Papers by Keyword: Topology Optimisation

Abstract: Designing structures with frequency constraints is an important task in aerospace engineering. Aerodynamic loading, gust loading, and engine vibrations all impart dynamic loads upon an airframe. To avoid structural resonance and excessive vibration, the natural frequencies of the structure must be shifted away from the frequency range of any dynamic loads. Care must also be taken to ensure that the modal frequencies of a structure do not coalesce, which can lead to dramatic structural failure. So far in industry, no aircraft lifting surfaces are designed from the ground up with frequency optimisation as the primary goal. This paper will explore computational methods for achieving this task.This paper will present a topology optimisation algorithm employing the Solid Isotropic Microstructure with Penalisation (SIMP) method for the design of an optimal aircraft wing structure for rejection of frequency excitation.

Abstract: The sub-frame of 2500HP fracturing truck is an important component, which connects to chassis with the vehicle equipment. Because the sub-frame bears tension, torsion and bending loads, enough rigidity and intensity are necessary for chassis. Based on the Pro/E software, the 3-D model of frame and sub-frame was constructed. Using topology optimization method, layout of the sub-frame was determined and location of crossbeams was arranged. Meanwhile, number and location of the connectors between main frame and sub-frame was analyzed, analysis result shows that carrying capacity of chassis can be enhanced without increasing connectors number of main frame and sub-frame. Some available reference can be provided for chassis manufacture

Abstract: The KNN method is extracted from the technique of pattern recognition for the continuum structure topology optimization design with information functional materials. Original design region is taken as initial sample space, and continuum structure's units are regarded as samples. Unit stress and displacement sensitivity are utilized as feature vector to describe sample, and the feature vectors' Euclidean distance is considered as the recognition standard to classify all the samples. One FEM package is utilized to process the entire optimization. Finally, the topology optimization result is obtained. Several examples are verified under different situations. The results indicate that the KNN method is feasible.

Abstract: Topology optimization is one of the most important methods of reducing the weight of structure. Optimality Criteria method (OC) as a heuristic way can be used to deal with this problem efficiently. Popular SIMP method implements micro-structural density as the design variable. During the process of optimization, numerical instabilities are always observed; Moreover, higher penalty factor is not better for decreasing intermediate density elements. In this paper a penalty factor is imposed in OC method, and a relation between the filtering area and elements is also obtained. Meanwhile, the nodal density is used as design variable for more smoothing boundary. The results show that numerical stability can be obtained, checkerboard patterns haven’t been observed, and the clear boundary of structure has been developed.

Abstract: By integrating cellular automaton (CA) theory into topology optimization of continuum, the local rule is defined for sensitivity analysis and updating of the design variable, according to the analysis of the structural mechanical response. Topology optimization design of loaded structure is conducted using minimal compliance as the optimization objective. The optimal distribution of material in the design domain is finally obtained. Comparing to other algorithms, the local rule has proved to be computationally efficient to solve structural topology optimization problems. The resulting optimal structures are free of numerical instabilities such as the checkerboard patterns and mesh dependency.

Abstract: Based on Solid Isotropic Microstructure with Penalization (SIMP) method, a mathematical model for topology optimization of EV is proposed, which has design objective as minimizing compliance, with volumetric and geometric constraints. To make results more engineering value, the BIW optimization of EV takes into account not only the static loads, but also the torsion load in turning and moment load in braking process of EV. A number of implementation aspects in solving the numerical instability problem generated in optimization process are discussed, including checkboard patterns and mesh-dependency. Topology optimization of EV body in white with geometry and volumetric constraints is conducted, showing effectiveness of the proposed model.

Abstract: For generating a more reasonable initial layout configuration, a three-dimensional topology optimization methodology of the steel-concrete composite structure is presented. Following Solid Isotropic Material with Penalization (SIMP) approach, an artificial material model with penalization for elastic constants is assumed and elemental density variables are used for describing the structural layout. The considered problem is thus formulated as to find the optimal material density distribution that minimizes the material volume under specified displacement constraints. By using the adjoint variable method for the sensitivity analysis, the optimization problem is efficiently solved by the gradient-based optimization algorithm. Numerical result shows that the proposed topology approach presented a novel structural topology of the simply-supported steel-concrete composite beam.

Abstract: This paper presents an integrated design technique to carry out simultaneous topology and sizing optimization of a two-dimensional truss structure. An optimization problem is set to find a structural layout and elements’ cross-sectional areas of a 2D truss such that objective functions including mass, compliance, and buckling factor are optimized. Design constraints consist of stress, buckling, and compliance. The concept of an adaptive ground elements approach and the encoding/decoding process are detailed. The multiobjective version of population-based incremental learning (PBIL) is employed to solve the design problem. The results reveal that the proposed design strategy is efficient and can be an effective engineering design tool.

Abstract: This paper proposes a meshless Galerkin level set method for structural shape and topology optimization of continua. To taking advantage of the implicit free boundary representation scheme, structural design boundary is represented through the introduction of a scalar level set function as its zero level set, to flexibly handle complex shape fidelity and topology changes by maintaining concise and smooth interface. Compactly supported radial basis functions (CSRBFs) are used to parameterize the level set function and also to construct the shape functions for mesh free function approximation. The meshless Galerkin global weak formulation is employed to implement the discretization of the state equations. This provides a pathway to simplify two numerical procedures involved in most conventional level set methods in propagating the discrete level set functions and in approximating the discrete equations, by unifying the two different stages at two sets of grids just in terms of one set of scattered nodes. The proposed level set method has the capability of describing the implicit moving boundaries without remeshing for discontinuities. The motion of the free boundary is just a question of advancing the discrete level set function by finding the design variables of the size optimization in time. One benchmark example is used to demonstrate the effectiveness of the proposed method. The numerical results showcase that this method has the ability to simplify numerical procedures and to avoid numerical difficulties happened in most conventional level set methods. It is straightforward to apply the present method to more advanced shape and topology optimization problems.

Abstract: This paper focuses on an approach to topology optimization and its engineering application. Based on SIMP (Solid Isotropic Microstructure with Penalization) method combined with Guide-Weight method, an approach to solve topology optimization problems is proposed. Then the topology optimization is applied in the design of a key connecting component in a sorghum harvester by the use of proposed method. The derivation process of the iteration formulations demonstrates that the proposed approach has the advantages of easiness to derive and good universality. The result is satisfactory and the convergence speed is fast enough for engineering application.