scholarly journals Analysis and Optimization of Damping Properties of Constrained Layer Damping Structures with Multilayers

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongyun Wang ◽  
Heow Pueh Lee ◽  
Canyi Du
Keyword(s):  
Composite Structures ◽  
Optimization Design ◽  
Design Method ◽  
Elastic Base ◽  
Optimal Designs ◽  
Base Layer ◽  
Design Parameters ◽  
Constrained Layer Damping ◽  
Damping Properties ◽  
Damping Characteristics

Constrained layer damping (CLD) structures, which are one of the composite structures with a softer viscoelastic material (VEM) layer sandwiched between a elastic base layer and a relatively stiffer constraining layer, are widely used in engineering applications for reducing vibration and noise radiation. To accurately predict and effectively control vibration and properly and quickly determine the design parameters, optimal designs for the CLD structures are necessary. The optimal designs depend on thoroughly understanding the damping characteristics of the CLD structures. In addition, for some cases, CLD structures with multi-constrained VEM layers are needed to suppress vibration more effectively. In this paper, an effective modeling method to accurately describe the damping properties and a quick optimization design method using COMSOL were proposed for CLD structures with multilayers in detail. The effects of nondimensional thickness ratios of the VEM and constraining layer to the base layer on the damping properties of CLD structures were analyzed. For CLD structures with different configurations, different constraints were selected to obtain the maximized damping in the optimization design. The conclusions from this research provide an insight into the effects of thicknesses of VEM and constraining layers on the damping properties of CLD structures regardless of its size. The modeling and optimal methods using COMSOL in this paper are not limited to CLD structures and can be used by other structures also.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

The Biomimetic Shark Skin Optimization Design Method for Improving Lubrication Effect of Engineering Surface

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Yan Lu ◽  
Meng Hua ◽  
Zuomin Liu
Keyword(s):  
Coefficient Of Friction ◽  
Optimization Design ◽  
Design Method ◽  
Theory Model ◽  
Tribological Performance ◽  
Design Parameters ◽  
Width Ratio ◽  
Textured Surface ◽  
Shark Skin ◽  
Biomimetic Surface

Nature has long been an important source of inspiration for mankind to develop artificial ways to mimic the remarkable properties of biological systems. In this work, a new method was explored to fabricate a biomimetic engineering surface comprising both the shark-skin, the shark body denticle, and rib morphology. It can help reduce water resistance and the friction contact area as well as accommodate lubricant. The lubrication theory model was established to predict the effect of geometric parameters of a biomimetic surface on tribological performance. The model has been proved to be feasible to predict tribological performance by the experimental results. The model was then used to investigate the effect of the grid textured surface on frictional performance of different geometries. The investigation was aimed at providing a rule for deriving the design parameters of a biomimetic surface with good lubrication characteristics. Results suggest that: (i) the increase in depression width ratio Λ decreases its corresponding coefficient of friction, and (ii) the small coefficient of friction is achievable when Λ is beyond 0.45. Superposition of depth ratio Γ and angle's couple under the condition of Λ < 0.45 affects the value of friction coefficient. It shows the decrease in angle decreases with the increase in dimension depth Γ.

OPTIMIZATION DESIGN OF ALU FOAM-FILLED S-SHAPE SQUARE TUBE UNDER AXIAL DYNAMIC LOADING

2020 ◽  
Vol 40 (04) ◽  
Author(s):  
NGUYEN VAN SY ◽  
NGUYEN THANH TAM
Keyword(s):  
Energy Absorption ◽  
Optimization Design ◽  
Optimal Designs ◽  
Design Parameters ◽  
Aluminum Foams ◽  
Response Surface Models ◽  
Element Simulation ◽  
Crushing Force ◽  
Surface Models ◽  
Foam Filled

This paper presents finite element simulation of the crash behavior and the energy absorption characteristics of S-shape square tubes which were fully or partially filled with aluminum foams. Base on the numerical results, it is found that, the density, the length of the filled foam and the thickness of tube directly affect the specific energy absorption (SEA) and peak crushing force (PCF) of the S-shape tubes. In this paper, the multi-objective particle swarm optimization (MOPSO) algorithm is employed to seek for optimal designs for the partial foam-filled S-shape tubes (PFSTs) and the full foam-filled S-shape tubes (FFSTs) with various design parameters such as the density, the length of filled foam and the thickness of tube, where response surface models are established to formulation SEA and PCF. The optimization results showed the energy absorption capability per unit mass of the PFSTs is more powerful than that of the FFSTs while the PCF constrained under the same level.

scholarly journals Robust optimization design of structures based on the specular reflection algorithm

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983413
Author(s):  
Qisong Qi ◽  
Qing Dong ◽  
Yunsheng Xin
Keyword(s):  
Robust Design ◽  
Structural Design ◽  
Optimization Design ◽  
Design Method ◽  
Specular Reflection ◽  
Design Parameters ◽  
Theoretical Design ◽  
Recent Advancement ◽  
Robust Optimization Design ◽  
Robust Design Method

The nominal values of structural design parameters are usually calculated using a traditional deterministic optimization design method. However, owing to the failure of this type of method to consider potential variations in design parameters, the theoretical design results can be far from reality. To address this problem, the specular reflection algorithm, a recent advancement in intelligence optimization, is used in conjunction with a robust design method based on sensitivity. This method not only is able to fully consider the influence of parameter uncertainty on the design results but also has strong applicability. The effectiveness of the proposed method is verified by numerical examples, and the results show that the robust design method can significantly improve the reliability of the structure.

A Study of Optimization of Blade Section Shape for a Steam Turbine

2005 ◽  
Author(s):  
Kyung-Nam Chung ◽  
Yang-Ik Kim ◽  
Ju-Heon Sung ◽  
In-Ho Chung ◽  
Sang-Hoon Shin
Keyword(s):  
Turbine Blade ◽  
Optimization Design ◽  
Design Method ◽  
Turbine Blades ◽  
Design Parameters ◽  
Surface Model ◽  
Impulse Turbine ◽  
Object Function ◽  
Section Shape ◽  
Blade Section

In this study, an optimization design method is established for a rotor blade of a Curtis turbine. Bezier curve is generally used to define the profile of turbine blades. However, this curve is not proper to a supersonic impulse turbine. Section shape of a supersonic turbine blade is composed of straight lines and circular arcs. That is, it has several constraints to define the section shape. Thus, in this study, a blade design method is developed by using B-spline curve in which local control is possible. The turbine blade section has been changed by varying three design parameters of exit blade angle, stagger angle and maximum camber. Then flow analyses have been carried out for the sections. Lift-drag ratio of the blade section is used as the object function, and it is maximized in the optimization. Second-order response surface model is employed to express the object function as a function of design parameters. Central composite design method is used to reduce the number of design points. Then, an evolution strategy is employed to obtain the optimized section of the Curtis turbine blade.

Multiobjective Optimization Design of a Pump–Turbine Impeller Based on an Inverse Design Using a Combination Optimization Strategy

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Wei Yang ◽  
Ruofu Xiao
Keyword(s):  
Response Surface ◽  
Optimization Design ◽  
Design Method ◽  
Inverse Design ◽  
Design Parameters ◽  
Surface Model ◽  
Optimization Strategy ◽  
Pump Turbine ◽  
Combination Optimization ◽  
Final Design

This paper presents an automatic multiobjective hydrodynamic optimization strategy for pump–turbine impellers. In the strategy, the blade shape is parameterized based on the blade loading distribution using an inverse design method. An efficient response surface model relating the design parameters and the objective functions is obtained. Then, a multiobjective evolutionary algorithm is applied to the response surface functions to find a Pareto front for the final trade-off selection. The optimization strategy was used to redesign a scaled pump–turbine. Model tests were conducted to validate the final design and confirm the validity of the design strategy.

scholarly journals Construction design based on particle group optimization algorithm

2021 ◽  
Vol 30 (1) ◽  
pp. 1040-1053
Author(s):  
Ying Xia ◽  
Mohammad Asif Ikbal ◽  
Mohd Asif Shah
Keyword(s):  
Intelligent Agents ◽  
Optimization Design ◽  
Design Method ◽  
Target Function ◽  
Pso Algorithm ◽  
Design Parameters ◽  
Program Optimization ◽  
Cross Sectional ◽  
Multi Objective ◽  
Run Time

Abstract The machines exhibit an intelligence which is artificial intelligence (AI), and it is the design of intelligent agents. A system is represented by an intelligent agent who perceives its environment and the success rate is maximized by taking the action. The AI research is highly specialized and there are two subfields and each communication fails often. The popular AI approaches include the traditional symbolic AI and computational intelligence. In order to optimize the seismic design of the reinforced concrete pier structure, the particle swarm optimization (PSO) algorithm and the reaction spectrum analysis method are combined; they establish a regular bridge of the design variable with cross-sectional characteristics and reinforcement ratios, with the target function. The seismic optimization design framework of the pier is transformed into a multi-objective optimization problem. Calculations show that the method can quickly obtain the optimal design parameters that meet multi-objective requirements. The improved PSO main program and the calling push-over program run time are 4.32 and 1347.56 s, respectively; the push-over program running time is 99.68% of the run time of the total program. Optimization of the seismic performance of the rear bridge pier is significantly improved and is more in line with the design method; the design method proposed in this article is more practical.

Fuzzy Reliability Optimization Design Method of Flange Based on the Tightness of Bolted Flanged Connections

2010 ◽  
Vol 37-38 ◽  
pp. 501-504
Author(s):  
Zhen Guo Sun ◽  
Bo Qin Gu ◽  
Xing Lu Huang
Keyword(s):  
Probability Theory ◽  
Optimization Design ◽  
Design Method ◽  
Design Parameters ◽  
Reliability Optimization ◽  
Fuzzy Reliability ◽  
Leakage Model ◽  
Sealing Performance ◽  
Random Probability ◽  
Fuzzy Random

Based on the time-correlated leakage model and fuzzy random probability theory, a formula for calculating fuzzy random reliability of sealing performance of bolted flanged connections was derived. The optimization variables were defined according to the sensitivity analysis of design parameters on fuzzy reliability of sealing performance. A fuzzy reliability optimization design method of flange was investigated, in which both the tightness of bolted flanged connections and the strength of flange were taken into consideration. As an example, an integral welding necked pipe flange was designed according to the optimization design method proposed in this paper. The designed flange not only satisfies the requirements of flange strength and sealing reliability of connections, but also its weight is reduced by 16% compared with that prescribed in the standard.

A genetic algorithm-based optimization design on self-sensing active constrained layer damped rotating plates

2011 ◽  
Vol 22 (17) ◽  
pp. 2069-2078 ◽  
Author(s):  
Zhengchao Xie ◽  
Pak Kin Wong ◽  
Ian Ian Chong
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Optimization Design ◽  
Single Layer ◽  
Element Model ◽  
Complex Model ◽  
Design Parameters ◽  
Constrained Layer Damping ◽  
Active Constrained Layer ◽  
Rotating Plate

This article investigates the vibration of a rotating constrained layer damped plate system. Although, currently, most existing research utilizes rotating structures as modeled beams, this work, however, models rotating structures as plates with constrained layer damping. Through the models investigated, this article develops a single-layer plate finite element model for a rotating structure to improve in both accuracy and versatility. Concurrently, existing research shows that the damping of the active constrained layer can provide more damping than the damping of the passive constrained layer. Therefore, in this study, the constraining layer is made of piezoelectric material and, thus, will work as both the self-sensing sensor and the actuator. In addition, a proportional control strategy is implemented to effectively control the damping in the rotating plate. Furthermore, due to a large number of design variables in the complex model incorporating viscoelastic damping, this study examines the application of genetic algorithm (GA) in optimizing the first two resonance amplitudes of the driving point mobility at the center of the rotating plate. A GA is applied to simultaneously determine several design parameters that maximize an objective function. Compared with a typical gradient search approach, Quasi-Newton method, GA can be more efficient and effective in finding the optimum configuration with the highest objective function value in the numerical example.

Research on the Optimization Design of the Bridge Foundation Bored Piles

2014 ◽  
Vol 1030-1032 ◽  
pp. 851-854
Author(s):  
Yong Chun Cheng ◽  
Ji Zhong Zhao ◽  
Peng Zhang ◽  
Jing Lin Tao ◽  
Ya Feng Gong
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Design Parameters ◽  
Foundation Design ◽  
Pile Diameter ◽  
Bored Piles ◽  
Vertical Bearing ◽  
Bridge Foundation ◽  
Vertical Bearing Capacity ◽  
Pile Length

This paper improves the method of calculating the vertical bearing capacity of bored piles, and unifies calculation method of singe pile under horizontal force, as well adds and modifies the design parameters of the specification, finally utilizes actual example to make a unified test of the above methods. The results proved that, through the optimization of bridge foundation design method of bored piles, it can significantly reduce construction cost, and makes the pile length, pile diameter, and reinforcement more safe and reasonable. At the same time, it has great directive significance to the design and construction of the bridge.

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