Study On Matrix Flow Behavior Of Phenolic Resin Thermal Protection Material During Winding Forming Process

Because of the characteristics of ablation resistance,high strength and heat resistance,phenolic resin thermal protection materials are widely used in thermal protection systems in aviation,aerospace and other fields.The transformation of phenolic resin thermal protection materials from raw materials to products is realized by forming and manufacturing,which is the prerequisite for the application of phenolic resin thermal protection materials.In order to improve the production efficiency and the mechanical properties of the products,phenolic resin thermal protection material is made into prepreg tape,which is formed into winding products to meet the design requirements by the winding forming process.Under the effect of winding process parameters,the viscosity of phenolic resin changes and flow behavior occurs,which changes the content and distribution of resin in the winding products,and affects the fiber volume content and interlaminar mechanical properties of the products.In this paper,the influence of process parameters on the flow behavior of matrix of phenolic resin thermal protection material and the mechanism of the influence of process parameters on the fiber volume fraction and interlaminar mechanical properties of the products were studied.The research content mainly includes the following points.Firstly,according to the characteristics of parallel winding,flat overlapping winding and oblique winding process of prepreg tape,the winding equipment suitable for these three kinds of winding process was designed.The cylinder forming and oblique winding experiments were carried out by using the designed winding equipment.And the winding preforms with good quality were obtained,which proved that the designed winding equipment could meet the requirements of winding process.Secondly,the heat conduction of phenolic resin thermal protection material during the winding forming process was analyzed,and the heat transfer models of prepreg tape in the winding process and winding layers in the curing process were established.According to the viscosity-temperature characteristics of phenolic resin,the effect of temperature rising rate on the curing degree of resin and curing time on the viscosity of resin were analyzed.Based on Maxwell model,the change process of resin under pressure was analyzed,and the relationship among temperature change rate,pressure and resin flow was obtained.Thirdly,based on the resin flow behavior under the effect of process parameters,the influence mechanism of static process parameters on the fiber volume fraction of products was experimentally studied by using the plate forming process of phenolic thermal protective material equivalent to the winding process.The numerical model between the process parameters and the fiber volume fraction of products was established,and the reliability of the model was verified.Fourthly,based on the flow behavior of the resin,the interlaminar bonding strength of the wound products under the coupling of process parameters was obtained experimentally,and the influence of the coupling of process parameters on the interlaminar bonding strength of the products was analyzed.In addition,the relationship between fiber volume fraction and interlaminar mechanical properties of the product under the influence of resin flow behavior was analyzed,and the change trend of fiber volume fraction and interlaminar bonding strength was basically consistent.The study on the flow behavior of matrix in the winding forming process of phenolic resin thermal protection material can provide theoretical reference for the selection of production process parameters and process control of phenolic resin thermal protective material products,and has a certain engineering application value in improving the properties and quality of products.