Reliability-based design optimization of monopile transition piece for offshore wind turbine system

Optimal design of heat exchangers using the progressive quadratic response surface model

The quality of an injection molded part is largely affected by the mold cooling. Consequently, this makes it necessary to optimize the mold cooling circuit when designing the part but prior to designing the mold. Various approaches of optimizing the mold cooling circuit have been proposed previously. In this work, optimization of the mold cooling circuit was automated by a commercial process integration and design optimization tool called Process Integration, Automation and Optimization (PIAnO), which is often used for large automotive parts such as bumpers and instrument panels. The cooling channels and baffle tubes were located on the offset profile equidistant from the part surface. The locations of the cooling channels and the baffle tubes were automatically generated and input into the mold cooling computer-aided engineering program, Autodesk Moldflow Insight 2010. The objective function was the deviation of the mold surface temperature from a given design temperature. Design variables in the optimization were the depths, distances and diameters of the cooling channels and the baffle tubes. For a more practical analysis, the pressure drop and temperature drop were considered the limited values. Optimization was performed using the progressive quadratic response surface method. The optimization resulted in a more uniform temperature distribution when compared to the initial design, and utilizing the proposed optimization method, a satisfactory solution could be made at a lower cost.

Design optimization of an injection mold for minimizing temperature deviation

Rubber isolators are mounted between a cooling module and a carrier to isolate the car body from vibration due to the rotation of the cooling fan. The isolators should be durable against fatigue loads originating from fan rotation and road disturbance. Thus, the design of rubber isolators is required to maximize both vibration isolation and fatigue life. In this study, the shapes of the rubber isolators are optimally designed using a process integration and design optimization (PIDO) tool that integrates the various computer-aided engineering (CAE) tools necessary for vibration and fatigue analyses, automates the analysis procedure and optimizes the design solution. In this study, we use CAE models correlated to the experimental results. A regression-based sequential approximate optimizer incorporating Process Integration, Automation and Optimization (PIAnO), a commercial PIDO tool, is employed to handle numerically noisy responses with respect to the variation in design variables. Using the analysis and design procedure established in this study, we successfully obtained the optimal shapes of the rubber isolators in two different cooling modules; these shapes clearly have better vibration isolation capability and fatigue lives than those of the baseline designs used in industry.

Shape optimization of rubber isolators in automotive cooling modules for the maximization of vibration isolation and fatigue life

This paper presents the procedure and results of the multi-objective design optimization of a seven-degrees-of-freedom (7DOF) robot manipulator for better global performance, which pertains to the Global Conditioning Index (GCI) and the Structural Length Index (SLI). The concepts of, and the calculation techniques for, GCI and SLI are introduced to allow their use as objective functions for optimization. The optimization techniques, which are Sequential Two-point Diagonal Quadratic Approximate Optimization (STDQAO), the Progressive Quadratic Response Surface Method (PQRSM), the micro genetic algorithm (μGA), and the evolutionary algorithm (EA), were explained briefly, and they are being used to optimize the global performance indices of the robot manipulator. Also, the results of the optimization and comparison of the four optimization methods are summarized in tables.

Comparative study of optimization technique for the global performance indices of the robot manipulator based on an approximate model

For effective construction of second-order response surface models, an efficient quad ratic approximation method is proposed in the context of trust region model management strategy. In the proposed method, although only the linear and quadratic terms are uniquely determined using 2n+1 design points, the two-factor interaction terms are mathematically updated by normalized quasi-Newton formula. In order to show the numerical performance of the proposed approximation method, a sequential approximate optimizer is developed and solves a typical unconstrained optimization problem having 2, 6, 10, 15, 30 and 50 design variables, a gear reducer system design problem and two dynamic response optimization problems with multiple objectives, five objectives for one and two objectives for the other. Finally, their optimization results are compared with those of the CCD or the 50% over-determined D-optimal design combined with the same trust region sequential approximate optimizer. These comparisons show that the proposed method gives more efficient than others.

Progressive Quadratic Approximation Method for Effective Constructing the Second-Order Response Surface Models in the Large Scaled System Design

A new interstage matching technique is presented for design of a wide-band multi-stage amplifier using commercial 60 nm GaN-on-silicon technology in the W-band. The proposed interstage matching network is designed as a two-pole conjugated impedance matching approach for wideband characteristics using low-characteristic impedance transmission lines and an optimized microstrip-coupled line. In particular, the microstrip-coupled line provides strong resonance at the desired frequency, enabling optimal conjugate impedance matching of both edge and intermediate frequencies simultaneously. The implemented W-band three-stage amplifier using the proposed interstage matching technique exhibited a small-signal gain above 14.1 dB from 75 to 103 GHz. Also, the output power between 92-100 GHz was greater than 25 dBm, and the maximum output power at 96 GHz was 25.8 dBm. The W-band amplifier was designed with an area of 2 mm $\times1.2$ mm.

https://ieeexplore.ieee.org/ielx7/6287639/6514899/09870800.pdf

Min-Su Kim

Papers

Progressive Quadratic Approximation Method for Effective Constructing the Second-Order Response Surface Models in the Large Scaled System Design

A W-Band Amplifier With a New Wide-Band Interstage Matching Technique Using Self-Resonance of a Microstrip-Coupled Line