Design, Manufacturing And Mechanical Properties Of Composites Honeycomb Sandwich Pipes

Composite honeycomb sandwich pipe is composed of an inner and an outer skin, abonding layer and a honeycomb core in the middle. It has been widely used as primarystructuras in aviation, aerospace and weapons due to high specific strength, highspecific stiffness and good buckling resistance performance. Meanwhile, it has excellentflexural stiffness and torsional stiffness, especially suitable for the large span structureswhich has a strict demanding of the structural weight and mechanical properties, such asa spar of wing structure. This paper mainly studied the structural design, manufacturingtechnology, flexural and torsional properties of the composite honeycomb sandwichpipe.Firstly, optimal design of the composite honeycomb sandwich pipe was conducted.The engineering constants of the unidirectional T300/F648epoxy and M40JB/F648epoxy composites were measured. By using finite element method with ANSYSsoftware, effects of the inner and outer skin thickness, angle of layers, layer sequenceand height of the honeycomb core height on the ratio of stiffness/mass of the carbonfiber composite honeycomb sandwich pipes were conducted. The final configuration ofthe composite honeycomb sandwich pipes was determined as followed: skin thicknessof1mm, the layers sequency of [0°/±30°/0°] and honeycomb core height of4mm.Secondly, manufacturing technology of the pipe was studied. Based on theinvestigation of the manufacturing process for the composite honeycomb sandwichpipes, the winding way, curing and demoulding technology was improved, and the finalmanufacturing process was determined and can be described as the manual prepregguiding, heat shrinkable tape pressurized solidification and the metal mandrel surfacecoated with butter and polyester film stripping process for decreasing friction. A4.2mlong composite honeycomb sandwich pipe was successfully fabricated by using thistechnology.Finally, mechanical properties of the composite honeycomb sandwich pipe weremeasured. The span for the flexural stiffness of composite honeycomb sandwich pipewas determined by finite element simulation, and it was found that the span should belarger than800mm. The flexural stiffness of the T300and M40JB carbon fibercomposite honeycomb sandwich pipes are1.495×1010N·mm2and2.357×1010N·mm2,respectively. The torsional stiffness of the T300and M40JB carbon fiber compositehoneycomb sandwich pipes are6.477×109N·mm2and1.070×1010N·mm2, respectively.