scholarly journals A Consistent Procedure Using Response Surface Methodology to Identify Stiffness Properties of Connections in Machine Tools

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1220 ◽  
Author(s):  
Jesus-Maria Hernandez-Vazquez ◽  
Iker Garitaonandia ◽  
María Fernandes ◽  
Jokin Muñoa ◽  
Luis Lacalle
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Machine Tools ◽  
Computational Cost ◽  
Fractional Factorial ◽  
Dynamic Responses ◽  
Design Stage ◽  
Design Parameters ◽  
Regression Equations ◽  
Design Variables

Accurate finite element models of mechanical systems are fundamental resources to perform structural analyses at the design stage. However, uncertainties in material properties, boundary conditions, or connections give rise to discrepancies between the real and predicted dynamic characteristics. Therefore, it is necessary to improve these models in order to achieve a better fit. This paper presents a systematic three-step procedure to update the finite element (FE) models of machine tools with numerous uncertainties in connections, which integrates statistical, numerical, and experimental techniques. The first step is the gradual application of fractional factorial designs, followed by an analysis of the variance to determine the significant variables that affect each dynamic response. Then, quadratic response surface meta-models, including only significant terms, which relate the design parameters to the modal responses are obtained. Finally, the values of the updated design variables are identified using the previous regression equations and experimental modal data. This work demonstrates that the integrated procedure gives rise to FE models whose dynamic responses closely agree with the experimental measurements, despite the large number of uncertainties, and at an acceptable computational cost.

Optimization Design of Pressure Shell in Underwater Vehicle Based on Response Surface Model

2009 ◽  
Vol 419-420 ◽  
pp. 89-92
Author(s):  
Zhuo Yi Yang ◽  
Yong Jie Pang ◽  
Zai Bai Qin
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Optimization Design ◽  
Engineering Application ◽  
Element Model ◽  
Response Surface Model ◽  
Design Stage ◽  
Surface Model ◽  
Design Variables ◽  
Structure Strength

Cylinder shell stiffened by rings is used commonly in submersibles, and structure strength should be verified in the initial design stage considering the thickness of the shell, the number of rings, the shape of ring section and so on. Based on the statistical techniques, a strategy for optimization design of pressure hull is proposed in this paper. Its central idea is that: firstly the design variables are chosen by referring criterion for structure strength, then the samples for analysis are created in the design space; secondly finite element models corresponding to the samples are built and analyzed; thirdly the approximations of these analysis are constructed using these samples and responses obtained by finite element model; finally optimization design result is obtained using response surface model. The result shows that this method that can improve the efficiency and achieve optimal intention has valuable reference information for engineering application.

Thermal Optimization of a Microchannel Heat Sink With Trapezoidal Cross Section

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Afzal Husain ◽  
Kwang-Yong Kim
Keyword(s):  
Shape Optimization ◽  
Thermal Resistance ◽  
Objective Function ◽  
Response Surface ◽  
Heat Sink ◽  
Fractional Factorial ◽  
Surface Model ◽  
Microchannel Heat Sink ◽  
Reference Shape ◽  
Design Variables

A microchannel heat sink shape optimization has been performed using response surface approximation. Three design variables related to microchannel width, depth, and fin width are selected for optimization, and thermal resistance has been taken as objective function. Design points are chosen through a three-level fractional factorial design of sampling methods. Navier–Stokes and energy equations for steady, incompressible, and laminar flow and conjugate heat transfer are solved at these design points using a finite volume solver. Solutions are carefully validated with the analytical and experimental results and the values of objective function are calculated at the specified design points. Using the numerically evaluated objective-function values, a polynomial response surface model is constructed and the optimum point is searched by sequential quadratic programming. The process of shape optimization greatly improves the thermal performance of the microchannel heat sink by decreasing thermal resistance of about 12% of the reference shape. Sensitivity of objective function to design variables has been studied to utilize the substrate material efficiently.

Mathematical Modelling of the Rear Drive Unit of a Lightweight Vehicle for Sensitivity Analysis of Vibration

2016 ◽  
Author(s):  
Jiewei Lin ◽  
Yi Qiu
Keyword(s):  
Mathematical Model ◽  
Adverse Effect ◽  
Sensitivity Analysis ◽  
Vertical Vibration ◽  
Fractional Factorial ◽  
Design Stage ◽  
Design Parameters ◽  
Mass Reduction ◽  
Drive Unit ◽  
Car Body

Lightweight technology is applied in the automobile industry because mass reduction is beneficial in improving fuel efficiency and reducing CO2 emissions. Apart from the car body and the power unit (the two heaviest parts of a vehicle), the driveline also has potential for a reduction in weight. The driveline transfers power to the wheels and plays an important role in the vehicle system. Vibration is induced by the road input and by unbalanced forces transmitted through the driveline to the car body. Mass reduction in the driveline could influence the dynamic behaviour of a vehicle but it is not yet clear how mass reduction affects vibration of the driveline, the vehicle ride and NVH performance — important considerations when designing a lightweight driveline. In the prototype design stage, a mathematical model provides a more flexible and less costly method of optimising the system dynamics. In this paper, a 14 degree-of-freedom mathematical model is developed to study the dynamics of a rear drive unit (RDU). The system consists of a rear differential gearbox, left and right constant velocity joints and driveshafts, a rear sub-frame, and bushings between the RDU and the sub-frame and between the sub-frame and the car body. Excitations from the rear wheels, rear suspensions, and input shaft were considered. The vertical acceleration at the rear sub-frame was calculated and correlated with a calibrated multi-body dynamic model of the vehicle developed in a parallel study. Using a fractional factorial design with the vehicle travelling on a smooth road at various speeds, a sensitivity analysis was carried out with the developed mathematical model to identify the contributions of the mass properties of the RDU and the bushing parameters to the vibration at the centre of gravity (COG) of the rear sub-frame. Results indicate that the effects of design parameters on the rear sub-frame vibration vary according to the vehicle speed. For vibration at the rear sub-frame, the most influential factors are the masses of the rear differential gearbox and the driveshaft, and the stiffness of the front right bushings between the RDU and the sub-frame. The stiffness of the front left bushing between the RDU and the sub-frame also has considerable effect on the subsystem response but only at higher speeds. Reducing the mass of the CV joint is beneficial in decreasing the vertical vibration at the COG of the rear sub-frame, while reductions in masses of the gearbox and the driveshafts tend to slightly increase the vertical vibration at the same location. However, the adverse effect brought by lightweight differential gearbox and driveshafts on vibration is relatively small that may be hardly detected by passengers. The adverse effect (if any) can be compromised by adjusting the stiffness of the front bushings between the gearbox and the sub-frame.

Design of composite helicopter rotor blades to meet given cross-sectional properties

2005 ◽  
Vol 109 (1100) ◽  
pp. 471-475 ◽  
Author(s):  
S. L. Lemanski ◽  
P. M. Weaver ◽  
G. F. J. Hill
Keyword(s):  
Finite Element ◽  
Objective Function ◽  
Helicopter Rotor ◽  
Design Parameters ◽  
Stochastic Methods ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design Variables ◽  
Non Linear ◽  
Optimisation Methods

Abstract This paper examines the design of a composite helicopter rotor blade to meet given cross-sectional properties. As with many real-world problems, the choice of objective and design variables can lead to a problem with a non-linear and/or non-convex objective function, which would require the use of stochastic optimisation methods to find an optimum. Since the objective function is evaluated from the results of a finite element analysis of the cross section, the computational expense of using stochastic methods would be prohibitive. It is shown that by choosing appropriate simplified design variables, the problem becomes convex with respect to those design variables. This allows deterministic optimisation methods to be used, which is considerably more computationally efficient than stochastic methods. It is also shown that the design variables can be chosen such that the response of each individual cross-sectional property can be closely modelled by a linear approximation, even though the response of a single objective function to many design parameters is non-linear. The design problem may therefore be reformulated into a number of simultaneous linear equations that are easily solved by matrix methods, thus allowing an optimum to be located with the minimum number of computationally expensive finite element analyses.

scholarly journals A study for the prediction of corona power on electrostatic precipitator based on simple and easy two-dimensional electrostatic simulation

2020 ◽  
Vol 9 (2) ◽  
pp. 586
Author(s):  
Chang-Hee Cho ◽  
Dong-Hoon Kim ◽  
Sang-Eon Park
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Response Surface ◽  
Electrostatic Precipitator ◽  
Three Dimensional ◽  
Element Model ◽  
Design Parameters ◽  
Two Dimensional ◽  
Stored Energy ◽  
Dimensional Finite Element

This study examines how the designing of an electrostatic precipitator can be carried out in a simple way. While it is of value to find out the theoretical values of design parameters using three-dimensional finite element model and numerical method, this study shows that employ-ing a two-dimensional finite element model and easily usable public-domain program is equally simple and fast. Variations of some physical properties occurring between an electrode and a duct are expressed using two design parameters. In this process, the design of the experi-ment and the response surface method are used based on the two-dimensional finite element model, as well as electrostatic simulation. A test using an electrostatic precipitator is performed and it is confirmed that a variation of corona power by the test is most similar with the varia-tion of stored energy by the simulation. A conversion factor that can predict corona power with the response surface function for the stored energy is proposed.  

Structural Optimization of a Machining Center Column Based on Response Surface Method

2012 ◽  
Vol 522 ◽  
pp. 663-667
Author(s):  
Ming Nan Sun ◽  
Guo Fu Yin ◽  
Teng Hu
Keyword(s):  
Finite Element ◽  
Structural Optimization ◽  
Response Surface ◽  
Response Surface Method ◽  
Surface Model ◽  
Element Analysis ◽  
Mean Frequency ◽  
Machining Center ◽  
Surface Method ◽  
Design Variables

In order to improve dynamic characteristics of a machining center column, this paper proposes a structural optimization method based on finite element method (FEM) and response surface method (RSM). In order to reduce number of design variables, the finite element analysis samples in design space are selected by using the central composite design (CCD) experiment method. On the basis of FEM results at these experiment samples, quadratic polynomials are employed to establish response surface model, which reflects the relationship between the response (mean frequency of the first four orders) and the design variables (the column structural sizes). The goal of getting maximum mean frequency is reached by using NLPQL algorithm in iSIGHT. Through the optimization, the mean frequency is increased by 8.12%.

scholarly journals Optimization of Pump Hydraulic Performance Based on the Response Surface Method

2018 ◽  
Author(s):  
Shengli Xu ◽  
Shaowei Zhong ◽  
Haixin Zhao
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Computational Cost ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Hydraulic Performance ◽  
Design Parameters ◽  
Meridional Plane ◽  
Hydraulic Efficiency ◽  
Surface Method

This paper studies the optimization method of pump hydraulic performance based on the response surface method. A parametric model of impeller and diffuser is established. Three-dimensional optimization is carried out on the basis of the initial model obtained by one-dimensional design method. We select the pump hydraulic efficiency and the head as objective function and constraint function. Response surface models are constructed to analyze the relationship between the objectives and the design variables, and the global optimization of hydraulic performance is realized. According to the internal flow characteristics of pump, this paper proposes the strategy of two steps optimization, which aims at meridional plane and blade shape, respectively, to solve the problem of large numbers of design parameters and computational cost. The optimization results show that the hydraulic efficiency of pump increased by 3.7%, and the head is nearly the same.

Damping Machine Tools With Imbedded Viscoelastic Materials Constrained by Shear Tubes

1995 ◽  
Author(s):  
Eric R. Marsh ◽  
Layton C. Hale
Keyword(s):  
Finite Element ◽  
Machine Tools ◽  
Design Parameters ◽  
Constrained Layer Damping ◽  
Structural Components ◽  
Viscoelastic Materials ◽  
The Common ◽  
Damping Treatments ◽  
The Relationship ◽  
Insight Into

Abstract This paper considers a passive damping method that can be applied to beam-like structures such as machine tool bases and columns. The method uses viscoelastic materials to dissipate energy in the manner of classic constrained-layer damping; however, the layers are embedded within the structure as opposed to being applied externally. This provides a robust means of incorporating damping without encountering several of the common disadvantages associated with external damping treatments. An analytical solution to the amount of damping that can be achieved using embedded layers is available, but is known to be inaccurate when the viscoelastic stiffness approaches that of the structural components. Therefore, a new prediction of the maximum damping level that can be expected in a structure is developed and presented here. This prediction gives good results in a wide variety of applications, and offers insight into the relationship between key design parameters. Finite element and experimental verification of the maximum damping predictor are also presented.

A New Approach for Predicting Residence Time Distribution of Subsurface Wastewater Infiltration System

2012 ◽  
Vol 518-523 ◽  
pp. 1720-1723
Author(s):  
Jin Feng Dong ◽  
Yue Zhang ◽  
Wei Yu Zhang
Keyword(s):  
Finite Element ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Design Stage ◽  
Design Parameters ◽  
Two Dimensional ◽  
Hydraulic Residence Time ◽  
New Approach ◽  
Finite Element Software

Hydraulic residence time (HRT) is one of the key design parameters controlling the removal efficiency of contaminants and nutrients in subsurface wastewater infiltration system (SWIS). A two-dimensional axisymetric finite element software called SEEP/W was used to simulate unsaturated and saturated flow within SWIS. The paper presents a methodology by example for estimating residence time distribution (RTD) at the design stage of SWIS.

A new modularization method of heavy-duty machine tool for green remanufacturing

2018 ◽  
Vol 232 (23) ◽  
pp. 4237-4254 ◽  
Author(s):  
Qiang Cheng ◽  
Yiliang Guo ◽  
Zhifeng Liu ◽  
Guojun Zhang ◽  
Peihua Gu
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Clustering Algorithm ◽  
Design Stage ◽  
Design Parameters ◽  
Advanced Manufacturing ◽  
Heavy Duty ◽  
Atomic Theory ◽  
Structure Domain ◽  
The Ideal

The green remanufacturing constitutes a type of recycling form that adapts to ecological and economic requirements and an important part of the advanced manufacturing technology. In order to improve the green remanufacturing capacity of heavy-duty machine tools, in this paper a heavy-duty machine tool module division method for green remanufacturing was proposed. The main lines were based on the four design domains of axiomatic design and innovatively extended to the remanufacturing domain. In the design stage, the process of remanufacturing was considered. The modular clustering algorithm based on atomic theory was employed, which was associated with the correlation and similarity between the design parameters in the structure domain and the remanufacturing domain, for the ideal modules of heavy-duty machine tools to be discovered. Finally, a heavy-duty gantry milling machine is used as an example to verify the validity of the proposed method.

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