Design For Composite Truss With Long Span And Mechanism For Setting Up And Dismantling Quickly

An integrated structure of the composite truss with long span was ascertained by the means of numberical analysis. A finite element model of the truss was established by ANSYS. Main loading which the truss might suffer were ascertained. The maximum displacement and the distribution of stress for the truss were computed under different loads. The computed results show that the stability, mechanical performance of the truss met with the use conditions. The modularized structure element, joint type, fixing and dismantling process of the long span composite truss were designed. A method of fixing and dismantling for the long span composite truss was validated by testing a steel truss with the equivalent stiffness to the composite truss. The results show that the method of fixing and dismantling the composite truss was feasible.By applying side and vertical loads to a single arch steel truss, the relationship between the side, vertical displacement and the loads was ascertained. The test results were believable. A finite element model for two steel/composite pipes connected by a composite pipe joint was developed with ANSYS software. With the functional module of contact element in ANSYS, the stress distribution in the composite pipe joint under different contact conditions to the steel/composite pipes (bending, compression and torsion) were obtained, and the load bearing capability of the composite pipe joint were further studied. The studies are focused on effects of friction coefficient on the friction stress on the contact surfaces between the steel/composite pipe and the composite pipe joint, and effects of the friction stress on the load bearing capability of the composite pipe joint. The results show that, with increasing of friction coefficient, the maximum contact pressure between the composite pipe joint and the steel pipe decreases and the maximum friction stress increases; the load bearing capability of the composite pipe joint is strengthened under the bending.With the functional module of optimization design in ANSYS, the wall thickness of the composite pipe joint was optimized. The results show that, under combined loads in which bends is primary, the optimization wall thickness of the composite pipe joint decreases with the increasing of friction coefficient. The optimization wall thickness was more sensitive to compression than to torsion.A finite element model for a T-type joint was developed with ANSYS software. With contact element in ANSYS, the stress distribution in the composite T-type joint under bend were obtained, and the load bearing capability of the composite T-type joint were further studied. The studies are focused on effects of friction coefficient on the friction stress on the contact surfaces between the composite pipe and the composite T-type joint, and effects of the friction stress on the load bearing capability of the composite T-type joint. The results show that, with the increasing of friction coefficient, the maximum contact pressure between the composite T-type joint and the composite pipe increases a little and the maximum friction stress increases; the load bearing capability of composite T-type joint is weakened under bend.