Stochastic Modeling and Analysis of a Heavy Duty Radiator

Author(s):  
V. Hariram ◽  
P. Robin Roy

Governmental agencies across the globe are constantly evolving with stringent emission laws to tackle the problem of CO2 and NOx/SOx emissions. New emission standards force the Truck OEM’s to redesign the engine. The paper is aimed to measure the header tube joint stress of the radiator subjected to random variations in geometry, shape and material properties. Linear analysis will not consider the uncertainty and randomness due to tolerance, process changes, part-part variation etc. Stochastic finite element analysis (FEA) is carried out to account the uncertainty in the system. The finite element model of radiator system is built and baseline linear simulation is performed to obtain the baseline deformation and baseline stress responses. Then the uncertainty and random variation due to the geometry, material and shape variable is defined by a normal distribution function. Random designs are generated by defining the upper and lower bound limit values for the input design variable. Random designs are populated using Monte-Carlo simulation technique. 250 random design points are created for each design variables. Then stochastic simulation is performed to evaluate the responses at random design points. Statistical and probabilistic tools are used to post process the simulation results. The paper showcases application of stochastic simulation method which aids in indentifying the robust design with minimum variations. This also enables engineers and designers to understand the relationship and significance between different design variables in designing energy efficient systems.

2013 ◽  
Vol 41 (1) ◽  
pp. 60-79 ◽  
Author(s):  
Wei Yintao ◽  
Luo Yiwen ◽  
Miao Yiming ◽  
Chai Delong ◽  
Feng Xijin

ABSTRACT: This article focuses on steel cord deformation and force investigation within heavy-duty radial tires. Typical bending deformation and tension force distributions of steel reinforcement within a truck bus radial (TBR) tire have been obtained, and they provide useful input for the local scale modeling of the steel cord. The three-dimensional carpet plots of the cord force distribution within a TBR tire are presented. The carcass-bending curvature is derived from the deformation of the carcass center line. A high-efficiency modeling approach for layered multistrand cord structures has been developed that uses cord design variables such as lay angle, lay length, and radius of the strand center line as input. Several types of steel cord have been modeled using the developed method as an example. The pure tension for two cords and the combined tension bending under various loading conditions relevant to tire deformation have been simulated by a finite element analysis (FEA). Good agreement has been found between experimental and FEA-determined tension force-displacement curves, and the characteristic structural and plastic deformation phases have been revealed by the FE simulation. Furthermore, some interesting local stress and deformation patterns under combined tension and bending are found that have not been previously reported. In addition, an experimental cord force measurement approach is included in this article.


Author(s):  
Rama Subba Reddy Gorla

Heat transfer from a nuclear fuel rod bumper support was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall heat transfer rates due to the thermodynamic random variables. These results can be used to identify quickly the most critical design variables in order to optimize the design and to make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in heat transfer and to the identification of both the most critical measurements and the parameters.


Author(s):  
Kevin O’Shea

Abstract The use of finite element analysis (FEA) in high frequency (20–40 kHz), high power ultrasonics to date has been limited. Of paramount importance to the performance of ultrasonic tooling (horns) is the accurate identification of pertinent modeshapes and frequencies. Ideally, the ultrasonic horn will vibrate in a purely axial mode with a uniform amplitude of vibration. However, spurious resonances can couple with this fundamental resonance and alter the axial vibration. This effect becomes more pronounced for ultrasonic tools with larger cross-sections. The current study examines a 4.5″ × 6″ cross-section titanium horn which is designed to resonate axially at 20 kHz. Modeshapes and frequencies from 17–23 kHz are examined experimentally and using finite element analysis. The effect of design variables — slot length, slot width, and number of slots — on modeshapes and frequency spacing is shown. An optimum configuration based on the finite element results is prescribed. The computed results are compared with actual prototype data. Excellent correlation between analytical and experimental data is found.


2019 ◽  
Vol 894 ◽  
pp. 60-71
Author(s):  
Minh Phung Dang ◽  
Thanh Phong Dao ◽  
Hieu Giang Le ◽  
Ngoc Thoai Tran

A Compliant XY micropositioning stage is purported for situating a material sample in nanoindentation tester process. This paper aims to develop, analyze and optimize a XY compliant micropositioning stage. The working stroke of proposed XY stage is amplified by combining the four-lever and a bridge amplification mechanism. To enhance the performances of the stage, the main geometric parameters are optimized by an integration method of Taguchi method, response surface method (RSM) and genetic algorithm (GA). Firstly, static analysis and dynamic analysis are conducted by the finite element analysis in order to predict initial performances of the XY stage. Secondly, the number of experiments and the data are retrieved by combination of the finite element analysis-integrated Taguchi method. Thirdly, the effects of main design variables on the output response sensitivity are considered. Later on, mathematical model for the amplification ratio was established by the RSM. Finally, based on the mathematical equation, the GA is adopted to define the optimal design variables. The results of numerical validations are in a good agreement with the predicted results. The results depicted that the proposed hybrid approach ensures a high reliability for engineering optimization problems.


2007 ◽  
Vol 345-346 ◽  
pp. 1581-1584
Author(s):  
Sang Woo Lee ◽  
Dae Young Shin ◽  
Kyoung Jin Chun

The safety valve has been designed to protect high pressure vessels. A fracture plate made of a circular thin plate is located within the safety valve. The circular thin plate has an outlet for fluid release and to help decrease the pressure. As such, fracture of the circular thin plate can occur at the appointed pressure. In this study, design variables of the safety valve were used to control fracture pressure so that it was easy to apply in the development of a new model of a safety valve. Design variables were fluid diameter of the safety valve, thickness of the fracture plate, filet radius of the clamping bolt, fracture pressure, and clamped torque of the clamping bolt. Design variables were selected, since the fracture experiment indicated that these variables might play a critical role in the fracture of the circular thin plate. Fracture pressure was calculated by the finite element analysis method and analyzed to affect the design variables on the fracture pressure. Using regression analysis, main design variables such as the fluid diameter, the thickness and the fillet were selected and the relationships of the variables were expressed by a regression equation. Furthermore, finite element analysis method and the regression equation were verified comparing with the experiment result.


2005 ◽  
Vol 109 (1100) ◽  
pp. 471-475 ◽  
Author(s):  
S. L. Lemanski ◽  
P. M. Weaver ◽  
G. F. J. Hill

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.


2007 ◽  
Vol 23 (1) ◽  
pp. 79-85 ◽  
Author(s):  
W. Gao

AbstractThis paper present a new method called the interval factor method for the finite element analysis of truss structures with interval parameters. Using the interval factor method, the structural parameters and loads can be considered as interval variables, and the structural stiffness matrix can then be divided into the product of two parts corresponding to its deterministic value and the interval factors. The computational expressions for lower and upper bounds, mean value and interval change ratio of structural placement and stress responses are derived from the static governing equations by means of the interval operations. The effect of the uncertainty of the structural parameters and loads on the structural static responses is demonstrated by truss structures.


2011 ◽  
Vol 52-54 ◽  
pp. 1358-1363 ◽  
Author(s):  
M.R.M. Akramin ◽  
A. Zulkifli ◽  
M. Mazwan Mahat

Probabilistic analysis aims at providing an assessment of cracked structures and taking relevant uncertainties into account in a rational quantitative manner. The main focus of this research work is on uncertainties aspect which relates with the nature of crack in materials. By using cracked structures modelling, finite element calculation, generation of adaptive mesh, sampling of cracked structure including uncertainties factors and probabilistic analysis using Monte Carlo method, the rigidity of cracked structures is estimated. Assessment of the accuracy in probabilistic structures is essential when limited amount of data is available. The hybrid finite element and probabilistic analysis represents the failure probability of the structures. The probability of failure caused by uncertainties relates to loads and material properties of the structure are estimated using Monte Carlo simulation technique. Numerical examples are presented to show probabilistic analysis based on Monte Carlo simulation provides accurate estimates of failure probability. The comparison shows that the combination between finite element analysis and probabilistic analysis provides a simple and realistic of quantify the failure probability.


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