| Ultra-lightweight, high loading capacity of the truss structure made of CarbonFiber Reinforced Polymer (CFRP) is widely used in the aerospace field. Joints incomposite truss are very important in loading and transferring mechanicalproperties. In this paper, a new fusion joints made of joints and tubes in the trussstructure is proposed and studied. Against the joints, a new design method isproposed and the loading property is studied. The main work includes:Against the fusion joints, great effort is carried out to study the design methodof the fusion joint in composite truss. To calculate the transmission characteristics,the load cases of the composite truss are analyzed. Under the premise of meeting therequirement of the structure, the preliminary design is processed. The preliminarydesign concludes the material design, shape design, size design and the manufacturedesign. Then the strength of the joint is checked to determine the size of the designis reasonable.A new manufacture method made of manual winding and molded is designed.To make the fusion joints, manufacture process is formulated and the moulds aredesigned. The method can be used to the multi-planar composite tubes connect.Compared with the connect method that composite tubes is glued by joints, thismethod can solve the problem that residual stress is concentrated.To obtain the loading properties, this paper proposes a bend test method of thefusion joints, also builds a new test system. The load-displacement curves andstrain-time curves in key positions are gat. The failure load is8.7KN. The failuremode is split in constraint tubes. The maximum strain takes place in the tubes andjoints transition area.To study the loading properties in bend load and multi-axis load of fusionjoints, this paper builds the numerical model of the fusion joint, and then calculatesthe failure load on condition of the constraint and load condition. This papercorrects the model compared with the test results, and then studies the mechanicalproperty under bend load and multi-axis load. The influence rule of the mechanicalproperty in different layup conditions is analyzed.Results in this paper can provide a new thinking in multi-planar compositetube connect. They can also be used to provide the basis in design and analysis ofthe span truss. |
