Optimal Design of Fixture Layout for Compliant Part With Application in Ship Curved Panel Assembly

Abstract In a ship assembly process, a large number of compliant parts are involved. The ratio of the part thickness to the length or the width is typically 0.001–0.012. Fixture design is a critical task in the ship assembly process due to its impact on the deformation and dimensional variation of the compliant parts. In current practice, fixtures are typically uniformly distributed under the part to be assembled, which is non-optimal, and large dimensional gaps may occur during assembly. This paper proposed a methodology for the optimal design of the fixture layout in the ship assembly process by systematically integrating direct stiffness method and simulated annealing algorithm, which aims to minimize dimensional gaps along the assembly interface to further improve the quality and efficiency of seam welding. The case study shows that the proposed method significantly reduced the dimensional gaps of the compliant curved panel parts in a ship assembly process.

Download Full-text

Fault Failure Diagnosis for Compliant Assembly Structures Using Statistical Modal Analysis

Manufacturing Science and Engineering, Parts A and B ◽

10.1115/msec2006-21086 ◽

2006 ◽

Author(s):

Prakash ◽

D. Ceglarek ◽

M. K. Tiwari

Keyword(s):

Modal Analysis ◽

Failure Diagnosis ◽

Industrial Case Study ◽

Mapping Procedure ◽

Compliant Part ◽

Compliant Assembly ◽

Dimensional Variation ◽

Compliant Parts ◽

Deformation Modes

This paper develops a new diagnostics methodology for N-2-1 fixtures used in assembly processes with compliant parts. The developed methodology includes: (i) the predetermined CAD-based dimensional variation fault patterns model; (ii) data-based dimensional variation fault model; and (iii) the fault mapping procedure isolating the unknown fault. The CAD-based variation fault pattern model is based on the piece-wise linear bi-partitioning of compliant part into deformed (faulty) and un-deformed regions. Data-based dimensional variation fault models are based on the statistical modal analysis (SMA) which allow to model part deformation with varying number of deformation modes. It is proved in the paper that these independent deformation modes are equivalent to the CAD-based faults models obtained in (i). The fault mapping procedure allows to diagnose the unknown fault by comparing the unknown fault variation pattern obtained from the SMA model with one of the predetermined CAD-based fault patterns. One industrial case study from an automotive roof framing assembly illustrates the proposed method.

Download Full-text

Fixture Layout Design of Sheet Metal Parts Based on Global Optimization Algorithms

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4037106 ◽

2017 ◽

Vol 139 (10) ◽

Cited By ~ 10

Author(s):

YanFeng Xing

Keyword(s):

Finite Element ◽

Global Optimization ◽

Sheet Metal ◽

Optimization Algorithms ◽

Layout Optimization ◽

Sheet Metal Parts ◽

Fixture Layout ◽

Fixture Layout Optimization ◽

Dimensional Variation

Fixture layout can affect deformation and dimensional variation of sheet metal assemblies. Conventionally, the assembly dimensions are simulated with a quantity of finite element (FE) analyses, and fixture layout optimization needs significant user intervention and unaffordable iterations of finite element analyses. This paper therefore proposes a fully automated and efficient method of fixture layout optimization based on the combination of 3dcs simulation (for dimensional analyses) and global optimization algorithms. In this paper, two global algorithms are proposed to optimize fixture locator points, which are social radiation algorithm (SRA) and GAOT, a genetic algorithm (GA) in optimization toolbox in matlab. The flowchart of fixture design includes the following steps: (1) The locating points, the key elements of a fixture layout, are selected from a much smaller candidate pool thanks to our proposed manufacturing constraints based filtering methods and thus the computational efficiency is greatly improved. (2) The two global optimization algorithms are edited to be used to optimize fixture schemes based on matlab. (3) Since matlab macrocommands of 3dcs have been developed to calculate assembly dimensions, the optimization process is fully automated. A case study of inner hood is applied to demonstrate the proposed method. The results show that the GAOT algorithm is more suitable than SRA for generating the optimal fixture layout with excellent efficiency for engineering applications.

Download Full-text

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

International Journal of Aerospace Engineering ◽

10.1155/2019/9563596 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 3

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.

Download Full-text

Multiobjective Optimization for Integrated Tolerance Allocation and Fixture Layout Design in Multistation Assembly

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2951951 ◽

2008 ◽

Vol 130 (4) ◽

Cited By ~ 13

Author(s):

Z. Li ◽

L. E. Izquierdo ◽

M. Kokkolaras ◽

S. J. Hu ◽

P. Y. Papalambros

Keyword(s):

Multiobjective Optimization ◽

Layout Design ◽

Tolerance Allocation ◽

Assembly Process ◽

Optimization Strategy ◽

Fixture Layout ◽

Dimensional Variation ◽

Product Variation ◽

Multistation Assembly

Cost and dimensional variation of products are significant attributes in multistation assembly processes. These attributes depend on product∕process tolerances and fixture layouts. Typically, tolerance allocation and fixture layout design are conducted separately without considering potential interrelations. In this work, we use multiobjective optimization for integrated tolerance allocation and fixture layout design to address interactions and to quantify tradeoffs among cost, product variation, and assembly process sensitivity. A nested optimization strategy is applied to a vehicle side frame assembly. Results demonstrate the presence and quantification of tradeoffs, based on which we introduce the concept of critical variation and critical budget requirements.

Download Full-text

Fixture Layout Design and Optimization of Sheet Metal Assembly Based on Genetic Algorithm for Optimization Toolbox

Volume 2: Advanced Manufacturing ◽

10.1115/imece2016-65413 ◽

2016 ◽

Author(s):

Yanfeng Xing ◽

Fang Wang ◽

Qing Ji

Keyword(s):

Genetic Algorithm ◽

Finite Element ◽

Sheet Metal ◽

Layout Optimization ◽

Finite Element Analyses ◽

Design And Optimization ◽

Fixture Layout ◽

Fixture Layout Optimization ◽

Dimensional Variation

Fixture layout can affect deformation and dimensional variation of sheet metal assemblies. Conventionally, the assembly dimensions are simulated using a large number of finite element analyses, and fixture layout optimization needs significant user intervention and unaffordable iterations of finite element analyses. This paper therefore proposes a fully automated and efficient method of fixture layout optimization based on the combination of 3DCS simulation (for dimensional analyses) and GAOT, a genetic algorithm in optimization toolbox in MATLAB. The locating points, the key elements of a fixture layout, are selected from a much smaller candidate pool thanks to our proposed manufacturing constraints based filtering methods and thus the computational efficiency is greatly improved. Since MATLAB macro commands of 3DCS have been developed to calculate assembly dimensions, the optimization process is fully automated. A case study of inner hood is applied to demonstrate the proposed method. The results show that the proposed method is suitable for generating the optimal fixture layout with excellent efficiency for engineering applications.

Download Full-text

Modeling Variation Propagation of Multi-Station Assembly Systems With Compliant Parts

Volume 3: 6th Design for Manufacturing Conference ◽

10.1115/detc2001/dfm-21190 ◽

2001 ◽

Author(s):

Jaime A. Camelio ◽

S. Jack Hu ◽

Dariusz J. Ceglarek

Keyword(s):

Space Representation ◽

State Space Representation ◽

Automotive Body ◽

Compliant Assembly ◽

Variation Propagation ◽

Sources Of Variation ◽

Dimensional Variation ◽

Compliant Parts ◽

And Performance

Abstract Products made of compliant sheet metals are widely used in automotive, aerospace, appliance and electronics industries. One of the most important challenges for the assembly process of such compliant parts is the assembly dimensional quality, which affects product functionality and performance. This paper develops a methodology to evaluate the dimensional variation propagation in a multi-station compliant assembly system based on linear mechanics and a state space representation. Three sources of variation are analyzed, part variation, fixture variation and weld gun variation. The proposed method is illustrated through a case study on automotive body assembly.

Download Full-text

Variation Propagation Analysis on Compliant Assemblies Considering Contact Interaction

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2752829 ◽

2007 ◽

Vol 129 (5) ◽

pp. 934-942 ◽

Cited By ~ 72

Author(s):

Kang Xie ◽

Lee Wells ◽

Jaime A. Camelio ◽

Byeng D. Youn

Keyword(s):

Contact Interaction ◽

Thermal Deformation ◽

Linear Process ◽

Assembly Process ◽

Physical Processes ◽

Propagation Analysis ◽

Variation Propagation ◽

Highly Nonlinear ◽

Dimensional Variation

Dimensional variation is inherent to any manufacturing process. In order to minimize its impact on assembly products it is important to understand how the variation propagates through the assembly process. Unfortunately, manufacturing processes are complex and in many cases highly nonlinear. Traditionally, assembly process modeling has been approached as a linear process. However, many assemblies undergo highly complex nonlinear physical processes, such as compliant deformation, contact interaction, and welding thermal deformation. This paper presents a new variation propagation methodology considering the compliant contact effect, which will be analyzed through nonlinear frictional contact analysis. Its variation prediction will be accurately and efficiently conducted using an enhanced dimension reduction method. A case study is presented to show the applicability of the proposed methodology.

Download Full-text

Modeling Variation Propagation of Multi-Station Assembly Systems With Compliant Parts

Journal of Mechanical Design ◽

10.1115/1.1631574 ◽

2003 ◽

Vol 125 (4) ◽

pp. 673-681 ◽

Cited By ~ 187

Author(s):

Jaime Camelio ◽

S. Jack Hu ◽

Dariusz Ceglarek

Keyword(s):

Space Representation ◽

Assembly Process ◽

State Space Representation ◽

Automotive Body ◽

Compliant Assembly ◽

Variation Propagation ◽

Sources Of Variation ◽

Dimensional Variation ◽

Compliant Parts ◽

And Performance

Products made of compliant sheet metals are widely used in automotive, aerospace, appliance and electronics industries. One of the most important challenges for the assembly process with compliant parts is dimensional quality, which affects product functionality and performance. This paper develops a methodology to evaluate the dimensional variation propagation in a multi-station compliant assembly system based on linear mechanics and a state space representation. Three sources of variation: part variation, fixture variation and welding gun variation are analyzed. The proposed method is illustrated through a case study on an automotive body assembly process.

Download Full-text