Finite Element Analysis of Inter Spar Ribs of Composite Wing of Light Transport Aircraft against Brazier Load

Inter spar ribs of wing of a transport aircraft is ubjected to various types of loads. One of the loads that poses stability problem to the interspar ribs of a wing is brazier load, which arises due to flexure of the wing. This paper describes about the finite element analysis of inter spar ribs of a wing at local level against brazier load. This study has been taken place while converting metal wing in to composite wing. The objective of this study is to reduce the weight penalty to the maximum possible extent by removing material wherever feasible. This paper is limited to discuss about the linear buckling analysis of ribs against brazier load. The buckling factor of ribs under consideration are reported in terms of square root times the eigenvalue obtained from finite element analysis, which represent the nonlinear effect of bending moment on brazier load. This study has helped to reconfigure/redesign the interspar ribs of wing. This has led to substantial weight saving of 2.85 Kg which accpunts 15.77% reductions of total mass of inter spar ribs

Estimation of failure load of composite bonded joints using 1D and 2D FE analysis and the mathematical equation of strain and bond energy in the adhesive layer

Adhesively bonded composite (ABC) joints used in the composite structures are modeled using 1D and 2D elements to generate the finite-element mesh. The present modeling technique has captured the overall structural behavior of ABC joints precisely. The analytical study proposed a novel failure criterion of ABC joints after understanding the structural behavior of joints through the modeling approach. A failure criterion developed based on the principle of conservation of energy stored within the adhesive layer by virtue of its allowable strength properties and consumed by applying stress per a unit load. The ultimate failure load of joints of popular configurations is estimated based on the principle of conservation of energy. The 1D–2D finite-element modeling approach has revealed the presence of a new form of mechanical energy named as the Bond energy concealed within the adhesive layer. A new failure mechanism and their modes are explained through the novel failure criterion. The numerical value of Bond energy is calculated by using a peculiar mathematical relationship between the allowable shear strength property and the Young’s modulus of the adhesive layer. The ultimate failure load estimated by the novel failure criterion is compared with that of third-party experimental results and found fair agreement of 1–11% difference, which is acceptable with appreciation