Simulation analysis of a foldable carbon fiber reinforced honeycomb sandwich composite bridge

Portable bridge is very important in the military for mobility. However, it becomes more important nowadays for disaster relief operations. In the early days, military bridges were made from steel causing the weight of the bridge to be huge, thus, need more vehicles to transport the bridge and crane with higher capacity to erect it. Subsequently it will cost more to operate. Aluminum and metal alloy were introduced to reduce the weight of such structure to overcome these problems. Then new material emerge called composite material, i.e. Carbon Fiber Reinforced Polymer (CFRP) and honeycomb material which is usually used for sandwich structure. CFRP and aluminum honeycomb are being considered to be used as a primary material for the portable bridge. The reason to use the CFRP as a primary material is due to its high strength to weight ratio, thus making it lighter than steel and other alloy. The use of honeycomb is expected will increase the stiffness of bridge beam without additional weight significantly. In this study one layer of CFRP is called as lamina and the stacking of lamina is called as laminate. Aluminum Honeycomb Hex-Web 5.2-1/4-25(3003) is used as the core in this study, while laminate is used as the skin for sandwich structure of the beam. The laminate is consisting of 31 to 49 plies of lamina, where the lamina thickness is 0.815 mm that produces the laminate thickness from 25 to 40 mm. The thickness of aluminum honeycomb which is used is in the range of 50 to 300 mm that produces sandwich structure thickness from 85 to 340 mm. Finite Element Analysis (FEA) is used due to unavailability of standard for design of structure using CFRP and honeycomb. Maximum stresses and also the possibility of buckling on the structure have been investigated. Several trials are made to test several lay-up of lamina including use of aluminum honeycomb core to increase stiffness of the member. The trials produce the maximum stress on the lamina in fiber direction is 104 MPa (compression) , while the maximum stress in perpendicular to fiber direction and shear stress are 4.02 MPa (compression), and -7.44 Mpa, respectively.. The use of failure formulations which is shown in the form of graphic shows that the lamina stresses is in allowable range. The maximum stress of Aluminium honeycomb in zdirection is 0 MPa, while the shear stress in y-z and x-z planes are -0.844 Mpa and 1.45 Mpa, respectively. The maximum stresses of honeycomb are lower than the strength of honeycomb itself, it means that the aluminum honeycomb is able to support the load without failure. From the trials can be concluded that, with proper design Carbon Fiber Reinforced Polymer and Aluminum Honeycomb can take the design load similar to steel and aluminum