Variation Analysis of Accumulative Stresses in Multistep Assembly Processes Using Output Transformation Matrices

2017 ◽  
Author(s):  
Jia Lin ◽  
Sun Jin ◽  
Cheng Zheng ◽  
Fuyong Yang ◽  
Siyi Ding
Keyword(s):  
Computer Aided Design ◽  
Structural Reliability ◽  
Single Case ◽  
Fe Model ◽  
Assembly Process ◽  
Variation Analysis ◽  
Transformation Matrices ◽  
Compliant Assembly ◽  
Geometric Variation ◽  
Output Transformation

Geometric variation produces gaps or interferences between the mating features of parts when assembling them. To accomplish the operation, forces need to be applied to deform the parts; while as a price, stresses arise around the structure and accumulate as the assembly process proceeds, which could impair the structural reliability. A tool modeling and analyzing the accumulation of assembly stresses can help us predict and control it. Associated with geometric variation, the levels of assembly stresses are variables as well, thus variation analysis of them is required rather than a single case analysis; however, research on assembly variation analysis has focused mainly on the geometric variation itself. In a previous study, we developed a compliant assembly variation analysis method which is based on a Finite Element (FE) model condensation technique of substructuring (Lin J, et al. “Compliant assembly variation analysis of aeronautical panels using unified substructures with consideration of identical parts.” Computer-Aided Design, 2014.). In this paper, by introducing Output Transformation Matrices (OTMs) into the unified substructure system, we add the analysis of assembly stresses onto that of assembly deviations: no extra modeling work is needed, but the assembly stresses within a part are recovered from its assembly deviations by OTMs. Though these OTMs need to be generated in advance, this one-off effort will be relatively small when the assembly process to be analyzed involves multiple steps. A case study on an aeronautical panel assembly is presented to illustrate the proposed method and investigate the characteristics of assembly stresses.

Variation Analysis for Compliant Assembly

2000 ◽  
Author(s):  
S. Jack Hu ◽  
Yufeng Long ◽  
Jaime Camelio
Keyword(s):  
Sheet Metal ◽  
Assembly Line ◽  
Assembly Process ◽  
Variation Analysis ◽  
Assembly Lines ◽  
Compliant Assembly ◽  
Single Station ◽  
Dimensional Variation ◽  
Sheet Metal Assembly

Abstract Assembly processes for compliant non-rigid parts are widely used in manufacturing automobiles, furniture, and electronic appliances. One of the major issues in the sheet metal assembly process is to control the dimensional variation of assemblies throughout the assembly line. This paper provides an overview of the recent development in variation analysis for compliant assembly. First, the unique characteristics of compliant assemblies are discussed. Then, various approaches to variation modeling for compliant assemblies are presented for single station and multi-station assembly lines. Finally, examples are given to demonstrate the applications of compliant assembly variation models.

Compliant assembly variation analysis of sheet metal with shape errors based on primitive deformation patterns

2017 ◽  
Vol 232 (13) ◽  
pp. 2334-2351 ◽  
Author(s):  
Yunyong Li ◽  
Yong Zhao ◽  
Haidong Yu ◽  
Xinmin Lai
Keyword(s):  
Sheet Metal ◽  
Propagation Model ◽  
Surface Shape ◽  
Mode Analysis ◽  
Assembly Process ◽  
Variation Analysis ◽  
Compliant Assembly ◽  
Variation Propagation ◽  
Shape Errors ◽  
Deformation Patterns

In the compliant assembly of sheet metal, the performance of the product is highly related to the shape errors of surface. Therefore, variation analysis is generally required to reveal the influence principle of the components’ manufacturing variations on the surface shape errors of the product. The traditional compliant assembly variation analysis methods were used to build a variation propagation model based on characteristic points between parts and product without considering shape errors. In this paper, a new method based on primitive deformation patterns considering shape errors is proposed. The primitive deformation patterns of part can be obtained by natural mode analysis of ideal part, and the primitive deformation patterns of product can be calculated by the dynamic substructure method. The initial shape errors of part are decomposed into the individual contributions of primitive deformation patterns. Considering the force equilibrium relationship in assembly process, a variation propagation model is built based on the primitive deformation patterns between parts and product. This model reveals variation propagation in assembly process by the basic element of dimension error field (deformation patterns), which is convenient for evaluating the assembly quality. A case study on a panel parts assembly process is presented to demonstrate the proposed variation analysis method. The results show the effectiveness and accuracy of the proposed method compared with the method of finite element analysis conducted in commercial software ABAQUS.

scholarly journals Time-Dependent Reliability-Based Design Optimization Utilizing Nonintrusive Polynomial Chaos

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Yao Wang ◽  
Shengkui Zeng ◽  
Jianbin Guo
Keyword(s):  
Design Optimization ◽  
Structural Reliability ◽  
Polynomial Chaos ◽  
Time Dependent ◽  
Fe Model ◽  
Reliability Based Design Optimization ◽  
Wear Process ◽  
Reliability Based Design ◽  
Optimization Methodology ◽  
Wear Law

Time-dependent reliability-based design optimization (RBDO) has been acknowledged as an advance optimization methodology since it accounts for time-varying stochastic nature of systems. This paper proposes a time-dependent RBDO method considering both of the time-dependent kinematic reliability and the time-dependent structural reliability as constrains. Polynomial chaos combined with the moving least squares (PCMLS) is presented as a nonintrusive time-dependent surrogate model to conduct uncertainty quantification. Wear is considered to be a critical failure that deteriorates the kinematic reliability and the structural reliability through the changing kinematics. According to Archard’s wear law, a multidiscipline reliability model including the kinematics model and the structural finite element (FE) model is constructed to generate the stochastic processes of system responses. These disciplines are closely coupled and uncertainty impacts are cross-propagated to account for the correlationship between the wear process and loads. The new method is applied to an airborne retractable mechanism. The optimization goal is to minimize the mean and the variance of the total weight under both of the time-dependent and the time-independent reliability constraints.

Computational Fluid Dynamics Applied to River Boat Hull Optimization

2021 ◽  
Vol 55 (5) ◽  
pp. 94-108
Author(s):  
Harlysson W. S. Maia ◽  
Said Mounsif ◽  
Jassiel V. Hernández-Fontes ◽  
Rodolfo Silva
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computer Aided Design ◽  
Resistance Coefficient ◽  
Wave Profile ◽  
Total Resistance ◽  
Nsga Ii ◽  
Pressure Distributions ◽  
Aided Design ◽  
Geometric Variation

Abstract This paper extends the work of Maia and Said (“Analysis for Resistance Reduction of an Amazon School Boat through Hull Shape Modification Utilizing a CFD Tool,” 2019), proposing the optimization of a school boat hull using genetic algorithms and computational fluid dynamics (CDF) simulations. The study examines a school boat used for the transportation of children to schools in riverine communities of the Brazilian Amazon. The optimization was focused on reducing the hydrodynamic hull resistance by modifying the hull lines, using the NSGA-II (non-dominated sorting genetic algorithm II) algorithm in the CAD (computer aided design) CAESES environment. The objective of the study was to reduce the resistance coefficients: C wp (wave profile) and C wp trans (transverse wave profile), thus reducing the total resistance coefficient (C t) and the generated wave amplitude. Pressure distributions and flow lines were then evaluated to obtain an optimal modified hull with reduced wave emission (lower wave resistance) and, consequently, lower forward resistance. The proposed methodology resulted in a maximum reduction of 5% in the total resistance coefficient C t and in the identification of a trend of geometric variation of the hull for investigation in further studies.

Investigation of Thermal Influence on the Assembly of Polymer Electrolyte Membrane Fuel Cell Stacks

2012 ◽  
Vol 512-515 ◽  
pp. 1509-1514
Author(s):  
Lin Fa Peng ◽  
Dian Kai Qiu ◽  
Pei Yun Yi ◽  
Xin Min Lai
Keyword(s):  
Thermal Expansion ◽  
Fuel Cell ◽  
Contact Pressure ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Fe Model ◽  
Assembly Process

The assembly force in a proton exchange membrane fuel cell (PEMFC) stack affects the characteristics of the porosity and electrical conductivity. Generally, the stack is assembled at room temperature while it’s operated at about 80 °Cor even higher. As a result, the assembly pressure can’t keep constant due to thermal expansion. This paper focuses on the contact pressure between membrane electrode assembly (MEA) and bipolar plates in real operations. A three-dimensional finite element (FE) model for the assembly process is established with coupled thermal-mechanical effects. The discipline of contact pressure under thermal-mechanical effect is investigated. A single cell stack is fabricated in house for the analysis of contact pressures on gas diffusion layer at different temperatures. The results show that as the temperature increases, contact pressure increases due to thermal expansion. It indicates that the influence of thermal expansion due to temperature variation should be taken into consideration for the design of the stack assembly process.

Simulation and Optimization of Airframe Assembly Process

2018 ◽  
Author(s):  
Sergey Lupuleac ◽  
Nadezhda Zaitseva ◽  
Maria Stefanova ◽  
Sergey Berezin ◽  
Julia Shinder ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Statistical Analysis ◽  
Problem Solving ◽  
Contact Problem ◽  
Quality Measures ◽  
Assembly Process ◽  
Variation Analysis ◽  
Simulation And Optimization ◽  
The Mathematical Model ◽  
Variation Simulation

An approach for simulating the assembly process where compliant airframe parts are being joined by riveting is presented. The foundation of this approach is the mathematical model based on the reduction of the corresponding contact problem to a Quadratic Programming (QP) problem. The use of efficient QP algorithms enables mass contact problem solving on refined grids, which is needed for variation analysis and simulation as well as for the consequent assembly process optimization. To perform variation simulation, the initial gap between the parts is assumed to be stochastic and a cloud of such gaps is generated based on statistical analysis of the available measurements. The developed approach is illustrated with two examples, simulation of A350-900 wing-to-fuselage joining and optimization of A320 wing box assembly. New contact quality measures are discussed.

scholarly journals Assembly Variation Analysis of Aircraft Panels under Part-to-part Locating Scheme

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xia Liu ◽  
Luling An ◽  
Zhiguo Wang ◽  
Changbai Tan ◽  
Xiaoping Wang ◽  
...  
Keyword(s):  
Elastic Deformation ◽  
Assembly Process ◽  
Variation Analysis ◽  
Kinematic Theory ◽  
Statistical Variation ◽  
Variation Propagation ◽  
Fixed Part ◽  
Compliant Parts ◽  
Aircraft Panels

A typical aircraft panel is the assembly consisting of a multitude of thin and lightweight compliant parts. In panel assembly process, part-to-part locating scheme has been widely adopted in order to reduce fixtures. By this locating scheme, a part is located onto the pre-fixed part/subassembly by determinant assembly (DA) holes, and temporary fasteners (e.g., spring pin) are used for joining these DA hole-hole pairs. The temporary fasteners can fasten DA hole-hole pairs in the axial and radial directions of DA holes. The fastening in the radial directions is realized by the expansion of temporary fasteners. Although the usage of temporary fasteners helps reduce the positional differences between hole-hole pairs, their clamping forces thereby may lead to elastic deformation of compliant parts/subassemblies. Limited research has been conducted on such elastic deformation produced by temporary fastener and its influence on assembly dimensional quality. This paper proposes a novel rigid-compliant variation analysis method for aircraft panel assembly, incorporating the deformation in part-to-part locating process. Based on the kinematic theory and linear elasticity deformation assumption, the variation propagation through the locating process, as well as the entire assembly process of an aircraft panel, is formulated. Then, the statistical variation analysis is performed with Monte Carlo (MC) simulation. Finally, the proposed method is validated by a case study. The result shows the deformation in the part-to-part locating process significantly impacts the assembly variations, and our method can provide a more accurate and reliable prediction.

Compliant assembly analysis including initial deviations and geometric nonlinearity, part II: Plate structure

2018 ◽  
Vol 233 (11) ◽  
pp. 3717-3732 ◽  
Author(s):  
Tao Liu ◽  
Zhi-min Li ◽  
Sun Jin ◽  
Wei Chen
Keyword(s):  
Geometric Nonlinearity ◽  
Mindlin Plate ◽  
Variation Analysis ◽  
Governing Equations ◽  
Plate Structures ◽  
Orthotropic Composite ◽  
Compliant Assembly ◽  
Variation Propagation ◽  
Springback Prediction ◽  
Assembly Analysis

Part I of this paper (Liu et al., “Compliant assembly analysis including initial deviations and geometric nonlinearity, part I: Beam structure”) has studied the variation propagation of beam structures with consideration of initial deviations and geometric nonlinearity. In practices, plate structures are more commonly used in manufacturing fields, and the attempt of this paper is to expand previous methodology for the assembly process of orthotropic composite plate structures. Similarly, initial deviations and von Kármán-type geometric nonlinearity are introduced into variation analysis model, with Mindlin plate theory accounting for shear effect. The analyzed plates are set as orthotropic composite materials, which also preserve the compatibility with isotropic metal materials. Governing equations and corresponding finite element expressions can be obtained by applying the principle of virtual work. Also, a linearized model or noninitial model can be regarded as a degradation of origin governing equations. A variation analysis approach for plate structures is proposed to make more refined assembly variation predictions with consideration of initial deviations, fixture errors, and matching deviations. The verification of the developed method is implemented with case studies on springback prediction of two composite plates assembly.

Precision Assembly Process with Augmented Reality Technology Support

2013 ◽  
Vol 581 ◽  
pp. 106-111 ◽  
Author(s):  
Jozef Novak-Marcincin ◽  
Jozef Barna ◽  
Jozef Torok
Keyword(s):  
Augmented Reality ◽  
Computer Aided Design ◽  
Technology Support ◽  
Assembly Process ◽  
Assembly Structure ◽  
Motion Process ◽  
Exact Position ◽  
Augmented Reality Technology ◽  
Position And Orientation ◽  
Aided Design

This article presents possibilities of precision assembling process by using special tools of the augmented reality (AR) and logical procedures from related areas such as a Computer Aided Design and Planning. These possibilities are implemented in the virtual assembling environment of AR, where engineers and designers can see important information about an exact position and orientation of the single assembly element that creates a part of the entire assembly structure. By means of this the application of AR allows costumer to see the motion process of single assembly item according to its trajectory and prevents the possible mistakes in the assembling processes.

Sign in / Sign up

Export Citation Format

Share Document