Topology optimisation of a bulkhead component used in aircrafts using an evolutionary algorithm (original) (raw)
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Topology optimization of structures with stress constraints: Aeronautical applications
IOP Conference Series: Materials Science and Engineering, 2010
Structural optimization is a well known and frequently used discipline in aerospace applications since most of the optimization problems were stated in order to solve aeronautic structures. Since first works about structural topology optimization were published, different formulations have been proposed to obtain the most adequate design. Topology optimization of structures is the most recent branch of structural optimization. The first works about this topic were proposed by Bendsøe and Kikuchi in 1988 [1]. In this field of optimum design of structures, the aim is to obtain the optimal material distribution of a given amount of material in a predefined domain. The most usual formulation tries to maximize the stiffness of the structure by using a given amount of material. In this paper, we present a minimum weight formulation with stress constraints that avoids most of the drawbacks associated to maximum stiffness approaches. The proposed formulation is applied in the optimal design of aeronautical structures. Some examples have been studied in order to validate the formulation proposed.
IOP Conference Series: Materials Science and Engineering, 2020
Aircraft total weight plays a major role in aircraft design which results in additional payloads and better performance. There are many ways to reduce weight of aircraft structures, for example, using composite materials.Composite materials such as CFRP offer significant weight reduction for aircraft. Weight reduction improves fuel efficiency of the aircraft which results cost of savings. Besides using these light materials structural design optimization is currently a valid methodology which is applied in advanced engineering. Topology optimization is used to yield an optimized shape and material distribution for a set of loads and constraints within a given design space. Whereas this paper deals with topology optimization of fuselage ribs. By using this optimization technique, weight can be reduced 18.36 % of the original weight.
Proceedings of the International …, 2008
Structural optimization tools and computer simulations have gained the paramount importance in industrial applications as a result of innovative designs, reduced weight and cost effective products. Especially, in aircraft and automobile industries, topology optimization has become an integral part of the product design process. In this paper nonparametric topology optimization has been applied on a commercial aircraft vertical stabilizer component using ANSYS software. Suitable loads and constraints are applied on the initial design space of the component to accommodate for fin gust, rudder deflection, lateral gust, and other loads experienced by an aircraft during actual flight maneuvering. An integrated approach has also been developed to verify the structural performance and to overcome the problem of nonmanufacturable topology optimization results. Post machining distortions are also simulated by using element deactivation technique first by developing an initial residual stress field through Sequential Coupled Field analysis. CATIA is used to convert the optimized FE model into geometry based CAD model and then virtual machining is done. At the end topology assisted design model is compared with the actual part that is being manufactured for the aircraft. It is inferred that topology optimization results in a better and innovative product design with enhanced structural performance and stability.
Procedia Engineering, 2011
This paper deals with topology optimization of composite structure using Bi-directional Evolutional Structural Optimization (BESO) method. By redefining the criteria of the optimization evolution progress, the proposed method is able to extend current BESO method from isotropic material to anisotropic composite material. The initial modification of BESO method is to allow for inefficient Material Element String (MES) to be removed while efficient MES to be added in the thickness direction of a composite structure. This modification can reduce the chance of high stress concentration in a composite structure and also produce the geometry which is easy to fabricate using fabrication techniques currently available. The results of a cantilever composite laminate under uniform inplane pressure are presented, showing that the proposed method can produce shape and topology for composite structures with optimal structure stiffness.
An enhanced genetic algorithm for structural topology optimization
International Journal for Numerical Methods in Engineering - INT J NUMER METHOD ENG, 2006
Genetic algorithms (GAs) have become a popular optimization tool for many areas of research and topology optimization an effective design tool for obtaining efficient and lighter structures. In this paper, a versatile, robust and enhanced GA is proposed for structural topology optimization by using problem-specific knowledge. The original discrete black-and-white (0–1) problem is directly solved by using a bit-array representation method. To address the related pronounced connectivity issue effectively, the four-neighbourhood connectivity is used to suppress the occurrence of checkerboard patterns. A simpler version of the perimeter control approach is developed to obtain a well-posed problem and the total number of hinges of each individual is explicitly penalized to achieve a hinge-free design. To handle the problem of representation degeneracy effectively, a recessive gene technique is applied to viable topologies while unusable topologies are penalized in a hierarchical manner. An efficient FEM-based function evaluation method is developed to reduce the computational cost. A dynamic penalty method is presented for the GA to convert the constrained optimization problem into an unconstrained problem without the possible degeneracy. With all these enhancements and appropriate choice of the GA operators, the present GA can achieve significant improvements in evolving into near-optimum solutions and viable topologies with checkerboard free, mesh independent and hinge-free characteristics. Numerical results show that the present GA can be more efficient and robust than the conventional GAs in solving the structural topology optimization problems of minimum compliance design, minimum weight design and optimal compliant mechanisms design. It is suggested that the present enhanced GA using problem-specific knowledge can be a powerful global search tool for structural topology optimization. Copyright © 2005 John Wiley & Sons, Ltd.
A comparative study on stress and compliance based structural topology optimization
IOP Conference Series: Materials Science and Engineering, 2017
Most of structural topology optimization problems have been formulated and solved to either minimize compliance or weight of a structure under volume or stress constraints, respectively. Even if, a lot of researches are conducted on these two formulation techniques separately, there is no clear comparative study between the two approaches. This paper intends to compare these formulation techniques, so that an end user or designer can choose the best one based on the problems they have. Benchmark problems under the same boundary and loading conditions are defined, solved and results are compared based on these formulations. Simulation results shows that the two formulation techniques are dependent on the type of loading and boundary conditions defined. Maximum stress induced in the design domain is higher when the design domains are formulated using compliance based formulations. Optimal layouts from compliance minimization formulation has complex layout than stress based ones which may lead the manufacturing of the optimal layouts to be challenging. Optimal layouts from compliance based formulations are dependent on the material to be distributed. On the other hand, optimal layouts from stress based formulation are dependent on the type of material used to define the design domain. High computational time for stress based topology optimization is still a challenge because of the definition of stress constraints at element level. Results also shows that adjustment of convergence criterions can be an alternative solution to minimize the maximum stress developed in optimal layouts. Therefore, a designer or end user should choose a method of formulation based on the design domain defined and boundary conditions considered.
Comparison of evolutionary-based optimization algorithms for structural design optimization
In this paper, a comparison of evolutionary-based optimization techniques for structural design optimization problems is presented. Furthermore, a hybrid optimization technique based on differential evolution algorithm is introduced for structural design optimization problems. In order to evaluate the proposed optimization approach a welded beam design problem taken from the literature is solved. The proposed approach is applied to a welded beam design problem and the optimal design of a vehicle component to illustrate how the present approach can be applied for solving structural design optimization problems. A comparative study of six population-based optimization algorithms for optimal design of the structures is presented. The volume reduction of the vehicle component is 28.4% using the proposed hybrid approach. The results show that the proposed approach gives better solutions compared to genetic algorithm, particle swarm, immune algorithm, artificial bee colony algorithm and differential evolution algorithm that are representative of the state-of-the-art in the evolutionary optimization literature.
Applied Mechanics and Materials, 2014
In the field of topology optimization problems, the Evolutionary Structural Optimization (ESO) method is one of the most popular and easy to use. When dealing with problems of reasonable difficulty, the ESO method is able to give very good results in reduced times and with a limited request of computational resources. Generally, main applications of this method are addressed to the definition of the optimal topology of a component subjected to a single load condition.
A smooth evolutionary structural optimization procedure applied to plane stress problem
Engineering Structures, 2014
Topological optimization problems based on stress criteria are solved using two techniques in this paper. The first technique is the conventional Evolutionary Structural Optimization (ESO), which is known as hard kill, because the material is discretely removed; that is, the elements under low stress that are being inefficiently utilized have their constitutive matrix has suddenly reduced. The second technique, proposed in a previous paper, is a variant of the ESO procedure and is called Smooth ESO (SESO), which is based on the philosophy that if an element is not really necessary for the structure, its contribution to the structural stiffness will gradually diminish until it no longer influences the structure; its removal is thus performed smoothly. This procedure is known as ''soft-kill''; that is, not all of the elements removed from the structure using the ESO criterion are discarded. Thus, the elements returned to the structure must provide a good conditioning system that will be resolved in the next iteration, and they are considered important to the optimization process. To evaluate elasticity problems numerically, finite element analysis is applied, but instead of using conventional quadrilateral finite elements, a planestress triangular finite element was implemented with high-order modes for solving complex geometric problems. A number of typical examples demonstrate that the proposed approach is effective for solving problems of bi-dimensional elasticity.