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To recognize different bearing fault patterns under different operating conditions, a novel multi-team competitive optimization (MTCO) algorithm is proposed. The algorithm is inspired by the competitive behaviors among multiple teams. In the structure, it consists of a three-level optimization organization structure, so that the more potential optimal areas can be searched. Meanwhile, some new strategies...
Flight Control System (FCS) is a key component in aircraft. The high reliability of FCS is needed to ensure the safety flight. In order to achieve the high reliability and make the overall mass and volume as small as possible, mission reliability of the multi-redundancy voting structure of FCS is used as the objective function. The types of the elements and the number of redundancies are chosen as...
In engineering design, to achieve high reliability and safety in multidisciplinary systems, Reliability Based Multidisciplinary Design Optimization (RBMDO) has received increasing attention. In this paper, Mean-value First Order Saddlepoint Approximation (MVFOSA) is introduced and combined with the collaborative optimization (CO) method to deal with the reliability analysis under aleatory uncertainty...
Ionic liquid (IL) based ultrasonic assisted extraction (ILUAE) was developed for the effective extraction of puerarin from Radix Puerariae Lobatae (RPL). The ILUAE parameters including the type of ILs, IL concentration, RPL amount, ultrasonic power and time were optimized by single-factor experiment and response surface methodology. Under the optimized experimental conditions, the best results were...
Many engineering systems are exposed to run in load-varying environment. Load has a significant impact on the deteriorating process of components and system. Distributing the loads optimally among components of a system can reduce the failure probability and prolong the system life. In this paper, an approach to load distribution for multi-state systems under selective maintenance strategy is developed...
In this paper, a unified uncertainty analysis method based on the extension universal generating function is proposed for engineering problems described by the mixture of random, interval and p-box variables. In the method, the univariate approximation approach is extended for mixed variables, and then the performance function is divided into three parts. Traditional universal generating function...
The bathtub-shaped curve is essential in interpreting the failure rate function for the reliability analysis, and its parameters determine the representation of the bathtub-shaped function. This paper introduces a parameterised bathtub curve that provides an adaptive bathtub-shaped failure rate function (ABF) modelling approach which can be also easily utilised as a universal objective for further...
Mechanical engineers always expect to design a structure which could work properly in its whole lifetime. But there exist many random factors, such as dimension, material property and applied forces. Hence structures based on determinate design could fail with high probability. Reliability-based Topology Optimization (RBTO) is a computer-automated design method which combines reliability analysis...
In this paper, we generalize a multi-state element (MSE) replacement optimization problem to multi-state systems (MSS), in which a global optimal MSE replacement policy is obtained to achieve better outcome than local optimal MSE replacement strategy which does not consider the system performance rate dependency. It can be also concluded from the illustrative case of a power station coal transportation...
There are a lot of uncertain factors in the gearbox transmission system of wind turbine. In this paper the controllable factors and uncontrollable factors in gearbox transmission system were analyzed; combining the optimization design theory and robust design theory the robust mathematical model of transmission system was established. In the model we take volume of gearbox as objective function and...
The relationships between quality characteristics and uncertain factors are unknown or complicated in most practical engineering optimal problems. To solve this problem a robust optimal model based on hybrid response face was proposed. The relationships between quality characteristics and uncertain factors were investigated; the hybrid response surface optimization strategy was set up to balance the...
Reliability allocation problems of large systems become easier if the optimization model can be decomposed and solved as a set of smaller, coordinated sub-problems. A hierarchical structure for optimal reliability allocation based on target cascading is proposed in this paper. An example is given to illustrative the method.
Many systems are required to perform a series of missions with finite breaks or limited maintenance resources between successive missions. In such cases, one of the most widely used maintenance policies is a selective maintenance in which a subset of feasible maintenance actions is chosen to satisfy the subsequent mission requirements. Traditional selective maintenance optimization problems reported...
Grid computing is a newly developed technology. Although the developmental tools and techniques for the grid have been extensively studied, the reliability of grid service can not satisfy the real-world application requirements. To resolve this problem, this paper introduces a fault recovery mechanism into grid nodes and gives a constraint on recovery amount. Moreover, a multi-objective optimization...
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