ALEXANDER IVANOVICH OLEINIKOV Aircraft Engineering Faculty, Komsomolsk-on-Amur State Technical University Lenina prospect 27, 681013 Komsomolsk-on-Amur, Russian Federation [email protected] Keywords: forming, creep, age, transversely isotropic, kind of the stress state effect, wing panel, inverse problem, reverse engineering, computer-aided process design system. Abstract. Problems of inelastic straining of three-dimensional bodies with large displacements and turns are considered. In addition to the sought fields, surface forces and boundary displacements, original size and shape have also to be determined from specified residual displacements in these problems. Currently, forming of light metals poses tremendous challenges due to their low ductility at room temperature and their unusual deformation characteristics at hot-cold work: strong asymmetry between tensile and compressive behavior, and a very pronounced anisotropy. We proposed the constitutive models of steady-state creep of initially transverse isotropy structural materials the kind of the stress state has influence [1]. The forming process considered includes two stages: active stage of elastoviscoplastic straining of the blank in the die tooling and passive stage of unloading of the blank withdrawn from the die tooling. The final stress-strain state at the active stage is the initial state for the passive stage. Unloading is considered as purely elastic straining, with no increments of inelastic strains. The active stage, in turn, also includes two steps. At the first step, the frontal faces of the “cold” blank are pressed to the working surfaces of the die tooling, which results in elastoplastic straining of the blank. The second step includes the processes of stress relaxation and creep strain in the blank fixed in this die tooling during a given time at an elevated ageing temperature. Computer modeling of these forming processes involves the use of the finite element method for consecutive solutions of three-dimensional quasi-static problems of elastoplastic straining, relaxation, and unloading, and also determining boundary conditions from given residual displacements [2] . The paper gives basics of the developed computer-aided system of design, modeling, and electronic simulation targeting the processes of manufacture of wing integral panels. System application data resulting from computation of 3D-involute of a CAD-based panel model, determination of working surfaces of die tooling, three-dimensional analysis of stresses, and simulation of panel shaping under diverse thermo-mechanical and speed conditions are demonstrated. Modeling of forming of wing panels of the SSJ-100 aircraft are considered [2,3]. The modeling results can be used to calculate the die tooling, determine the panel processibility, and control panel rejection in the course of forming [3]. References [1] A.I. Oleinikov, Models for the steady-state creep of transversely isotropic materials with different tension and compression characteristics, J. Ind. Appl. Math. 5 (2011) 406-409. [2] B.D. Annin, A.I. Oleinikov and K.S. Bormotin, Modeling of forming of wing panels of the SSJ-100 aircraft, J. Appl. Mech. Physics 51 (2010) 579-589. [3] A.I. Oleinikov, A.I. Pekarsh, Integrated Design of Integral Panel Manufacture Processes. Dalnauka, Vladivostok, 2010.
Three-dimensional analytical model for effective elastic constants of transversely isotropic plates with multiple cracks: Application to stiffness reduction and steady-state cracking of composite laminates
