Dimension Error Analysis and Simulation of Sheet Metal Multistage Assemblies

2012 ◽  
Vol 201-202 ◽  
pp. 208-212
Author(s):  
De Zhong Yu ◽  
Xiang Hong Xu
Keyword(s):  
Error Analysis ◽  
Sheet Metal ◽  
Multistage Process ◽  
Transmitting Model

The dimension quality of sheet metal subassembly（SMS）, which is usually assembled in the multistage process, has serious effect on its performance. Based on the multistage transmitting model of dimension errors of SMS, this paper detailedly analyzed the dimension errors of SMS in locating phase, over-locating phase and springback phase, and also simulated their dimension errors by Matlab and FEM, and finally predicted the assembly dimension errors of aeroplane wainscot subassembly sample.

scholarly journals Analysis of Forming Limits in Sheet Metal Forming with Pattern Recognition Methods. Part 2: Unsupervised Methodology and Application

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1892 ◽  
Author(s):  
Christian Jaremenko ◽  
Emanuela Affronti ◽  
Andreas Maier ◽  
Marion Merklein
Keyword(s):  
Pattern Recognition ◽  
Sheet Metal ◽  
Optical Measurement ◽  
Unsupervised Classification ◽  
Evaluation Methods ◽  
Time Dependent ◽  
Measuring System ◽  
Forming Limit ◽  
Element Analysis

The forming limit curve (FLC) is used in finite element analysis (FEA) for the modeling of onset of sheet metal instability during forming. The FLC is usually evaluated by achieving forming measurements with optical measurement system during Nakajima tests. Current evaluation methods such as the standard method according to DIN EN ISO 12004-2 and time-dependent methods limit the evaluation range to a fraction of the available information and show weaknesses in the context of brittle materials that do not have a pronounced constriction phase. In order to meet these challenges, a supervised pattern recognition method was proposed, whose results depend on the quality of the expert annotations. In order to alleviate this dependence on experts, this study proposes an unsupervised classification approach that does not require expert annotations and allows a probabilistic evaluation of the onset of localized necking. For this purpose, the results of the Nakajima tests are examined with an optical measuring system and evaluated using an unsupervised classification method. In order to assess the quality of the results, a comparison is made with the time-dependent method proposed by Volk and Hora, as well as expert annotations, while validated with metallographic investigations. Two evaluation methods are presented, the deterministic FLC, which provides a lower and upper limit for the onset of necking, and a probabilistic FLC, which allows definition of failure quantiles. Both methods provide a necking range that shows good correlation with the expert opinion as well as the results of the time-dependent method and metallographic examinations.

Aspects of Searching some Possibilities to Diminish the Processing Errors at Stamping Process

2015 ◽  
Vol 809-810 ◽  
pp. 295-300
Author(s):  
Sergiu Constantin Olaru ◽  
Gheorghe Nagîţ ◽  
Marius Ionuţ Ripanu ◽  
Vasile Manole
Keyword(s):  
Sheet Metal ◽  
Quality Standards ◽  
Portable Device ◽  
Experimental Measurements ◽  
Processing Industry ◽  
Constructive Solution ◽  
Stamping Process ◽  
Metal Sheets ◽  
Processing Errors

Processing errors in the process of stamping, represent some of the most important aspect that requires attention when you want to process parts with a simple configuration. Reducing errors increase the quality of stamped parts, therefore the processing industry of blanks from metal sheets attaches great importance to them. Given the international quality standards it is required to study in detail the problem of eliminating these errors. As a result the results of researches on the establishment of a special portable device to eliminate the clearance between the sheet metal and the guidance rulers of the material in die in order to reduce the deformations of the sheet metal trough successive actions dies. Are presented the proposed constructive solution, its advantages and experimental measurements at stamping with the use of the proposed solution.

The Influnce of Some Parameters on the Quality of Deep Drawing of Cylindrical Cups without a Blank Holder

2015 ◽  
Vol 809-810 ◽  
pp. 259-264
Author(s):  
Dan Chiorescu ◽  
Gheorghe Nagîț ◽  
Oana Dodun
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Signal To Noise Ratio ◽  
Fractional Factorial ◽  
Major Influence ◽  
Forming Process ◽  
Sheet Metal Parts ◽  
Product Surface ◽  
Experimental Trials

Deep drawing is one of the most important processes for forming sheet metal parts. Besides its importance as a forming process, cup drawing also serves as a basic test for the sheet metal formability. This article investigates the influence of the die punch clearance, the average velocity in the active stage and the lubrication on the deep drawing quality expressed by the thickness evenness on the finished product surface. In order to minimize the number of experimental trials, a fractional factorial design was developed together with an orthogonal array, thus analyzing the contribution of the three parameters under study to the quality of the deep drawing process. Using TAGUCHI’s signal-to-noise ratio, we determine that ram velocity has a major influence, followed by the clearance between the active elements, while the contribution of lubrication is negligible. The results of the research are useful in developing a sensible design of experiments.

Study of the Parameters of Deep Drawing Process Based on the Simulation of Dynaform

2012 ◽  
Vol 249-250 ◽  
pp. 51-58
Author(s):  
Qing Wen Qu ◽  
Tian Ke Sun ◽  
Shao Qing Wang ◽  
Hong Juan Yu ◽  
Fang Li
Keyword(s):  
Friction Coefficient ◽  
Sheet Metal ◽  
Deep Drawing ◽  
Drawing Process ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Deep Drawing Process ◽  
Drawing Die ◽  
Drawing Speed

A simulation of deep drawing process on the sheet metal was done by using Dynaform, the influence of blank holder force, deep drawing speed and friction coefficient on the forming speed of sheet metal in the deep drawing process were got. The forming speed of sheet metal determines the quality of deep drawing, in the deep drawing process the blank holder force and the deep drawing speed are controllable parameters, the friction coefficient can be intervened and controlled, and it’s a manifestation of the interaction of all parameters, the main factors which influence the friction coefficient just have blank holder force, deep drawing speed and lubrication except the material. The conclusion of this study provides the basic data for the analysis of the lubrication of mould, the study of lubricant and the prediction of the service life of deep drawing die.

Simulation of the Wing-to-Fuselage Assembly Process

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Sergey Lupuleac ◽  
Nadezhda Zaitseva ◽  
Maria Stefanova ◽  
Sergey Berezin ◽  
Julia Shinder ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Contact Problem ◽  
Assembly Process ◽  
Multistage Process ◽  
Stochastic Nature ◽  
Closing The Gap ◽  
Compliant Parts ◽  
Level Parallelism ◽  
Task Level

The paper presents a simulation of the Airbus A350-900 wing-to-fuselage assembly process. The latter is a complex multistage process where the compliant parts are being joined by riveting. The current research analyzes the quality of the temporary fastener arrangement. The fastener arrangement is being checked to ensure that the residual gap between joined parts is small, and the fastener loads closing the gap are calculated. The deviations of the part shape from nominal are modeled via initial gaps. A cloud of initial gaps is generated based on the statistical analysis of the available measurements assuming the stochastic nature of local gap roughness. Through the reduction of the corresponding contact problem to a quadratic programming (QP) problem and the use of efficient QP algorithms together with the task-level parallelism, the mass contact problem solving on refined grids is accomplished.

Numerical Simulation of Forming Process for Cover with Stiffening Components Made of Grade 2 Titanium Sheet Metal

2016 ◽  
Vol 687 ◽  
pp. 206-211
Author(s):  
Wojciech Więckowski
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Empirical Studies ◽  
Strength Properties ◽  
Forming Process ◽  
Titanium Sheet ◽  
Plastic Properties ◽  
Fem Method

This study presents the findings of numerical simulations of forming process for an inspection hole cover with stiffening ribs made of thin grade 2 titanium sheet metal. The numerical simulation was carried out using the FEM method with PAMStamp 2G software. Numerical calculations were performed with consideration for the phenomenon of material strain hardening and anisotropy of plastic properties of the sheet metal formed. Properties of the grade 2 titanium alloy analysed in the simulations were adopted based on the results of the empirical studies. Adequate parameters of the forming process were selected in order to eliminate unfavourable phenomena of losing of material coherence and sheet metal wrinkling. The effect of conditions of friction between the sheet metal and tool and pressure force of the blank holder on the forming process was investigated. The analysis of the distribution of plastic strain and reduction in wall thickness of the drawn parts can be used for determination of the effect of changes in selected parameters and orientation of the specimen on the process of drawn part forming. The quality of drawn parts was assessed based on the shape inaccuracy determined during simulation of forming. The inaccuracy depended on the conditions of the process and strength properties of the titanium sheet metal.

A Contribution to the Optimisation of a Simple Shear Test

2009 ◽  
Vol 410-411 ◽  
pp. 467-472 ◽  
Author(s):  
Marion Merklein ◽  
M. Biasutti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Shear Test ◽  
The Finite Element Method ◽  
Simple Shear Test ◽  
Material Parameters

The finite element method is a widely used tool in sheet metal forming. The quality of the results of such an analysis depends largely on the applied constitutive model and its material parameters, which have to be determined experimentally. These data are relevant on the choice of the yield criterion among the wide range of options available in the commercial applications implementing the finite element method. Since the accuracy of material parameters estimation is therefore crucial, investigations were performed with an Al-Mg sheet alloy and a mild steel sheet to optimize a Miyauchi-based simple shear test. This method is one of the basic ways to investigate the plastic properties of a sheet metal up to large strains, which is very important for numerical analysis of sheet metal forming processes. Aim of the test is to determine the shear stress-strain correlation. In order to enhance the quality of the experimental results the detection of the deformation’s field, trough an optical measurement system, and the methodology for its evaluation are focus of the present study.

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