Fixture Design Methodology for Sheet Metal Assembly Using Computer Simulations

Manufacturing ◽  
2003 ◽  
Author(s):  
Stefan Dahlstro¨m ◽  
Jaime A. Camelio
Keyword(s):  
Sheet Metal ◽  
Design Methodology ◽  
Computer Experiments ◽  
Design Guidelines ◽  
Fixture Design ◽  
Machining Processes ◽  
Element Analysis ◽  
Response Models ◽  
Early Evaluation ◽  
Sheet Metal Assembly

Sheet metal assembly is a common manufacturing process for several products such as automobiles and airplanes. Since all manufacturing processes are affected by variation, the key characteristics or critical dimensions may not be nominal. This paper presents a new fixture design methodology for early evaluation of sheet metal assemblies. Fixture design has been extensively studied for machining processes. Unfortunately, little investigation has been done for sheet metal assembly processes considering the effect of fixture layout on the assembly dimensional variation. The new fixture design methodology is based on classifying the assemblies into three categories depending on the stiffness of the assembly components: rigid-rigid, compliant-rigid and compliant-compliant assembly. Finite Element Analysis (FEA) and design of computer experiments have been used to derive response models for sheet metal assembly applications. The response models are used to analyze the final assembly sensitivity to fixture, part and tooling variation for different assembly configurations. Based on these results several design guidelines are proposed for fixture design on sheet metal assembly.

scholarly journals Impact of Fixture Design Sheet Metal Assembly Variation

2002 ◽  
Author(s):  
Jaime A. Camelio ◽  
S. Jack Hu ◽  
Dariusz J. Ceglarek
Keyword(s):  
Sheet Metal ◽  
Design Methodology ◽  
Design Procedure ◽  
Fixture Design ◽  
Element Analysis ◽  
Sheet Metal Parts ◽  
Nonlinear Programming Methods ◽  
The Impact ◽  
Sheet Metal Assembly

This paper presents a new fixture design methodology for sheet metal assembly processes. The proposed approach focuses on the impact of fixture position on the dimensional quality of sheet metal parts after assembly, considering part and tooling variation and assembly springback. The optimization algorithm combines finite element analysis and nonlinear programming methods to find the optimal fixture position such that the assembly variation is minimized. The optimal fixture design methodology enables to significantly reduce the assembly variation in the presence of part and tooling variation. A case study is presented to demonstrate the design procedure.

Variation Analysis and Robust Fixture Design of a Flexible Fixturing System for Sheet Metal Assembly

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Bing Li ◽  
Hongjian Yu ◽  
Xiaojun Yang ◽  
Ying Hu
Keyword(s):  
Sheet Metal ◽  
Screw Theory ◽  
Parallel Robots ◽  
Fixture Design ◽  
Element Analysis ◽  
Fixture Layout ◽  
Influence Coefficients ◽  
Conditional Extremum ◽  
Sheet Metal Assembly

Flexibility of assembly systems is crucial to maintaining the competitiveness in the rapidly changing market. In this paper, a novel flexible fixturing system for sheet metal part assembly is presented, which utilizes parallel robots as reconfigurable fixture elements. The method of influence coefficients, combined with finite element analysis and screw theory, is used to analyze the variations in sheet metal assembly. In the analysis of assembly variations, a total of six variations involved in prewelding, underwelding, and afterwelding process are intensively considered. Screw theory is employed to model the kinematic and constraint features corresponding to the fixturing schemes. A robust fixture layout design model is developed based on the Lagrangian conditional extremum method. A case study illustrates that the robust optimal methodology and an optimal fixture layout scheme with less sensitivity can be obtained.

Deformable Sheet Metal Fixturing: Principles, Algorithms, and Simulations

1996 ◽  
Vol 118 (3) ◽  
pp. 318-324 ◽  
Author(s):  
W. Cai ◽  
S. J. Hu ◽  
J. X. Yuan
Keyword(s):  
Sheet Metal ◽  
Rigid Bodies ◽  
Fixture Design ◽  
Total Deformation ◽  
Element Analysis ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Manufacturing Operations ◽  
Nonlinear Programming Methods ◽  
Simulation Package

Fixture design is an important consideration in all manufacturing operations. Central to this design is selecting and positioning the locating points. While substantial literature exists in this area, most of it is for prismatic or solid workpieces. This paper deals with sheet metal fixture design. An “N-2-1” locating principle has been proposed and verified to be valid for deformable sheet metal parts as compared to the widely accepted “3-2-1” principle for rigid bodies. Based on the “N-2-1” principle algorithms for optimal fixture design are presented using finite element analysis and nonlinear programming methods to find the best “N” locating points such that total deformation of the deformable sheet metal is minimized. A simulation package called OFixDesign is introduced and numerical examples are presented to validate the “N-2-1” principle and optimal sheet metal fixture design approach.

Identifying Variable Effects on the Dimensional Quality of Compliant Assembly, Using Computer Experiments

2002 ◽  
Author(s):  
Stefan Dahlstro¨m ◽  
S. Jack Hu ◽  
Rikard So¨derberg
Keyword(s):  
Sheet Metal ◽  
Computer Experiments ◽  
Tolerance Analysis ◽  
Response Model ◽  
Element Analysis ◽  
Design Of Computer Experiments ◽  
Compliant Assembly ◽  
Aesthetic Form ◽  
Input Variables

Compliant sheet metal assemblies are often used as support structures in automobiles, airplanes and appliances. These structures not only provide a metrology frame for other modules to be assembled, but also give the product its aesthetic form. For this reason, the dimension quality of the assemblies is a very important factor to control, in order to make sure that the product will function as planned and continuously keep the product cost low. The assembly is influenced by variations in the component parts and the assembly processes. Tolerance analysis, as conducted in most industries today, is normally based on the assumption of rigid parts and is thus not always valid for sheet metal assemblies, due to their compliance. This paper will present a method, based on finite element analysis (FEA) and design of computer experiments, of identifying the influence of input variables on the final geometry variation of the assembly. The influence and the interactions among the input variables are analyzed with a response model that has been constructed, using the simulation results. This response model could be used to identify the important variables that need to be controlled in assembly. An example application is included, in order to demonstrate the simulation model and response model construction. Analysis of the results from the simulations can facilitate the design of the assembly process, in order to control the dimensional quality of the product.

scholarly journals Impact of fixture design on sheet metal assembly variation

2004 ◽  
Vol 23 (3) ◽  
pp. 182-193 ◽  
Author(s):  
Jaime A. Camelio ◽  
S. Jack Hu ◽  
Dariusz Ceglarek
Keyword(s):  
Sheet Metal ◽  
Fixture Design ◽  
Sheet Metal Assembly

Design of Automotive Torsion Beam Suspension Using Lumped-Compliance Linkage Models

2006 ◽  
Author(s):  
Naesung Lyu ◽  
Jungkap Park ◽  
Hiroyuki Urabe ◽  
Hiroyuki Tokunaga ◽  
Kazuhiro Saitou
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Computer Experiments ◽  
Simulation Software ◽  
Nonlinear Finite Element ◽  
Lumped Mass ◽  
Element Analysis ◽  
Response Models ◽  
Torsion Beam ◽  
Multi Body

This paper presents a new method for efficiently and accurately modeling the elasto-kinematic behaviors of torsion beam suspension systems and of other similar classes of mechanical systems, and a design method utilizing the models. The torsion beam is represented as a linkage of lumped mass joined by nonlinear springs, bending and torsion, whose stiffness are identified via off-line computational experiments using nonlinear finite element simulations. A number of such computer experiments are conducted off-line for representative dimensions of torsion beams, and the results are stored in surrogate response models. During design iterations, these surrogate response models are utilized to automatically construct a lumped-compliance linkage model of a torsion beam and integrate it into a multi-body suspension system model that can be simulated using commercial software. Comparison with a nonlinear finite element analysis demonstrates much improved accuracy of the proposed model over commercial flexible multi-body simulation software, with comparable computational speed. Finally, an example is presented on the multi-objective optimization of the cross section of the torsion beam using the developed surrogate response models.

scholarly journals Development of Simulation Based p-Multipliers for Laterally Loaded Pile Groups in Granular Soil Using 3D Nonlinear Finite Element Model

2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Muhammad Bilal Adeel ◽  
Muhammad Asad Jan ◽  
Muhammad Aaqib ◽  
Duhee Park
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Design Guidelines ◽  
American Petroleum Institute ◽  
Winkler Foundation ◽  
Group Effect ◽  
Pile Groups ◽  
Element Analysis ◽  
Laterally Loaded Pile ◽  
Laterally Loaded

The behavior of laterally loaded pile groups is usually accessed by beam-on-nonlinear-Winkler-foundation (BNWF) approach employing various forms of empirically derived p-y curves and p-multipliers. Averaged p-multiplier for a particular pile group is termed as the group effect parameter. In practice, the p-y curve presented by the American Petroleum Institute (API) is most often utilized for piles in granular soils, although its shortcomings are recognized. In this study, we performed 3D finite element analysis to develop p-multipliers and group effect parameters for 3 × 3 to 5 × 5 vertically squared pile groups. The effect of the ratio of spacing to pile diameter (S/D), number of group piles, varying friction angle (φ), and pile fixity conditions on p-multipliers and group effect parameters are evaluated and quantified. Based on the simulation outcomes, a new functional form to calculate p-multipliers is proposed for pile groups. Extensive comparisons with the experimental measurements reveal that the calculated p-multipliers and group effect parameters are within the recorded range. Comparisons with two design guidelines which do not account for the pile fixity condition demonstrate that they overestimate the p-multipliers for fixed-head condition.

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

Optimization of Sheet Metal Process Parameters of a Shield Case Piece Using Computer Simulation

2006 ◽  
Vol 510-511 ◽  
pp. 330-333
Author(s):  
M.C. Curiel ◽  
Ho Sung Aum ◽  
Joaquín Lira-Olivares
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Physical Processes ◽  
Forming Process ◽  
Element Analysis ◽  
One Step ◽  
Range Of Values ◽  
Principal Strains

Numerical simulations based on Finite Element Analysis (FEA) are widely used to predict and evaluate the forming parameters before performing the physical processes. In the sheet metal industry, there are basically two types of FE programs: the inverse (one-step) programs and the incremental programs. In the present paper, the forming process of the shield case piece (LTA260W1-L05) was optimized by performing simulations with both types of software. The main analyzed parameter was the blankholding force while the rest of the parameters were kept constant. The criteria used to determine the optimum value was based on the Forming Limit Diagram (FLD), fracture and wrinkling of the material, thickness distribution, and the principal strains obtained. It was found that the holding force during the forming process deeply affects the results, and a range of values was established in which the process is assumed to give a good quality piece.

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