x are determined for 0, 15, 30, 45, 60, and 90 orientation angles. The 45 orientation angle, which gives symmetrical values, represents the mean reinforcement angle because of the reinforcement type. The plastic region starts at the upper surface of the beam for 30 orientation angle. The intensity of the residual stress component of x is maximum at the upper and lower surfaces of the beam.

An elastic-plastic stress analysis in a unidirectional reinforced steel fiber thermoplastic composite cantilever beam loaded by a single force at the free end

In this study an elastic-plastic analysis is carried out in a unidirectional reinforced thermoplastic composite cantilever beam loaded by a constant single force at its free end. The composite beam consists of stainless steel fiber and low-density homogeneous polyethylene matrix. An analytical solution is performed for satisfying both the governing differential equation in the plane stresses case and boundary conditions for small plastic deformation. The composite material is assumed to be hardening linearly. The Tsai-Hill theory is used as a yield criterion. The intensity of the residual stress components of x is at the maximum at the upper or lower surfaces of the beam.

İKİ EKSENLİ YÜKLENMİŞ VE ORTASINDA ELİPTİK DELİK BULUNAN PLAKANIN DELİK GEOMETRİSİNE VE EĞİMİNE GÖRE GERİLME YOĞUNLUĞU FAKTÖRÜNÜN HESAPLANMASI

Sonlu bir plaka da bulunan delik v.b. sureksizlikler gerilme altinda iken delik civarinda daha fazla gerilmeyigilmasina neden olmaktadir. Iki eksenli gerilme durumu icin plakadaki farkli gerilme oranlarina gore gerilmeyogunlugunun degisimi elde edilmistir. Elips deligin uzun kenar (2b) ve kisa kenar (2a) uzunluklarina gore plakayuzeyinde meydana gelen gerilme alani dagilimi gosterilmistir. Ayrica, farkli gerilme oranlarinda elips deligin(2a) kenar uzunlugunun plaka genisligine gore (H) maksimum gerilme degerleri sonlu elamanlar yontemikullanilarak hesaplanmistir. Plaka x-eksenine gore, elips deligin egimine gore (θ= 00,150, 300, 450 ve 900)plakada meydana gelen gerilme yogunlugu ve alan degisimi arastirilmistir.

Düşey Yükleme Altında Kompozit Tabakalı Bir Plakanın Sonlu Elemanlar Yöntemi İle Plastik Bölge Genişlemesinin ve Oluşan Gerilmenin Analizi

The aim of this work is to predict the expansion of the plastic zone and residual stresses in layers of stainless steel woven fiber-reinforced thermoplastic matrix composite laminated plates (( 0 /- 0 )2) with rectangu- lar hole. The elastic and elastic-plastic stresses are analyzed by using FEM by means of a developed computer program with FORTRAN 90. The laminated plates arranged in (( 0 /- 0 )2) configuration under uniform trans- verse loading are formed by stacking four composite layers bonded symmetrically or antisymmetrically. Loading is gradually increased from yield point of the plate as 0.0001 Mpa at each load step. The elastic, elastic-plastic and residual stress components and the expansion of the plastic zones are obtained according to the load steps, different orientation angles and rectangular hole dimensions under clamped and simply supported boundary conditions. Results showed that the maximum stress levels and the plastic zones appear the vicinity of the rec- tangular hole at the upper and lower layers.