Global behaviour of a composite stiffened panel in buckling. Part 1: Numerical modelling

Abstract

a b s t r a c tThe present study analyses an aircraft composite fuselage structure manufactured by the Liquid Resin Infusion (LRI) process and subjected to a compressive load. LRI is based on the moulding of high performance composite parts by infusing liquid resin on dry fibres instead of prepreg fabrics or Resin Transfer Moulding (RTM). Actual industrial projects face composite integrated structure issues as a number of structures (stiffeners, . . .) are more and more integrated onto the skins of aircraft fuselage. A representative panel of a composite fuselage to be tested in buckling is studied numerically. This paper studies which of the real behaviours of the integrated structures are to be observed during this test. Numerical models are studied at a global scale of the composite stiffened panel. Linear and non linear analyses are conducted. The Tsai-Wu criterion with a progressive failure analysis is implemented, to describe the global behaviour of the panel up to collapse. Also, three stiffener connection methods are compared at the intersection between two types of integrated structures. Load shortening curves permit to estimate the expected load and displacements.

Global behaviour of a composite stiffened panel in buckling. Part 2: Experimental investigation

“…This confirms the critical buckling load is correctly predicted by the numerical models [7], without introducing unit displacements -of the linear buckling eigenvalue -as a node displacement pre-load. …”

“…Final dimensions of the test panel are 870 mm in length and 509 mm in width [7]. Resin blocks are 60 mm high and 80 mm wide.…”

“…In the case of excellent bonding, severe stress concentrations may cause delaminations and fracture in the skin or in the stiffener flanges at these locations [1]. This paper is the experimental investigation of a previous work which was the numerical modelling of this panel [7]. It aims to show the particular behaviour of a panel manufactured by a resin infusion process [8].…”

“…Geometric imperfections of the skins are not considered since they have an almost negligible effect on the load at collapse [9]. The side stiffeners provide enough rigidity so that the panel borders do not buckle [7].…”

“…The critical buckling load F cr (corresponding to skin local buckling) has been recalculated by the linear buckling analysis [7] on the reference model. It equals 90.4 kN, which is close to the end of the linear behaviour in the non linear analysis, where F cr is approximately 90 kN.…”