Pressure dependent modeling of thermoet epoxy-resins for theappllication in carbon composites

本提案的目的是研究压力对环氧树脂固化行为的影响，以及对最终复合材料部件的性能和工艺引起的变形的影响。这应通过材料特性的自由体积相关材料建模和考虑压力对自由体积的影响来实现。这样就实现了作用于树脂上的压力与其热化学性质之间的强耦合。这将回答一个潜在的研究问题：压力对环氧树脂固化行为的影响是否可以用自由进化理论来解释？该理论的一个应用是模拟高压RTM工艺，这是RTM工艺的一个变体，使用高达200bar的更高工艺压力。高压可以减少工艺周期时间，但在这种高压下，压力对材料性能的影响不能再被忽视，必须进行建模，以便进行工艺模拟。研究将对陶氏公司的典型材料veraforce 5200树脂系统进行研究，这是一种专门为高压RTM开发的快速固化环氧树脂。关于环氧树脂在高压下的行为和固化行为的建模的发现将转移到其他材料。

The objective of this proposal is the investigation of pressureinfluence on the curing behaviour of epoxy-resins as well as on theproperties and process-induced distortions of the final composite part.This shall be achieved by a free-volume dependent material modellingof the material properties and the consideration of pressure influenceon free volume. Thereby a strong coupling between the pressureacting on the resin and its thermo-chemical properties is achieved.This will answer the underlying research question: Can the effect ofpressure on the curing behaviour of epoxy resins be explained by freevolume theory? An application for the developed theory is thesimulation of the high pressure RTM process, a variant of the RTMprocess using higher process pressures of up to 200 bar. The highpressure allows a reduction of process cycle times, but with this highpressures the pressure influence on material properties can no longerbe neglected and have to be modelled in order to perform processsimulations. Investigations will be done on an exemplary material, theVERAFORCE 5200 resin system by Dow, which is a fast curing epoxyresin specifically developed for high pressure RTM. The findingsabout the behaviour of epoxy-resins under high pressures and themodelling of the cure behaviour will be transferable to other materials.