Ömer Yavuz Bozkurt

Investigation of RPIM Shape Parameter Effects on the Solution Accuracy of 2D Elastoplastic Problems

The effects of radial point interpolation method (RPIM) shape parameters on the solution accuracy of 2D elastoplastic problems are investigated. The RPIM algorithm is adapted for the solution of 2D elastoplastic problems using the multi-quadric radial basis function. The convergence rates after yielding are investigated for perfectly plastic and hardening cases with various shape parameters. Both regular and irregular node distributions are used by considering the standard Gauss integration and nodal integration schemes. It is shown that the solutions after yielding can be improved using appropriate shape parameters. The propagation of plastic region and solution time of each case are presented against load increments.

Damping and vibration characteristics of basalt-aramid/epoxy hybrid composite laminates

Abstract Damping and vibration characteristics of basalt-aramid/epoxy hybrid composites with different basalt/aramid fiber mixing ratios were investigated. Unidirectional basalt and twill weave aramid fibers were used as reinforcement. Non-hybrid basalt/epoxy and aramid/epoxy composite laminates were also fabricated for comparison. Dynamic characteristics of the composite laminates were determined experimentally using dynamic modal analysis. Damping properties were calculated with the logarithmic decrement method using a vibration response envelope curve. Loss modulus, storage modulus and damping ratio of the structures were also considered. It was observed that the results of hybrid configurations showed a distribution between non-hybrid basalt/epoxy and aramid/epoxy composites. Furthermore, the employment of aramid fibers in composite laminates enhances the damping properties of laminates, but reduces the strength values.

Yapıştırma ile Birleştirilmiş Cam Elyaf Takviyeli Kompozit Tabakaların Sönümleme ve Titreşim Davranışları

Son zamanlarda, elyaf takviyeli kompozit malzemeler ustun mekanik ozelliklerinden dolayi yapisal uygulamalarda yaygin olarak kullanilmaktadir. Yapi bilesenlerinin sisteme dahil olmasi icin bir yontem gerekmektedir. Son yillarda yapistirma ile birlestirme yontemi uretim ve kurulum kolayligindan dolayi dikkat cekmektedir. Bu calismada cam elyaf takviyeli kompozit tabakali plakalarin sonumleme ve titresim davranislari tek takviyeli bindirme baglantisi kullanilarak birlesim uzunluguna gore arastirilmistir. fiber yonelimlerine sahip alti simetrik tabakadan olusan plakalar dort farkli birlesim uzunlugunda deneysel olarak incelenmislerdir. Kompozit plakalarin titresim ozellikleri dinamik model analizi yapilarak belirlenmistir. Sonumleme ozellikleri titresim tepkisi egrilerinden alinan sonuclarin yarim bant genislik yontemini kullanmak sureti ile elde edilmistir. Elde edilen sonuclar birlestirme yapilmamis kompozit tabaka ile karsilastirilmistir.