共查询到20条相似文献,搜索用时 15 毫秒
1.
Zhonglai Wang Gang Li Hong-Zhong Huang Xiao-Ling Zhang Yanfeng Li 《Journal of Mechanical Science and Technology》2012,26(7):2045-2049
Box-booms are widely used in some cranes. The strength of box-booms would continuously deteriorate with the use of time. In this paper, gamma process is employed to describe strength degradation when dealing with the overall stability of the box-boom. Furthermore, the total working time is not deterministic but random because of the random arrivals of tasks and the random working time of every task. By accounting for strength degradation and the random total working time, a time-dependent reliability-based design optimization (RBDO) model for the box-boom is proposed. An engineering case is used to illustrate the proposed model. 相似文献
2.
This paper presents a design methodology for determining configurations of slider air bearings considering the randomness
of the air-bearing surface (ABS) geometry by using the iSIGHT. A reliability-based design optimization (RBDO) problem is formulated
to minimize the variations in the mean values of the flying heights from a target value while satisfying the desired probabilistic
constraints keeping the pitch and roll angles within a suitable range. The reliability analysis is employed to estimate how
the fabrication tolerances of individual slider parameters affect the final flying attitude tolerances. The proposed approach
first solves the deterministic optimization problem. Then, beginning with this solution, the RBDO is continued with the reliability
constraints affected by the random variables. Reliability constraints overriding the constraints of the deterministic optimization
attempt to drive the design to a reliability solution with minimum increase in the objective. The simulation results of the
RBDO are listed in comparison with the values of the initial design and the results of the deterministic optimization, respectively.
To show the effectiveness of the proposed approach, the reliability analyses are simply carried out by using the mean value
first-order second-moment (MVFO) method. The Monte Carlo simulation of the RBDO’s results is also performed to estimate the
efficiency of the proposed approach. Those results are demonstrated to satisfy all the desired probabilistic constraints,
where the target reliability level for constraints is defined as 0.8. 相似文献
3.
4.
In the reliability designing procedure of the vehicle components, when the distribution styles of the random variables are unknown or non-normal distribution, the result evaluated contains great error or even is wrong if the reliability value R is larger than 1 by using the existent method, in which case the formula is necessary to be revised. This is obviously inconvenient for programming. Combining reliability-based optimization theory, robust designing method and reliability based sensitivity analysis, a new method for reliability robust designing is proposed. Therefore the influence level of the designing parameters’ changing to the reliability of vehicle components can be obtained. The reliability sensitivity with respect to design parameters is viewed as a sub-objective function in the multi-objective optimization problem satisfying reliability constraints. Given the first four moments of basic random variables, a fourth-moment technique and the proposed optimization procedure can obtain reliability-based robust design of automobile components with non-normal distribution parameters accurately and quickly. By using the proposed method, the distribution style of the random parameters is relaxed. Therefore it is much closer to the actual reliability problems. The numerical examples indicate the following: (1) The reliability value obtained by the robust method proposed increases (>0.04%) comparing to the value obtained by the ordinary optimization algorithm; (2) The absolute value of reliability-based sensitivity decreases (>0.01%), and the robustness of the products’ quality is improved accordingly. Utilizing the reliability-based optimization and robust design method in the reliability designing procedure reduces the manufacture cost and provides the theoretical basis for the reliability and robust design of the vehicle components. 相似文献
5.
《计算机集成制造系统》2015,(8)
为了提高多源不确定下多学科设计优化的效率,提出一种基于两级一体化策略的多学科可靠性设计优化方法。该方法采用一种单级概率可靠性设计优化与基于响应面的BLISS进行集成的策略,将传统嵌套循环的确定性多学科设计优化和多学科可靠性分析进行解耦、形成顺序执行的两个模块,减少了多学科可靠性分析次数和多学科分析调用频率,提高了多学科可靠性设计优化的效率。在多学科可靠性分析模块,采用一种序列化方法进行概率和非概率多学科可靠性分析。最后通过一个实例验证了方法的有效性。 相似文献
6.
Reliability-based topology optimization with uncertainties 总被引:2,自引:0,他引:2
Chwail Kim Semyung Wang Kyoung-ryun Rae Heegon Moon Kyung K. Choi 《Journal of Mechanical Science and Technology》2006,20(4):494-504
This research proposes a reliability-based topology optimization (RBTO) using the finite element method. RBTO is a topology
optimization based on probabilistic (or reliability) constraints. Young’s modulus, thickness, and loading are considered as
the uncertain variables and RBTO is applied to static and eigenvalue problems. The RBTO problems are formulated and a sensitivity
analysis is performed. In order to compute probability constraints, two methods—RIA and PMA— are used. Several examples show
the effectiveness of the proposed method by comparing the classical safety factor method. 相似文献
7.
Hong-Shuang Li 《Journal of Mechanical Science and Technology》2013,27(4):1021-1029
To reduce the computational effort of reliability-based design optimization (RBDO), the response surface method (RSM) has been widely used to evaluate reliability constraints. We propose an efficient methodology for solving RBDO problems based on an improved high order response surface method (HORSM) that takes advantage of an efficient sampling method, Hermite polynomials and uncertainty contribution concept to construct a high order response surface function with cross terms for reliability analysis. The sampling method generates supporting points from Gauss-Hermite quadrature points, which can be used to approximate response surface function without cross terms, to identify the highest order of each random variable and to determine the significant variables connected with point estimate method. The cross terms between two significant random variables are added to the response surface function to improve the approximation accuracy. Integrating the nested strategy, the improved HORSM is explored in solving RBDO problems. Additionally, a sampling based reliability sensitivity analysis method is employed to reduce the computational effort further when design variables are distributional parameters of input random variables. The proposed methodology is applied on two test problems to validate its accuracy and efficiency. The proposed methodology is more efficient than first order reliability method based RBDO and Monte Carlo simulation based RBDO, and enables the use of RBDO as a practical design tool. 相似文献
8.
9.
10.
In this study, an effective method for reliability-based design optimization (RBDO) is proposed enhancing sequential optimization and reliability assessment (SORA) method by convex approximations. In SORA, reliability estimation and deterministic optimization are performed sequentially. The sensitivity and function value of probabilistic constraint at the most probable point (MPP) are obtained in the reliability analysis loop. In this study, the convex approximations for probabilistic constraint are constructed by utilizing the sensitivity and function value of the probabilistic constraint at the MPP. Hence, the proposed method requires much less function evaluations of probabilistic constraints in the deterministic optimization than the original SORA method. The efficiency and accuracy of the proposed method were verified through numerical examples. 相似文献
11.
12.
13.
Yimin ZHANG 《Frontiers of Mechanical Engineering》2015,10(2):138
The reliability-based design optimization, the reliability sensitivity analysis and robust design method are employed to present a practical and effective approach for reliability-based robust design optimization of vehicle components. A procedure for reliability-based robust design optimization of vehicle components is proposed. Application of the method is illustrated by reliability-based robust design optimization of axle and spring. Numerical results have shown that the proposed method can be trusted to perform reliability-based robust design optimization of vehicle components. 相似文献
14.
Sangwon Hong Saeil Lee Sangook Jun Dong-Ho Lee Hyungmin Kang Young-Seok Kang Soo-Seok Yang 《Journal of Mechanical Science and Technology》2011,25(3):731-740
Reliability-based design optimization (RBDO) of the NASA stage 37 axial compressor is performed using an uncertainty model
for stall margin in order to guarantee stable operation of the compressor. The main characteristics of RBDO for the axial
compressor are summarized as follows: First, the values of mass flow rate and pressure ratio in stall margin calculation are
defined as statistical models with normal distribution for consideration of the uncertainty in stall margin. Second, Monte
Carlo Simulation is used in the RBDO process to calculate failure probability of stall margin accurately. Third, an approximation
model that is constructed by an artificial neural network is adopted to reduce the time cost of RBDO. The present method is
applied to the NASA stage 37 compressor to improve the reliability of stall margin with both maximized efficiency and minimized
weight. The RBDO result is compared with the deterministic optimization (DO) result which does not include an uncertainty
model. In the DO case, stall margin is slightly higher than the reference value of the required constraint, but the probability
of stall is 43%. This is unacceptable risk for an aircraft engine, which requires absolutely stable operation in flight. However,
stall margin obtained in RBDO is 2.7% higher than the reference value, and the probability of success increases to 95% with
the improved efficiency and weight. Therefore, RBDO of the axial compressor for aircraft engine can be a reliable design optimization
method through consideration of unexpected disturbance of the flow conditions. 相似文献
15.
16.
研究结构几何尺寸、结构材料体积及作用载荷不确定条件下的连续体结构可靠性拓扑优化问题,提出基于改进比例拓扑优化(Improved Proportional Topology Optimization,IPTO)算法的可靠性拓扑优化方法.基于概率方法描述变量的不确定性,建立综合考虑材料体积约束和可靠性约束且使柔度最小的连续体结构可靠性拓扑优化数学模型;为提高计算效率,使用基于解耦思想的混合法将可靠性拓扑优化问题解耦成可靠性分析和当量确定性拓扑优化两个独立子问题.在可靠性分析阶段,遵循一阶可靠度法中可靠性指标的几何意义,获取满足可靠性约束且服从正态分布的随机变量,并通过逆变换对其进行修正;在当量确定性拓扑优化阶段,以修正后的随机变量作为设计参数,使用具有无需获取灵敏度信息功能的IPTO算法对结构执行拓扑优化设计.最后使用MBB梁和悬臂梁两个算例证实了所提方法的有效性. 相似文献
17.
The reliability-based maintenance optimization model has been focused by the engineers and scholars but it has never been solved effectively to formulate the effect of a maintenance action on the optimization model.In existing works,the system reliability was assumed to be increased to 1 after a predictive maintenance.However,it is very difficult in the most practical systems.Therefore,a new reliability-based maintenance optimization model under imperfect predictive maintenance (PM) is proposed in this paper.In the model,the system reliability is only restored to Ri (0相似文献
18.
Yimin Zhang 《Frontiers of Mechanical Engineering in China》2008,3(4):369-376
The level of automobile design and manufacturing is an important sign of leadership in science and technology and economic
power. The achievements of theories and methods for reliability-based design of automobiles in China are reviewed. For reliability-based
design, the theories and practices, optimization, sensitivity, and robustness are estimated. The techniques of reliability-based
design for automobiles are developed. The techniques service to the “hollow” phenomena of kernel technology, product innovative
power, and independent development power can be solved. 相似文献
19.
Network topology has a critical effect on its reliability. Due to the complexity of networks, how to design a more reliable network topology is one of the fascinating and significant challenges. In this paper, inspired by the multi-scale model of biological systems which range from gene to individual cells, and up to the individual organism, we provide a novel method to design a reliable topology of large-scale networks. By means of fractal theory and its application in complex networks, a network topology can be described as consisting of the superposition of basic units, called fractal-cells, which are made up of several components and their connections. Based on this fractal-cell structure, we find that a fractal-cell network has structural similarity with its primitive structure, and then develop a method to build a reliable topology which is generated from a primitive ring structure. Numerical simulation compared with the existing methods and performing on real networks show that our proposed method is effective. 相似文献
20.
Jang Gyeong Uk Kim Chang-Wan Bae Daesung Cho Younghoon Lee Jeong-Jong Cho Seunghyeon 《Journal of Mechanical Science and Technology》2020,34(3):1249-1256
Journal of Mechanical Science and Technology - This study performed reliability-based robust design optimization (RBRDO) of stator and rotor shape of the IPM type electric motor to reduce the... 相似文献