Experimental study of the cocure process with the vacuum bag method for honeycomb sandwich structure

By using glass fiber/ epoxy 648 as panel and Nomex honeycomb as core , the effect s of resin flow behavior on the area of fillet and panel quality in the honeycomb sandwich st ructure were investigated with the vacuum bag cocure process , and the relationships between bonding st rength and fillet area were discussed by testing
the flatwise tensile st rength of samples. It is found that the fillet area first increases then decreases as the application time of vacuum is put off . The fillet area between bot tom panel and honeycomb core is larger than that between top panel and honeycomb core. As resin viscosity varies , the mechanisms of porosity elimination change , which can also be influenced by the dist ribution of gas passage in the sealed bag. Moreover , the result s of the mechanical test show that the improvement of flatwise tensile st rength can be achieved by increasing the fillet area. However , if the bonding st rength surpasses the tensile st rength of the honeycomb core , it has limitation to characterize the bonding property by the flatwise tensile st rength.