Experimental And Simulation Research On Hot Air Forming Of GLARE Laminates

Since the beginning of this century,industries such as aerospace and rail transit have entered a period of rapid development,and companies have increasingly higher requirements for the strength,corrosion resistance,and lightweight properties of materials used.Fiber metal laminate is a composite material composed of metal sheets and fiber materials alternately layered.Because of its light weight,high strength,impact resistance and flame retardancy,it is widely used in aerospace,rail transit and other fields.However,due to the different material properties of each layer of fiber metal laminates,problems such as delamination and cracking are prone to occur when using traditional forming processes.Therefore,seeking a new process to form fiber metal laminates has greater application value.Thermal air inflation is a process that uses the high-pressure space formed by gas to shape materials.It has the advantages of high efficiency,low cost,and simple mold structure.In this paper,the thermal inflating process is applied to the forming of GLARE laminates.The GLARE laminates are formed into a specific shape under a certain temperature and pressure.The formed laminates are cured by adjusting the temperature and pressure to achieve the production of GLARE laminates.Forming integration.The main research contents of the thesis are as follows:1.Through the finite element software,carry out the numerical analysis of hot air bulging and the exploration of the deformation law of the GLARE laminate.The law of the influence of temperature and pressure on the stress,strain,forming depth and wall thickness change rate of the specimen is obtained: at the same pressure Under the conditions,the higher the temperature,the greater the overall stress and strain of the specimen,and the greater the thickness change rate at the center of the specimen;under the same temperature conditions,the greater the pressure,the greater the overall stress and strain of the specimen,The greater the rate of thickness change at the center position.2.A special device for the thermal inflatable forming process of laminates was built to perform thermal inflatable forming of GLARE plates composed of 0.3mm and0.5mm thick 2024-T3 aluminum alloy and different types of glass fiber prepregs.The test results show that the GLARE board composed of 0.3mm 2024-T3 aluminum alloy and epoxy glass fiber prepreg has a good forming effect under the conditions of a forming pressure greater than 4MPa and a forming temperature of 110℃～140℃;0.3mm The GLARE board composed of 2024-T3 aluminum alloy and PP resin glass fiber prepreg has a good forming effect under the conditions of a forming pressure greater than 3MPa and a forming temperature of 170℃～200℃;0.5mm 2024-T3 aluminum alloy and PP resin The GLARE board composed of glass fiber prepreg has a good forming effect under the conditions of a forming pressure greater than 4MPa and a forming temperature of 170°C to 200°C.Through the test results,it can be concluded that the hot air bulge forming process can be used on GLARE laminates.3.The thickness of the formed test piece is detected by a thickness gauge.The thickness distribution from the center of the test piece to the edge position shows a trend of first increasing and then decreasing.The thickness at the center of the test piece is smaller than the thickness before forming,and the test piece is chamfered.The thickness is greater than the thickness before forming.The main reason for the uneven thickness distribution is the thinning of aluminum alloy and resin flow,and the position that is prone to cracking appears in the center of the thinnest thickness of the formed part.