Unidirectional Fiber-reinforced Polymer Matrix Research Articles

Determination of Material Parameters for Microbuckling Analysis of Fiber Reinforced Polymer Matrix Composites

This research focuses on studying the effect of the constitutive law adopted for a matrix material on the compressive response of a unidirectional fiber reinforced polymer matrix composite. To investigate this effect, a periodic unit cell model of a unidirectional composite with an initial fiber waviness and inelastic behavior of the matrix was used. The sensitivity of the compressive strength to the hydrostatic pressure, the flow rule and the fiber misalignment angle were presented. The model was verified against an analytical solution and experimental data. Results of this study indicate that a micromechanical model with correctly identified material parameters provides a useful alternative to theoretical models and experimentation.

Plastic Deformation of Fiber Coating in Polymer Matrix Composites under Hygrothermal Loading

This paper is concerned with the study of elasto-plastic deformation of the coating, and consequently, the changes in the states of stress in the constituent phases of a unidirectional fiber reinforced polymer matrix composite (PMC) under uniform thermal, hygral and hygrothermal loadings. A four-phase composite cylinder assemblage (CCA) model has been used for the analysis. The coating interphase between the fiber and the matrix has been taken to be of lower modulus and lower yield stress value than that of the matrix. Only those combinations of temperature and moisture content are considered which give rise to plastic deformation in the coating, other phases still remaining elastic. Plastic behaviour of the coating has been idealized by taking a linear work-hardening constitutive relation.