模具材料对复合材料制件固化过程应变的影响分析

复合材料热压罐固化工艺过程中,制件的固化变形依旧是影响成形质量的重要原因。通过光纤光栅和热电偶相结合的方法对复合材料制件在热压罐成形工艺过程中的温度和应变进行在线监测,研究了树脂基体对制件应变的影响规律,并基于此分析了不同模具材料对制件固化过程应变和固化变形的影响。试验结果表明:树脂与模具是复合材料固化过程应变变化的主要影响因素,在升温/保温阶段,树脂的流动、热膨胀、固化反应等是应变变化的主要原因,而在降温阶段模具收缩对应变变化起主导作用;不同模具材料的刚度、与制件的结合能力以及热膨胀系数的变化会在复合材料固化过程的不同阶段对应变变化产生较大影响。本文获得了不同材质模具试验条件下复合材料制件固化过程中的应变曲线,分析了固化过程中模具对复合材料制件内部应变的影响规律,为深入分析大型复合材料构件固化变形提供了理论支撑。

Influence of mould materials on curing process and deformation of composite part

During the curing process of composite in autoclave, the curing deformation of the workpiece is still an important factor affecting the quality of forming. By using fiber Bragg grating and thermocouple sensors, the temperature and strain of composite part are monitored on line during the autoclave curing process. The influence law of resin matrix on strain in part is studied, and based on this, the influence of different mould materials on strain in composite curing process is analyzed. Experimental results show that resin and mould are the main influence factors of strain variation in composite materials curing process: On temperature rising and holding stage, the strain variation is caused by the resin flow, thermal expansion and curing reaction, while the mould contraction will contribute most to the strain variation on the cooling stage. The change of stiffness, binding capacity with parts and thermal expansion coefficients of different mould materials will affect the strain variation in different stages of composite curing process. The curing strain curves of composite material parts under the curing process with different material moulds are obtained, the influence of different mould materials on strain in composite curing process is analyzed, and the conclusions have instruction significance to large composite parts curing deformation for further analysis.