Static Stress Redesign of Plates by Large Admissible Perturbations

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Bhineka M. Kristanto ◽  
Michael M. Bernitsas
Keyword(s):  
Finite Element Analysis ◽  
Plate Thickness ◽  
Forced Response ◽  
Static Stress ◽  
Perturbation Equation ◽  
Element Analysis ◽  
Shell Elements ◽  
Structure Changes ◽  
The Finite Element Analysis ◽  
Large Admissible Perturbations

The purpose of this paper is to develop further the large admissible perturbation (LEAP) methodology to solve the static stress redesign problem for shell elements. The static stress general perturbation equation, which expresses the unknown stresses of the objective structure in terms of the baseline structure stresses, is derived first. This equation depends on the redesign variables for each element or group of elements, namely, the plate thickness. LEAP enables the designer to redesign a structure to achieve specifications on modal properties, static displacements, forced response amplitudes, and static stresses. LEAP is implemented in code RESTRUCT, which postprocesses the finite element analysis FEA results of the baseline structure. Changes on the order of 100% in the above performance particulars and in redesign variables can be achieved without repetitive FEAs. Several numerical applications on a simple plate and an offshore tower are used to verify the effectiveness of the LEAP algorithm for stress redesign.

Static Stress Redesign of Plates by Large Admissible Perturbations

2005 ◽  
Author(s):  
Bhineka M. Kristanto ◽  
Michael M. Bernitsas
Keyword(s):  
Plate Thickness ◽  
Forced Response ◽  
Static Stress ◽  
Perturbation Equation ◽  
Shell Elements ◽  
Modal Properties ◽  
General Perturbation ◽  
Structure Changes ◽  
Admissible Perturbation ◽  
Large Admissible Perturbations

The LargE Admissible Perturbation (LEAP) methodology is developed further to solve static stress redesign problems for shell elements. The static stress general perturbation equation, which expresses the unknown stresses of the objective structure in terms of the baseline structure stresses, is derived first. This equation depends on the redesign variables for each element or group of elements; namely the plate thickness. LEAP enables the designer to redesign a structure to achieve specifications on modal properties, static displacements, forced response amplitudes, and static stresses. LEAP is implemented in code RESTRUCT which post-processes the FEA results of the baseline structure. Changes on the order of 100% in the above performance particulars and in redesign variables can be achieved without repetitive FEA’s. Several numerical applications on a simple plate and an offshore tower are used to verify the LEAP algorithm for stress redesign.

Static Stress Redesign of Structures by Large Admissible Perturbations

2003 ◽  
Vol 127 (2) ◽  
pp. 122-129 ◽  
Author(s):  
Michael M. Bernitsas ◽  
Bhineka M. Kristanto
Keyword(s):  
Cross Section ◽  
Forced Response ◽  
Static Stress ◽  
Neutral Axis ◽  
Perturbation Equation ◽  
Cross Sectional ◽  
Structure Changes ◽  
Large Admissible Perturbations ◽  
The Cross ◽  
Outer Fiber

The LargeE Admissible Perturbation (LEAP) methodology is developed further to solve static stress redesign problems. The static stress general perturbation equation, which expresses the unknown nodal stresses of the objective structure in terms of the baseline structure stresses, is derived first. This equation depends on the redesign variables for each element or group of elements; namely, the cross-sectional area and moment of inertia, and the distance between the neutral axis and the outer fiber of the cross section. This equation preserves the shape of the cross section in the redesign process. LEAP enables the designer to redesign a structure to achieve specifications on modal properties, static displacements, forced response amplitudes, and static stresses. LEAP is implemented in code RESTRUCT which post-processes the FEA results of the baseline structure. Changes on the order of 100% in the above performance particulars and in redesign variables can be achieved without repetitive finite element (FE) analyses. Several numerical applications on a simple cantilever beam and an offshore tower are used to verify the LEAP algorithm for stress redesign.

Static Stress Redesign of Structures by Large Admissible Perturbations

2003 ◽  
Author(s):  
Michael M. Bernitsas ◽  
Bhineka M. Kristanto
Keyword(s):  
Cross Section ◽  
Forced Response ◽  
Static Stress ◽  
Neutral Axis ◽  
Perturbation Equation ◽  
Cross Sectional ◽  
Structure Changes ◽  
Large Admissible Perturbations ◽  
The Cross ◽  
Outer Fiber

The LargE Admissible Perturbation (LEAP) methodology is developed further to solve static stress redesign problems. The static stress general perturbation equation, which expresses the unknown nodal stresses of the objective structure in terms of the baseline structure stresses, is derived first. This equation depends the on the redesign variables for each element or group of elements; namely, the cross-sectional area and moment of inertia, and the distance between the neutral axis and the outer fiber of the cross section. This equation preserves the shape of the cross-section in the redesign process. LEAP enables the designer to redesign a structure to achieve specifications on modal properties, static displacements, forced response amplitudes, and static stresses. LEAP is implemented in code RESTRUCT which post-processes the FEA results of the baseline structure. Changes on the order of 100% in the above performance particulars and in redesign variables can be achieved without repetitive FE analyses. Several numerical applications on a simple cantilever beam and an offshore tower are used to verify the LEAP algorithm for stress redesign.

Finite-Element Analysis and Optimization of a Web Frame of a Tanker with Isolated Ballast System

1974 ◽  
Vol 18 (02) ◽  
pp. 85-95
Author(s):  
D. Finifter
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optimality Criterion ◽  
Plate Thickness ◽  
Element Analysis ◽  
Optimization Program ◽  
The Finite Element Analysis ◽  
Fully Stressed Design ◽  
The Web ◽  
Stressed Design

Finite-element analysis was used in the design of an unconventional tanker web frame which satisfies certain requirements stipulated by an isolated ballast system. The weight of the web frame was then minimized using an optimality criterion based on a fully stressed design. A double iteration procedure was developed which allowed for the efficient use of the optimization program in conjunction with the finite-element analysis. The reduction in the weight of the web frame is dependent on the minimum allowed plate thickness as shown in the results of the paper.

Some Notes on the Finite Element Analysis of Tires

1995 ◽  
Vol 23 (3) ◽  
pp. 175-188 ◽  
Author(s):  
R. Gall ◽  
F. Tabaddor ◽  
D. Robbins ◽  
P. Majors ◽  
W. Sheperd ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Local Analysis ◽  
Element Analysis ◽  
Shell Elements ◽  
Development Cycle ◽  
The Finite Element Analysis ◽  
Modeling Techniques ◽  
Massively Parallel Processing ◽  
New Generation

Abstract Over the past ten years the Finite Element Analysis (FEA) has been increasingly integrated into the tire design process. The FEA has been used to study the general tire behavior, to perform parameter studies, and to do comparative analyses. To decrease the tire development cycle, the FEA is now being used as a replacement for certain tire tests. This requires the accuracy of the FEA results to be within those test limits. This paper investigates some of the known modeling techniques and their impact on accuracy. Some of the issues are the use of shell elements, assumptions for boundary conditions, and global/local analysis approaches. Finally, the use of new generation supercomputers, massively parallel processing systems (MPP), is discussed.

Tread Depth Effects on Tire Rolling Resistance

2001 ◽  
Vol 29 (3) ◽  
pp. 134-154 ◽  
Author(s):  
J. R. Luchini ◽  
M. M. Motil ◽  
W. V. Mars
Keyword(s):  
Finite Element Analysis ◽  
Common Knowledge ◽  
Rolling Resistance ◽  
Test Method ◽  
Tire Model ◽  
Element Analysis ◽  
Truck Tires ◽  
The Finite Element Analysis ◽  
Equilibrium Test ◽  
Depth Effects

Abstract This paper discusses the measurement and modeling of tire rolling resistance for a group of radial medium truck tires. The tires were subjected to tread depth modifications by “buffing” the tread surface. The experimental work used the equilibrium test method of SAE J-1269. The finite element analysis (FEA) tire model for tire rolling resistance has been previously presented. The results of the testing showed changes in rolling resistance as a function of tread depth that were inconsistent between tires. Several observations were also inconsistent with published information and common knowledge. Several mechanisms were proposed to explain the results. Additional experiments and models were used to evaluate the mechanisms. Mechanisms that were examined included tire age, surface texture, and tire shape. An explanation based on buffed tread radius, and the resulting changes in footprint stresses, is proposed that explains the observed experimental changes in rolling resistance with tread depth.

Interactive Graphics for the Analysis of Tires

1985 ◽  
Vol 13 (3) ◽  
pp. 127-146 ◽  
Author(s):  
R. Prabhakaran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Approximate Solutions ◽  
Interactive Graphics ◽  
Element Analysis ◽  
Analysis Process ◽  
Physical Problems ◽  
The Finite Element Analysis ◽  
Analysis Computer ◽  
Discretization Technique

Abstract The finite element method, which is a numerical discretization technique for obtaining approximate solutions to complex physical problems, is accepted in many industries as the primary tool for structural analysis. Computer graphics is an essential ingredient of the finite element analysis process. The use of interactive graphics techniques for analysis of tires is discussed in this presentation. The features and capabilities of the program used for pre- and post-processing for finite element analysis at GenCorp are included.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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