Reliability Analysis Of Plate-Bar Structures System

The skin skeleton structure is widely used in the aeronautics and astronautics fields.In particular,the wing of an aircraft usually adopts a skin skeleton structure,which can be simulated by a plate-bar composite structure.The reliability of the wing is one of the important indicators to be considered when designing the aircraft.The reliability of the wing structure plays an important role in the performance and safety of the aircraft.Designing the reliability of the wing not only can significantly reduce the probability of a safety accident,but also enhance the performance of the aircraft,reduce the cost of design,and reduce the cost of maintenance.Therefore,structural reliability analysis has been widely used in the field of aircraft design.In this paper,the reliability analysis theory of element and structural system analysis are applied to the plate-bar structures,and the reliability analysis method of the composite plate-bar structures is given,which provides an effective method for system reliability analysis of the composite plate-bar structures.Firstly,the model of the wing is divided into finite element models.Equal strength contraints,constant strain triangular plate element and plane stress rectangular plate element is used to simulate the stringers,webs,wing ribs and skins of the wing box structure,which establish a more accurate finite element model.Program in the FORTRAN language and solve the finite element analysis of the wing box structure.Consider the uncertainty of the load and the mechanical properties of material.Using the stress intensity interference theory,the failure criterion is given,the inverse nodal forces of equal strengthcontraints,constant strain triangular plate element and plane stress rectangular plate element are derived.The safety margin equations of the above three elements are derived,and the second-order method is used to calculate the reliability of elements.And a method for simulating a structural system for using a series-parallel system is given.Then we use the advanced branch and bound algorithm to search for the main failure mode.The PNET method is used to calculate the system reliability index failure probability of the composite plate-bar structures.A method for effectively analyzing the reliability of the composite plate-bar structures is given.The above theory and method are self-programmed in FORTRAN language,and this program method can effectively calculate and analyze the reliability of the composite plate-bar structures.