Publication: Elyaf sarma yöntemiyle üretilen karbon elyaf kompozitlerde ön gerilme parametrelerinin elyaf ve kompozit mukavemetine etkisi
Abstract
ELYAF SARMA YÖNTEMİYLE ÜRETİLEN KARBON ELYAF KOMPOZİTLERDE ÖN GERİLME PARAMETRELERİNİN ELYAF VE KOMPOZİT MUKAVEMETİNE ETKİSİ Bu çalışmada, elyaf sarma makineleri ile karbon elyaf takviyeli kompozitlerin üretimi esnasında, sürekli karbon elyafın mekanik özelliklerindeki değişim teorik ve deneysel olarak araştırılmıştır. Özellikle karbon elyaf takviyeli ürün tasarımı için karbon elyafın mekanik özelliklerinin tahmini çok önemlidir. Elyaf sarma teknolojisi ile kompozit ürünlerin üretiminde üretim esnasında öngerilme parametrelerinin iyi ayarlanması çok önemlidir. Elyaf sarma makinelerinin öngerilme sistemi, ön gerilmenin kolaylıkla ayarlanabilmesi için hareketli birkaç alüminyum makara ve devir kontrollü motordan oluşur. Karbon elyaflar kırılgan yapıları nedeniyle eğilme kuvvetlerine karşı çok hassastır. Makaralar arasındaki açı ve elyafa uygulanan ön gerilme yükü, elyaf üzerindeki eğilme gerilmelerini belirler. Makaralar arasındaki açı küçüldükçe, elyaf demetindeki elyafların kırılmasına neden olan eğilme gerilmeleri artar. Elyaf sarma makinelerindeki ön gerilme sisteminin benzerini oluşturmak için PI kontrollü bir deney düzeneği tasarlanmış ve üretilmiştir. Deneyler sonucunda, sürekli karbon elyafın çekme mukavemetinin % 10 – 43 arasında azaldığı belirlenmiştir. Ayrıca deneysel sonuçlara göre, elyaf sarma işleminde karbon elyafların mekanik özelliklerindeki azalmanın tahmini için istatistiksel bir model önerilmiştir.
THE EFFECT OF PRETENSION PARAMETERS ON THE MECHANICAL PROPERTIES OF THE CARBON FIBER REINFORCED COMPOSITE OBTAINED BY FILAMENT WINDING TECHNOLOGY The change of mechanical properties of continuous carbon fiber during manufacturing process of carbon fiber reinforced composites in filament winding machines are investigated theoretically and experimentally in the present study. The prediction of the mechanical properties of the carbon is very important especially to make the right Carbon Fiber Reinforced Composite (CFRP) part designs. Pretensioners which are an important part of manufacturing process to produce composite mechanical parts in filament winding should be well adjusted during the manufacturing process. Pretension systems in winding systems consist of several moveable aluminum rollers and a torque controlled motor, so that the tension in the continuous fiber can be adjusted easily. Carbon fibers are very sensitive to the bending forces since they are very brittle. The angle between the roller and the amount of the torque applied to the fiber defines the magnitude of the bending stresses on the fiber. As the angle between the rollers decrease, the fiber undergoes more bending stresses which causes an increase in fiber breakage on the fiber bundle. A PI controlled experimental system has been designed and manufactured to simulate the pretensioning in the filament winding machine. Experimental results indicate that the tensile strength of continuous carbon fiber is reduced by 10 – 43 %. Also, a formulation based on the statistics of the experiments has been proposed to predict the strength reduction of the carbon fibers during pretensioning in the filament winding manufacturing process.
THE EFFECT OF PRETENSION PARAMETERS ON THE MECHANICAL PROPERTIES OF THE CARBON FIBER REINFORCED COMPOSITE OBTAINED BY FILAMENT WINDING TECHNOLOGY The change of mechanical properties of continuous carbon fiber during manufacturing process of carbon fiber reinforced composites in filament winding machines are investigated theoretically and experimentally in the present study. The prediction of the mechanical properties of the carbon is very important especially to make the right Carbon Fiber Reinforced Composite (CFRP) part designs. Pretensioners which are an important part of manufacturing process to produce composite mechanical parts in filament winding should be well adjusted during the manufacturing process. Pretension systems in winding systems consist of several moveable aluminum rollers and a torque controlled motor, so that the tension in the continuous fiber can be adjusted easily. Carbon fibers are very sensitive to the bending forces since they are very brittle. The angle between the roller and the amount of the torque applied to the fiber defines the magnitude of the bending stresses on the fiber. As the angle between the rollers decrease, the fiber undergoes more bending stresses which causes an increase in fiber breakage on the fiber bundle. A PI controlled experimental system has been designed and manufactured to simulate the pretensioning in the filament winding machine. Experimental results indicate that the tensile strength of continuous carbon fiber is reduced by 10 – 43 %. Also, a formulation based on the statistics of the experiments has been proposed to predict the strength reduction of the carbon fibers during pretensioning in the filament winding manufacturing process.