Mehrdad Ahmadi Kamarposhti^1,*, Hassan Shokouhandeh², Ilhami Colak³, Kei Eguchi⁴

CMC-Computers, Materials & Continua, Vol.73, No.2, pp. 4139-4156, 2022, DOI:10.32604/cmc.2022.029011

Abstract One method for eliminating oscillations in power systems is using stabilizers. By applying an appropriate control signal in the excitation system of a generator, a power system stabilizer improves the dynamic stability of power systems. However, the issue that is of high importance is the correct design of these stabilizers. These stabilizers must be designed to have proper performance when operating conditions change. When designed incorrectly, not only they do not improve the stability margin, but also increase the oscillations. In this paper, the robust design of power system stabilizers on a four-machine power system has been performed. For this… More >

Manar B. AL-Hajji^1,*, Nabeel Abu Shaban², Shahnaz Al Khalil², Ayat Al-Jarrah³

Energy Engineering, Vol.118, No.5, pp. 1425-1438, 2021, DOI:10.32604/EE.2021.016413

Abstract Solar energy is regarded as one of the promising renewable energy sources in the world.The main aim of this study is to use the Taguchi-Grey relational grade analysis to optimize the performance of two Solar Air Heaters (SAHs). A typical Grey–Taguchi method was applied. The Orthogonal Array, Signal-to-Noise ratio, Grey Relational Grade, and Analysis of Variance were employed to investigate the performance characteristics of SAH. Experimental observations were made in agreement with Jordanian climate 32°00′ N latitude and 36°00′ E longitude with a solar intensity of 500 W\m². The operating factors selected for optimization are the tilt angle (T) with… More >

Xinqing Li¹, Qinghai Zhao^1,*, Hongxin Zhang¹, Tiezhu Zhang², Jianliang Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.2, pp. 683-704, 2021, DOI:10.32604/cmes.2021.015685

Abstract This paper presents a robust topology optimization design approach for multi-material functional graded structures under periodic constraint with load uncertainties. To characterize the random-field uncertainties with a reduced set of random variables, the Karhunen-Loève (K-L) expansion is adopted. The sparse grid numerical integration method is employed to transform the robust topology optimization into a weighted summation of series of deterministic topology optimization. Under dividing the design domain, the volume fraction of each preset gradient layer is extracted. Based on the ordered solid isotropic microstructure with penalization (Ordered-SIMP), a functionally graded multi-material interpolation model is formulated by individually optimizing each preset… More >

Shufang Song^*, Lu Wang, Yuhua Yan

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.1, pp. 383-399, 2020, DOI:10.32604/cmes.2020.09588

Abstract The robust design optimization (RDO) is an effective method to improve product performance with uncertainty factors. The robust optimal solution should be not only satisfied the probabilistic constraints but also less sensitive to the variation of design variables. There are some important issues in RDO, such as how to judge robustness, deal with multi-objective problem and black-box situation. In this paper, two criteria are proposed to judge the deterministic optimal solution whether satisfies robustness requirment. The robustness measure based on maximum entropy is proposed. Weighted sum method is improved to deal with the objective function, and the basic framework of… More >

Hasan Aftab Saeed¹, Satoshi Izumi¹, Shinsuke Sakai¹, Shigeyuki Haruyama², Masato Nagawa³, Hideki Noda³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.1, pp. 21-26, 2008, DOI:10.3970/icces.2008.005.021

Abstract This is the first attempt toward the development of robust design methodology applicable to gaskets as there is no such precedent in the sealing industry. This was achieved by drastically transforming the traditional approach toward the solution to leaking problem. This paper deals with a new all-metal gasket that incorporates strategically located circumferential annular lips that form seal lines with the flanges. The gasket, due to its special shape makes use of the material's spring effect, resulting in sealing performance. This approach is clearly distinct from the traditional one based on material development. By transforming a material development problem into… More >

Richard Degenhardt^{1, 2}

The International Conference on Computational & Experimental Engineering and Sciences, Vol.13, No.2, pp. 31-32, 2009, DOI:10.3970/icces.2009.013.031

Abstract This article has no abstract. More >

Zichun Yang^1,2, Maolin Peng^1,3,4, Yueyun Cao¹, Lei Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.4, pp. 409-442, 2014, DOI:10.3970/cmes.2014.098.409

Abstract A new multi-objective reliability-based robust design optimization (M ORBRDO) model is proposed which integrats the multi-objective robustness, the reliability sensitivity robustness and the six sigma robustness design idea. The pure-quadratic polynomial functions are adopted to fit the performance objective functions (POF) and the ultimate limited state functions (ULSF) of the structure. Based on the ULSF and the checking point method, the equations of the first order reliability index are calculated. The mapping transformation method is employed when the non-normal distribution variables are included. According to the POF and the Taylor series expansion method, the equations of mean value and standard… More >

Heng-Cheng Lin¹, Chieh Kung², Rong-Sheng Chen¹, Gin-Tiao Liang¹

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 55-64, 2006, DOI:10.3970/cmc.2006.003.055

Abstract Wafer level chip scale package (WLCSP) has been recognized providing clear advantages over traditional wire-bond package in relaxing the need of underfill while offering high density of I/O interconnects. Without the underfill, the solder joint reliability becomes more critical. Adding to the reliability concerns is the safety demand trend toward "green'' products on which unleaded material, e.g. lead-free solders, is required. The requirement of lead-free solders on the packages results in a higher reflow temperature profile in the package manufacturing process, in turn, complicating the reliability issue. This paper presents an optimization study, considering the fatigue reliability, for a wafer… More >