The Numerical Simulation Of Cure Process In Resin Transfer Molding

The development and research of advanced composite materials is one important direction of material science in the world now. Resin Transfer Molding(RTM) is the fast developing process for manufacturing fiber reinforced composite recently. The products of RTM have high quality, high dimension and shape precision. RTM can also make part-design for high performance, reduce production cost ,shorten production period and produce without volatile gas. RTM is widely used in aviation, mobile, construction, communication, sanitation, sports fields and so on.In the RTM process, a viscous resin is injected into a mold cavity containing a pre-placed fiber perform under certain temperature and pressure. After the infiltration of the resin into the empty spaces in the mold, the manufacturing process is characterized by a cuing reaction. The curing process is the key important part in RTM, which is an exothermic resin polymerization phenomenon that can cause temperature gradients and cure in no average in the composite, which leads to the residual stresses that cause shrinkage and warpage . So ,doing some research on the numerical simulation of curing process is meaningful to optimize the curing process and choose the right process variables.The main content of this paper is the numerical simulation of temperature and cure fields of cure process in RTM. According to chemical reaction kinetics theory, a mathematical model of cure process in RTM is built. Then, the numerical computation expressions of cure ratio and increment of cure ratio are constructed. Based on the chemical thermodynamics, handling the heat of cure reaction as internal heat source, the numerical expressions of the reactive calorific intensity and released heat of reaction are deduced. With the statistical crosslinking theory, the mathematical expression of cure ratio and crosslinking degree that satisfy gelation condition is established. Adopting the weighted margin method of the finite element theory, the foundational control equations for calculating the temperature field accompanied by cure heat are built by bringing in the thermal boundary conditions.