Tolerance Simulation of Compliant Sheet Metal Assemblies Using Automatic Node-Based Contact Detection

2008 ◽  
Author(s):  
Kristina Wa¨rmefjord ◽  
Lars Lindkvist ◽  
Rikard So¨derberg
Keyword(s):  
Simulated Data ◽  
Simulation Software ◽  
Contact Detection ◽  
Contact Modeling ◽  
Industrial Case Study ◽  
Critical Dimensions ◽  
Finite Element Software ◽  
Inspection Data ◽  
Variation Simulation

Tolerance simulation is a crucial tool for predicting the outcome in critical dimensions, and is used during early phases of product development in automotive industry. In order to increase the accuracy and the agreement with reality of the predictions even further, variation simulation software offer in some cases the possibility to perform compliant analysis, i.e. the parts are not restricted to be rigid. In compliant analysis contact modeling is an important feature. In this paper a simplified method for automatic contact detection, well suited for tolerance simulations, is suggested. Traditionally, those kinds of non-rigid simulations are very time consuming, but by using this kind of simplified contact modeling in the Monte Carlo simulations, the simulation times can be kept down. The method is tested on an industrial case study. The analyses are done with and without contact modeling and those results are compared to real inspection data. The contact modeling turns out to be an important feature; the correlation between the results with contact modeling and inspection data is much stronger than the correlation for simulations without contact modeling. When using the new contact modeling algorithm the correspondence between simulated data and inspection data is very satisfying and the algorithm seems to be faster than traditional finite element software.

Non-Rigid Variation Simulation for Ready-to-Assemble Furniture

2019 ◽  
Author(s):  
Kristina Wärmefjord ◽  
Rikard Söderberg ◽  
Lars Lindkvist ◽  
Andreas Dagman
Keyword(s):  
Future Development ◽  
Automotive Industry ◽  
Assembly Process ◽  
Furniture Industry ◽  
Contact Modeling ◽  
Material Models ◽  
Simulation Procedure ◽  
Variation Simulation

Abstract Ready-To-Assemble (RTA) furniture is becoming increasingly popular due to attractive pricing compared to standard furniture. However, for this kind of furniture to be attractive to the customer, the assembly process must be smooth. If the assembly requirements are fulfilled or not is, for this kind of assembly, ruled by the tolerances on part level. In this paper, a methodology for variation simulation of RTA furniture is presented. By predicting the fulfillment of requirement on assembly level, reasonable tolerances on part level can iteratively be set, to guarantee a smooth assembly process. The methodology includes material models, flexibility and bending during assembly, contact modeling and modeling of fastener elements between parts. Variation simulation is commonly used in the automotive industry and a comparison of variation simulation methodologies between the two kinds of industries is conducted. A major difference between RTA furniture business and automotive industry is that no fixtures are used for RTA furniture. This must be reflected in the simulation procedure. Furthermore, the results from the variation simulation need to be evaluated, and the results are dependent on the context of the assembled product. Both the assemblability and esthetical requirements, like flush, gap, and parallelism, need to be evaluated. The methodology is illustrated on a case study and future development and research needed to adapt variation simulation to furniture industry are discussed.

Defect Free Casting by Using Simulation Software

2013 ◽  
Vol 313-314 ◽  
pp. 1130-1134 ◽  
Author(s):  
C.M. Choudhari ◽  
K.J. Padalkar ◽  
K.K. Dhumal ◽  
B.E. Narkhede ◽  
S.K. Mahajan
Keyword(s):  
Casting Process ◽  
Shrinkage Porosity ◽  
Simulation Software ◽  
Cast Aluminum ◽  
Industrial Case Study ◽  
Aluminum Castings ◽  
Mould Filling ◽  
Improved Performance ◽  
And Control

The use of Aluminum castings parts in the automotive industry has increased dramatically over the past few decades. The driving force for this increased use is vehicle weight reduction for improved performance. In many cases the mechanical properties of the cast aluminum parts are superior to those of the cast iron or wrought steel parts being used.This paper proposes the computer simulation of the sand casting of Aluminum Plate. It aims to study the behavior of fluid flow during mould filling and solidification and to optimize the process parameters, which help to predict and control casting defects such as gas porosity and shrinkage porosity. Here an attempt is being made to model and simulate the casting process using the AutoCAST software. The technological as well as practical aspects of using casting software are illustrated with an industrial case study.

Geometrical Inspection Point Reduction Based on Combined Cluster and Sensitivity Analysis

Manufacturing ◽  
2003 ◽  
Author(s):  
Johan S. Carlson ◽  
Rikard So¨derberg ◽  
Lars Lindkvist
Keyword(s):  
Cluster Analysis ◽  
Computer Simulations ◽  
Small Subset ◽  
Industrial Case Study ◽  
Point Reduction ◽  
Minimum Number ◽  
Product And Process ◽  
Assurance Process ◽  
Inspection Data

Analyzing inspection data is an important activity in the geometry assurance process, which provides vital information about product and process performance. Since inspection is related to a significant cost, it is desirable with an intelligent inspection preparation where the motive is to gather as much information as possible about the product and the process with a minimum number of inspection points. In many situations, a large number of inspection points are used despite the fact that only a small subset of points is needed. The reason for this redundancy is that most systems have only a few principal causes affecting groups of variables. In this paper, we use methods of cluster analysis to find these natural groupings of inspection points and to select one representing point from each cluster. Furthermore, if the relationship between some of the process parameters and inspection points are known from experiments or from computer simulations, then the cluster analysis is combined with sensitivity-based reduction. In this way, an efficient reduced inspection plan is built up. The practical relevance of the proposed methodology for reduction is verified on an industrial case study and by computer simulations.

Including Assembly Fixture Repeatability in Rigid and Non-Rigid Variation Simulation

2010 ◽  
Author(s):  
Kristina Wa¨rmefjord ◽  
Rikard So¨derberg ◽  
Johan S. Carlson
Keyword(s):  
Simulation Model ◽  
Inspection Data ◽  
Variation Simulation ◽  
Assembly Fixture

The repeatability of the assembly fixtures influences the geometrical outcome of an assembly. To control the fixtures, capability studies are conducted. Those studies give however just information about the variability in a number of inspection points. In this paper, a method for transforming the variation in inspection data to variation in the contacts between workpiece and locators is described. By doing this, the fault localizing of the fixture is facilitated. Further, the accuracy of the variation simulations used to evaluate different concepts and designs can be improved. Usually, when data from a repeatability study are used as input to a variation simulation, the tolerances are only applied in the points that actually were inspected. The suggested methodology makes it possible to transform the tolerances containing the repeatability of the fixture to tolerances on the locating scheme, and they are thereby affecting every point in the simulation model, not only the inspected ones. The method is tested on a case study and the effect of including fixture repeatability in a variation simulation is investigated.

scholarly journals On systematically building a controlled natural language for functional requirements

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Alvaro Veizaga ◽  
Mauricio Alferez ◽  
Damiano Torre ◽  
Mehrdad Sabetzadeh ◽  
Lionel Briand
Keyword(s):  
Information System ◽  
Natural Language ◽  
Qualitative Methodology ◽  
Case Study Research ◽  
Empirical Evaluation ◽  
Functional Requirements ◽  
Industrial Case Study ◽  
Requirements Specifications ◽  
Financial Domain

AbstractNatural language (NL) is pervasive in software requirements specifications (SRSs). However, despite its popularity and widespread use, NL is highly prone to quality issues such as vagueness, ambiguity, and incompleteness. Controlled natural languages (CNLs) have been proposed as a way to prevent quality problems in requirements documents, while maintaining the flexibility to write and communicate requirements in an intuitive and universally understood manner. In collaboration with an industrial partner from the financial domain, we systematically develop and evaluate a CNL, named Rimay, intended at helping analysts write functional requirements. We rely on Grounded Theory for building Rimay and follow well-known guidelines for conducting and reporting industrial case study research. Our main contributions are: (1) a qualitative methodology to systematically define a CNL for functional requirements; this methodology is intended to be general for use across information-system domains, (2) a CNL grammar to represent functional requirements; this grammar is derived from our experience in the financial domain, but should be applicable, possibly with adaptations, to other information-system domains, and (3) an empirical evaluation of our CNL (Rimay) through an industrial case study. Our contributions draw on 15 representative SRSs, collectively containing 3215 NL requirements statements from the financial domain. Our evaluation shows that Rimay is expressive enough to capture, on average, 88% (405 out of 460) of the NL requirements statements in four previously unseen SRSs from the financial domain.

scholarly journals Investigation and Improvement of Standard External Lightning Protection System: Industrial Case Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4118
Author(s):  
I Made Yulistya Negara ◽  
Daniar Fahmi ◽  
Dimas Anton Asfani ◽  
IGN Satriyadi Hernanda ◽  
Rendi Bagus Pratama ◽  
...  
Keyword(s):  
Petrochemical Industry ◽  
Protection System ◽  
Lightning Protection ◽  
Industrial Case Study ◽  
Grounding System ◽  
Electromagnetic Transient ◽  
Petrochemical Company ◽  
Program Software ◽  
Ground Potential

In this study, the lightning protection system and grounding system of one plant of the petrochemical industry were investigated, evaluated, and improved. The methods used in this study were rolling sphere and angle protection methods. The grounding system of the building under study was modeled and simulated using ATP/EMTP (Alternative Transient Program/Electromagnetic Transient Program) software. The results show that the external lightning protection system of the prilling tower studied does not adhere to IEC 62305 and IEC 1024-1-1 standards. Moreover, the grounding configuration of the DCS building was not appropriate for protecting sensitive equipment inside. Lightning causes an enormous potential difference between lightning ground rods in the grounding system. Additionally, disabling the existing surge protective device (SPD) causes an increase in the magnitude of Ground Potential Rise at the DCS building. Improvement of the lightning protection system of the prilling tower and DCS building on Plant 1 of this petrochemical company as well as some other recommendations for improvements are proposed. This paper also shows evidence that external lightning protection, internal lightning protection, and the grounding system need to be connected to make an exemplary lightning protection system.

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