Research on Anisotropic Viscoelastic Constitutive Model of Compression Molding for CFRP

Abstract

The carbon-fiber-reinforced polymer (CFRP) is a mainstream material for lightweight products from the end of the 20th century to the present day. Its compression molding process has obvious advantages in mass production. This paper attempts to establish the constitutive models of compression molding of the CFRP materials and study their mechanism. Based on anisotropic linear elastic mechanics, viscoelastic mechanics, and thermodynamics, as well as the Maxwell viscoelastic constitutive model, we first establish the constitutive model of thermorheologically simple CFRP materials (TSMs). Then, considering the influence of temperature on the initial stiffness and equilibrium stiffness, the concept of temperature stiffness coefficient is introduced, and the Cartier coordinate system is converted into a cylindrical coordinate system, thereby establishing the constitutive model of thermorheologically complex materials (TCMs) using the tensor form. Finally, by comparing to the structure of the Zocher model, the two constitutive models established in this study are verified. The research findings have important theoretical research significance for studying the compression molding mechanism of carbon fiber and further improving the quality of product molding.

Mechanism of curing behavior for CFRP compression molding under thermo-mechanical-chemical multi-field coupling

“…The material attributes of the matrix and the reinforced fibers are needed to simulate the curing process of the CFRP. Based on the thermal conduction equations (14)(15)(16)(17)(18)(19)(20) in the mathematical models, the thermal physical parameters of the matrix and the reinforced fibers are listed in Table 1.…”

“…Considering the thermal-chemical effect during polymer curing, Min Rong et al [16] predicted curing deformation of polymers, in the light of the viscoelastic features of the resin matrix. The author [17] took account of the influence of temperature on initial stiffness and equilibrium stiffness, established the anisotropic constitutive model of the curing process, and effectively forecasted the temperature field and curing field through the curing process.…”

Carbon Fiber Reinforced Polymers

“…Wang et al [ 28 ] critically reviewed the elastoplastic micromechanics models of composites and compared them in the case of the elastoplastic behavior of long fibrous composites subjected to a static load. Xie et al [ 29 ] studied anisotropic viscoelastic constitutive models of compression molding for CFRP.…”