Manufacturing and testing of a new CFRP node bonded by adhesives for its use in bus structures

In recent years exponential increase in the use of adhesives in industrial processes is observed. Nowadays these materials are used in applications as diverse as aerospace industry, automotive industry, railway industry or even civil construction. In the same way, the use of composite materials has grown enormously, especially in the aerospace industry, thanks to the benefits that this type of materials are able to provide, even as reinforcement. Current bus structures present serious problems of fatigue due to their rigidity, resulting in unexpected failures in certain nodes where stresses are concentrated. This work is part of a project that it is trying to provide more elasticity to the structure through the use of a new CFRP node joined by adhesives to the bus structure using polyurethane. The complex design of the node has caused numerous manufacturing problems. PLA node was manufactured using 3D printing for being used as a core. PLA node was covered layer by layer with CFRP by hand lay-up. In order to know the behavior of the whole set (CFRP node, adhesive and steel beams), four prototypes were manufactured and tested. Four point flexural test was carried out on the prototypes to validate the assembly. Results show the suitability and capacity of this new node concept to be used in bus structures.