Analysis Method Lattice Jib 3S Reliability

In practical engineering structure, there are a lot of statically indeterminatestructures. When analyzing the structural system reliability， there will beexisted large amounts of failure mode. How to identify the main failure mode ofstructure system， the reliability of solving the main failure mode andcomprehensive main failure mode to solve the structural system reliability is themain content of this article research.Based on lattice boom as the research object, this article does the structuresystem reliability analysis. In the process of solving the lattice booms’ structuralsystem reliability, first of all, according to the type of lattice boom structuresystem of its own structural characteristics and mechanical characteristicsdetermine its corresponding system failure criterion, and do the qualitativeanalysis that the each failure criterion of the effect of the whole system. Thereare a lot of system failure modes, it through the branch threshold method toidentify the main failure mode of lattice boom structure system, and through theimprovement of branch threshold method to make it more suitable for latticeboom system structure, and main failure mode identification is more rapidaccurate. It save a lot of time and improve the efficiency of recognition.Both solving the reliability of structural components and reliability of themain failure mode of structure system, it need generate the safety marginequation and use the First-order Second-moment Method to calculate. Incalculating the whole lattice boom structure system failure probability, thePENT method is adopted. It is divided all the main failure modes into severalgroups which have their own representative failure mode and then through thefailure probability of representative failure modes to solve the whole structuresystem reliability.According to the above theory, based on VC++prepare the lattice boomstructure system reliability analysis software. This software can beparameterized calculation and checking the mechanical model of lattice boomstructure; it can automatically generate the APDL command flow of the parameterized analysis model of ANSYS; it can extract the whole stiffnessmatrix of lattice boom structure system and verify its singularity. Then itcombined with branch threshold method and PENT method to calculate thelattice boom structure system reliability.Based on the research of the structural system reliability theory, using theimproved branch threshold method and the method of PENT, it can greatlyimprove the computing efficiency of the lattice boom structure system reliability.Through preparing the lattice boom structure system reliability analysis software,it provides a new thought and approach for the calculation of reliability ofstructural system. The combination of theory and software will be laying afoundation for further development of the research of structural systemreliability.