Abstract
The paper presents the development of a cross-ply composite material reinforced with carbon fibers and epoxy matrix (CFRP). Specimens cut from composite plate have been tested in tensile, using a testing machine with hydraulic grips, assisted by full-field strain measurements equipment. Using tensile tests and ultrasounds technique, were determined the nine elastic characteristics of the orthotropic material. During tensile test, at a certain level of stress, inside the specimen, small cracks appear. These cracks become more numerous and larger with increasing of stress. A portion of a specimen without cracks and with cracks respectively, subjected to tensile, were simulated by Finite Elements Analysis (FEA). For this analysis, the composite material was considered homogeneous and orthotropic. The simulation of cracks presented inside the specimens at different stress levels has been realized using X-ray pictures. Based on the FEA determinations, the stress state in the vicinity of the cracks was determined.
Keywords: carbon fibers; laminate; matrix cracking; finite element analysis (FEA)