scholarly journals Fuzzy Finite Element Analysis for Static Responses of Plane Structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tuan Hung Nguyen ◽  
Huynh Xuan Le ◽  
Ha Phuong Do
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Regression Models ◽  
Polynomial Regression ◽  
Triangular Fuzzy Number ◽  
Surface Model ◽  
Element Analysis ◽  
Static Responses ◽  
Fuzzy Finite Element ◽  
Polynomial Regression Models

Abstract In this paper, a fuzzy finite element algorithm is investigated to determine static responses of plane structures. This algorithm concerns finite element method, fuzzy sets theory, and response surface method. Firstly, the notion of a standardized triangular fuzzy number is developed and utilized to replace original fuzzy numbers in the surrogate models. Then, the error estimations between the training and the test sets are performed to select the suitable response surface model amongst the regression models. Lastly, a good performance combination of complete and non-complete quadratic polynomial regression models is proposed to define the responses of structures. The merits of the proposed algorithm are illustrated via numerical examples.

Bond Strength Models for Adhesively Bonded Flip-Chip Interconnects

2012 ◽  
Author(s):  
K. Sinha ◽  
A. Dasgupta ◽  
J. Caers
Keyword(s):  
Finite Element ◽  
Bond Strength ◽  
Response Surface ◽  
Flip Chip ◽  
Response Surface Model ◽  
Surface Model ◽  
Interfacial Bond Strength ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Bonding Parameters

This paper investigates the role of gold-to-gold interfacial metallurgical bonding on the bond strength of adhesively bonded flip-chip interconnects in microelectronic assemblies. [44] dealt with experimental investigation of the effect of bonding parameters on Au-Au interfacial bond strength. One of the major conclusions in [44] was that interfacial creep deformation closely correlated with the measured evolution of bond strength over time. This study presents a viscoplastic finite element analysis to capture the physical creep mechanisms that drive the development of this strength, so that the effect of the system architecture and bonding parameters can be effectively quantified. Based on the studies in literature [42, 43], the strength is assumed to depend on the area of the contact “a-spots,” which are defined here as the area over which the interfaces come into intimate, atomistically flat contact. The most important inputs to the finite element model consist of (i) interfacial geometry (with special emphasis on the surface roughness topology); (ii) viscoplastic mechanical properties of gold; and (iii) bonding parameters (force, temperature and time). The viscoplastic constitutive properties for gold are obtained partly from experiments conducted in this study and partly from the existing literature. The model inputs are parametrically varied in a systematic way within the design space, to obtain the variability expected in the bond strength. The simulation results are captured in a response surface model that can predict bond strength for a given set of fabrication conditions. The response surface model thus serves as a prediction tool critical for optimizing the interconnect strength and the durability of adhesively bonded flip chip assemblies.

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%.

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.

Growth relationships of individual flowers during late stages of floral development of Rhododendron L. 'Prize' and 'Gloria'

1998 ◽  
Vol 76 (8) ◽  
pp. 1350-1358
Author(s):  
H Brent Pemberton ◽  
Harold F Wilkins ◽  
James S Hodges
Keyword(s):  
Regression Models ◽  
Polynomial Regression ◽  
Cold Treatment ◽  
Female Flower ◽  
Growth Patterns ◽  
Strongly Correlated ◽  
Floral Part ◽  
Growth Measurement ◽  
Hormonal Content ◽  
Polynomial Regression Models

Single terminal inflorescences from two-stemmed plants of Rhododendron L. cv. 'Prize' and 'Gloria' were recurrently sampled during a 9°C cold treatment and subsequent forcing period in an 18°C growth chamber until plants reached anthesis. At each sample period, bud length and width were measured on each inflorescence, while subtending bud scale, petal, stamen ('Gloria' only), style, peduncle and ovary length, ovary width, and flower weight were determined on the two most basally attached flowers within an inflorescence for each cultivar. Polynomial regression models were calculated for each floral growth measurement over time, except for bud length and width, for each of the four flowers within a cultivar. Comparison of regression models revealed differences in floral part growth patterns among the various flowers within each cultivar. During the first week of placement in 18°C forcing temperatures after the cold treatment, bud length was the only floral part to grow on 'Prize' plants, while only female flower parts grew on 'Gloria' plants. These results indicate differences in growth resumption patterns between cultivars after cold storage. However, petal and style length were strongly correlated to flower weight for both cultivars indicating that these measurements could be used in laboratory or field situations to determine the floral stage of growth. The growth equations described would be useful for controlling the variability among shoots and flowers for analytical determinations, such as hormonal content analysis, and for studying relationships of floral growth patterns to environmental stimuli that could be used to control flowering. The statistical techniques used in this research make it possible to reduce the number of plants for such studies, as measurements taken on different flowers on the same plant can be used for floral part growth comparisons despite the inherent correlation present between such measurements.Key words: morphology, dormancy, growth modeling, multivariate multiple regression, controlled environment.

scholarly journals Multiobjective Optimization of Precision Forging Process Parameters Based on Response Surface Method

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Fayuan Zhu ◽  
Zhaohui Wang ◽  
Mi Lv
Keyword(s):  
Finite Element ◽  
Service Life ◽  
Multiobjective Optimization ◽  
Response Surface ◽  
Process Parameters ◽  
Optimization Method ◽  
Surface Model ◽  
Forming Quality ◽  
Hollow Shaft ◽  
Precision Forging

In order to control the precision forging forming quality and improve the service life of die, a multiobjective optimization method for process parameters design was presented by applying Latin hypercube design method and response surface model approach. Meanwhile the deformation homogeneity and material damage of forging parts were proposed for evaluating the forming quality. The forming load of die was proposed for evaluating the service life of die. Then as a case of study, the radial precision forging for a hollow shaft with variable cross section and wall thickness was carried out. The 3D rigid-plastic finite element (FE) model of the hollow shaft radial precision forging was established. The multiobjective optimization forecast model was established by adopting finite element results and response surface methodology. Nondominated sorting genetic algorithm-II (NSGA-II) was adopted to obtain the Pareto-optimal solutions. A compromise solution was selected from the Pareto solutions by using the mapping method. In the finite element study on the forming quality of forging parts and the service life of dies by multiobjective optimization process parameters, the feasibility of the multiobjective optimization method presented by this work was verified.

Finite element analysis and optimization of spherical motion burnishing of low-alloy steel

2011 ◽  
Vol 226 (1) ◽  
pp. 161-176 ◽  
Author(s):  
J T Maximov ◽  
G V Duncheva
Keyword(s):  
Finite Element ◽  
Regression Models ◽  
Sliding Friction ◽  
Mechanical Tests ◽  
Problem Size ◽  
Element Analysis ◽  
Fem Model ◽  
Metallic Component ◽  
Tool Motion ◽  
Spherical Motion

A reliable finite element modelling (FEM) approach to the spherical motion burnishing (SMB) process is developed with a view to gaining a fundamental understanding of the process and its optimization. SMB is a patented method for mechanical surface treatment of external cylindrical faces aimed at the enhancement of the fatigue life of the metallic component as well as its roughness, micro-hardness, depth hardening, wear, and corrosion resistance. A special feature of SMB is its kinematics: the tool motion is a superposition of a spherical movement and a rectilinear translation with respect to the workpiece. In order to decrease the FEM problem size, an approximated kinematic theory for the SMB is developed. In accordance with this theory the tool motion is approximated with a series of planar movements. As a result, a plane strain SMB FEM model is developed. The initial roughness is modelled in order to to achieve a more realistic representation of the workpiece geometry. To establish the flow stress and sliding friction coefficient, a combined approach is developed which contains mechanical tests, sensitivity FEM analysis, and inverse FE analysis of the corresponding pushing process. A planned numerical experiment is carried out on the basis of the created SMB FEM model. Six regression models of the treated layer characteristics are obtained and analysed on the basis of the FEM simulations. The FEM results are evaluated and compared to the experimental ones and their validity is proved. Finally, the regression models are used as objective functions in a multi-objective optimization problem formulation of the SMB process. As a result, the optimal combination of the governing SMB parameters is established.

Practical fuzzy finite element analysis of structures

2001 ◽  
Vol 38 (2) ◽  
pp. 93-111 ◽  
Author(s):  
U.O. Akpan ◽  
T.S. Koko ◽  
I.R. Orisamolu ◽  
B.K. Gallant
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Fuzzy Finite Element
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