Modeling and investigation of ballistic damage of the composite plates subjected to aging process with finite element method

Fiber-reinforced composite materials, which are widely used in ballistic applications, deteriorate over time due to various aging processes. Determining the mechanical properties of composite materials that deteriorate due to aging is important for use in practice. It has been seen in the literature that composite materials subjected to various aging processes have been examined experimentally, theoretically or by finite element methods. However, no study has been found on the gradual damage examination of composite materials aged in artificial seawater using the finite element method. For this reason, in this study, gradual damage examination of the S2 glass/epoxy composite material aged in artificial seawater environment was carried out using the Ls dyna and Mat 162 material model. In the first stage of the study, S2 glass/epoxy composite plates were produced and the produced plates were cut in accordance with the standards and test samples were obtained. Cut samples, It is divided into four groups: one group for those who are not aged and 3 groups for those who are subjected to aging (4, 8 and 12 months). The samples obtained were subjected to aging in an artificial seawater environment. The mechanical properties of the material were determined through tests applied to all samples. In addition, a draft version of the Mat 162 material model parameters was obtained using data obtained from mechanical tests and literature (Based on the literature for the first group and the data of the previous group for the other groups). Finite element analysis of the tests were performed with the obtained Mat 162 material model parameters. By comparing the analysis and test results, Mat 162 material model parameters were obtained for both aged and non-aged groups. Due to the effect of the aging process on the material, a decrease was detected in other Mat 162 material model data, except for the "am and density" parameters. Finite element analysis for ballistic application was performed with the Mat 162 material model parameters obtained for all groups. According to the analysis results, it was determined that ballistic resistance decreased as the aging time increased. In addition, curve equations depending on the aging time were obtained for the Mat 162 material model parameters affected by the aging process of the groups. By using these equations, Mat 162 material model data determinations can be made for the aging process lasting more than 12 months.