摘要：In this work, sandwich beams are studied to reveal the underlying size effects of the periodic core cells for the first time within the framework of free vibration analysis of such an advanced lightweight structure. The energy equivalence method is formulated as a theoretical approach that takes into account the cell size effect. It is compared with the asymptotic homogenization method and direct finite element method systematically to show their consistence and applicability. The accuracy of free vibration responses predicted by the detailed finite element model is used as the standard of comparison. It is shown that the cell size is an important parameter characterizing the cellular core rigidities that influence vibration responses. The homogenization model agrees exactly with the asymptotic solution of the analytical expression of the beam model only whenever the cell size tends to be infinitely small.

摘要：Extensibility and attainability of topology optimization are discussed by investigating a variety of simultaneous topology opti-mization methods extended from the standard ***,the state of the art is highlighted through systematic classification of developed methods,such as simultaneous topology optimizations of microstructure and macrostructure,structure and supports,structure and design-dependent loads,structure and locations of involved ***,some recent results about simultaneous topology optimization of structure and applied loads are *** is shown that the simultaneous topology optimization is an integrated methodology that extends the concept of standard topology optimization in the sense of systematic *** presence of more than one kind of design variable of different nature makes the optimization problem complex but enlarges the design space to attain the optimization.

摘要：The purpose of this paper is to present an extended topology optimization method for the stiffeners layout design of aircraft assembled structures. Multi-fastener joint loads and manufacturing constraints are considered simultaneously. On one hand, the joint loads are calculated and constrained within a limited value to avoid the failure of fasteners. On the other hand, the manufacturing constraints of the material distribution in the machining directions of stiffeners are implemented by an improved piecewise interpolation based on a beveled cut-surface. It is proven that the objective function is strictly continuous and differentiable with respect to the piecewise interpolation. The effects of the extended method with two different constraints are highlighted by typical numerical examples. Compared with the standard topology optimization, the final designs have clearly shown the layout of stiffeners and the joint loads have been perfectly constrained to a satisfying level.

摘要：The squirrel-cage elastic support is one of the most important components of an aero-engine rotor system.A proper structural design will favor the static and dynamic performances of the *** view of the deficiency of the current shape optimization techniques,a new mapping approach is proposed to define shape design variables based on the parametric equations of 3D curves and *** is then applied for the slot shape optimization of a squirrel-cage elastic *** this end,an automatic design procedure that integrates the Genetic Algorithm (GA) is developed to solve the *** typical examples with different shape constraints are *** results provide reasonable optimum designs for the improvement of stiffness and strength of the squirrel-cage elastic support.