Development And Study On The Properties Of Sandwich Composite Functional Panels 

High-strength polyester filament was used to manufacture woven spacer fabric in this paper. Stainless filaments were added to the woven fabric in order that the fabric gains certain electromagnetic shielding function. Electromagnetic shielding sandwiches composite panels were developed by filling foam materials in the space of the spacer fabrics and coating resin on the two faces of the fabrics. The performance of the function panels were tested and analyzed, including shielding effectiveness, fire-retardant properties and mechanical properties.Stainless steel fiber and polyester filament yarn is used to weave fabric in order to get some different spacer fabrics with the varying amounts of stainless steel fibers. Rigid polyurethane foam was selected to fill the spacer fabric and epoxy resin was chosen to coat the surface.to prepare the sandwich function panels.Various flame retardant agents were chosen to study the flame retardant property of the panels. A kind of panel was obtained by adding agents into the foam material and resin through a series of experiments Mechanical properties of the functional panels and general panels were compared. The testing results showed that the ammonium polyphosphate added to the polyurethane reduces the compression properties of the panels and cyclic phosphate coated surface improves the performance resistance to bending of the panels.Before shielding effectiveness test of the panels, the flange coaxial device was improved. The key to the modified equipment was the design of the sample holder and a long cylinder with retractable active was designed to meet the test requirements for different thickness of panels. The results of shielding effectiveness showed that the panels with stainless steel fibers get better shielding effectiveness in the range of high frequencies, so it has a very practical in daily life. This study also found that the height of sandwich composite panels has little impact on the shielding effectiveness of the panels.The deference of Mechanical properties between the functional composite panels and general polyester panels were analysised by testing the compression, bending, shear and peel performance of all kinds of samples. The results are that adding appropriate amount of stainless steel filaments can improve the mechanical properties of the panels to some extent. But the addition of the stainless steel filaments limited the resin penetrating into the face fabric. Meanwhile binder yarn containing many stainless steel fibers restricts the dispersion of foam. These factors have a synergistic effect on the integrity of the panels. The results of the impact test showed that the extent of the damage became more serious with the increase of the impact energy. Composite panels showed no obvious damage when subjected to low-energy impact. However, in this case the integrity of the panels has been destroyed according to the energy absorbed analysis of the sandwich panels. The invisible damage is very important to restrict the application of the sandwich multifunctional panels.