Fuzzy Modeling the Influence of Fiber Volume Fraction and Strain Rate on Tensile Propertiesof Carbon/Epoxy Composites

In this research, a fuzzy logic was used in order todetermine the tensile modulus of epoxy resin reinforcedwith woven carbon fibers conceived as a lightweightmaterial for engineering applications. In polymer matrixcomposites, the mechanical properties such as tensilemodulus change with various factors. Two of the mostimportant factors are fiber volume fraction of compositeand test condition of strain rate. In this study,experimental program was conducted to determine thetensile modulus of carbon fiber reinforced epoxycomposites (CFE). Variations in tensile modulus of theCFE composites with respect to fiber volume fractionand strain rate were investigated. From the tests, theeffect of different three fiber volume fractions (۴۰, ۵۰and ۶۰) and two strain rates (crosshead speed of ۲ and ۶mm/min) on tensile behavior of CFE composites wasstudied. Then, with the fuzzy logic model prepared inMATLAB and using different membership functions andvarious linguistic variables, tensile values for CFEcomposites were predicted. Three memberships functionlow, medium, and high for fiber volume fraction and twomemberships function low and medium for strain rateused to demonstrate the different ranges of input fuzzyvariable. Four membership functions based onMamdani-type FIS were ranging from soft, medium, stiffand very stiff to demonstrate the tensile modulus of theCFE composites. Results of the developed fuzzy logicmodel were compared with the experimental results. Thecorrespondence between the model and the experimentsresults and high value of coefficient of correlation (R۲)indicated that the fuzzy model can be effectively usedfor predicting the tensile modulus in CFE composites.

Keywords:

Fuzzy logic model , Tensile modulus , Carbonfibers , Epoxy resin.