The optimal control of assembly deviation for large thin-walled structures based on basic deviation patterns

2021 ◽  
pp. 095440542110245
Author(s):  
Chang Gao ◽  
Haidong Yu ◽  
Ke Yuan ◽  
Xinmin Lai
Keyword(s):  
Great Influence ◽  
Optimization Method ◽  
Propagation Model ◽  
Control Points ◽  
Assembly Process ◽  
Thin Walled Structures ◽  
Deviation Propagation ◽  
Thin Walled ◽  
Deviation Pattern ◽  
Assembly Deviation

The deviation vector at arbitrary location of large thin-walled structure caused by manufacturing process is different and has the characteristic of field distribution, which has great influence on the assemble quality. The deviation of each point on the part is not independent, and the final assembly deviation is difficult to be controlled. In this paper, the deviation field of large thin-walled structure is described by the linear combination of a series of basic deviation patterns. The deviation propagation model is established to quantify the contribution of basic deviation patterns between parts and assembly. A new two-step optimization method based on the adjustment of key control points of the part is proposed for the deviation control of large thin-walled structures. Firstly, the effective independent method is employed to obtain the optimal measurement points, which may characterize all basic deviation patterns of the part accurately. Then a new optimization model is developed to determine the key control points for special basic deviation pattern, which have little influence on the other basic deviation patterns. Based on the genetic optimization algorithm, the optimal key control points and the adjusted quantities for special basic deviation pattern are obtained, simultaneously. A case study on the assembly process of two cylindrical thin-walled parts with initial deviations measured by the Laser Scan Device is conducted. The basic deviation pattern with great influence on the deviation of assembly is determined firstly. The key control points and the corresponding adjusted quantities for this basic deviation pattern are calculated. The results indicate that the deviation of the assembled structure may be suppressed by the adjusted deformation of the key control points of parts. It is useful on the deviation control for the assembly process of large thin-walled structures.

scholarly journals Free-Form Optimization of Thin-Walled Structure for Frequency Response Problem

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Masatoshi Shimoda ◽  
Yang Liu
Keyword(s):  
Frequency Response ◽  
Optimization Method ◽  
Free Form ◽  
Error Norm ◽  
Material Derivative ◽  
Shape Gradient ◽  
Thin Walled Structures ◽  
Target Values ◽  
Gradient Function ◽  
Thin Walled

We present a node-based free-form optimization method for designing forms of thin-walled structures in order to control vibration displacements or mode at a prescribed frequency. A squared displacement error norm is introduced at the prescribed surface as the objective functional to control the vibration displacements to target values in a frequency response problem. It is assumed that the thin-walled structure is varied in the normal direction to the surface and the thickness is constant. A nonparametric shape optimization problem is formulated, and the shape gradient function is theoretically derived using the material derivative method and the adjoint variable method. The shape gradient function obtained is applied to the surface of the thin-walled structure as a fictitious traction force to vary the form. With this free-form optimization method, an optimum thin-walled structure with a smooth free-form surface can be obtained without any shape parameterization. The calculated results show the effectiveness of the proposed method for the optimal free-form design of thin-walled structures with vibration mode control.

Compliant assembly deviation analysis of large-scale thin-walled structures in different clamping schemes via ANCF

2019 ◽  
Vol 40 (2) ◽  
pp. 305-317
Author(s):  
Xun Xu ◽  
Haidong Yu ◽  
Yunyong Li ◽  
Xinmin Lai
Keyword(s):  
Large Scale ◽  
Geometrical Parameters ◽  
Plate Element ◽  
Equilibrium Equations ◽  
Assembly Quality ◽  
Content Type ◽  
Thin Walled Structures ◽  
Quadrilateral Plate ◽  
Thin Walled ◽  
Assembly Deviation

Purpose The structure stiffness is greatly affected by the fixture constraints during assembly due to the flexibility of large-scale thin-walled structures. The compliant deformation of structures is usually not consistent for the non-uniform stiffness in various clamping schemes. The purpose of this paper is to investigate the correlation between the assembly quality and the clamping schemes of structures with various initial deviations and geometrical parameters, which is based on the proposed irregular quadrilateral plate element via absolute nodal coordinate formulation (ANCF). Design/methodology/approach Two typical clamping schemes are specified for the large-scale thin-walled structures. Two typical deviation modes are defined in both free and clamping states in the corresponding clamping schemes. The new irregular quadrilateral plate element via ANCF is validated to analyze the compliant deformation of assembled structures. The quasi-static force equilibrium equations are extended considering the factors of clamping constraints and geometric deviations. Findings The initial deviations and geometrical parameters strongly affect the assembly deviations of structures in two clamping schemes. The variation tendencies of assembly deviations are demonstrated in details with the circumferential clamping position and axial clamping position in two clamping schemes, providing guidance to optimize the fixture configuration. The assembly quality of structures with deviations can be improved by configuration synthesis of the clamping schemes. Originality/value Typical over-constraint clamping schemes and deviation modes in clamping states are defined for large-scale thin-walled structures. The plate element via ANCF is extended to analyze the assembly deviations of thin-walled structures in various clamping schemes. Based on the proposed theoretical model, the effects of clamping schemes and initial deviations on the deformation and assembly deviation propagation of structures are investigated.

Optimization method of fixture layout for aeronautical thin‐walled structures with automated riveting

2012 ◽  
Vol 32 (4) ◽  
pp. 323-332 ◽  
Author(s):  
Hui Cheng ◽  
Yuan Li ◽  
Kai‐Fu Zhang ◽  
Chao Luan ◽  
Yan‐Wu Xu ◽  
...  
Keyword(s):  
Optimization Method ◽  
Fixture Layout ◽  
Thin Walled Structures ◽  
Thin Walled

Frame-Monolithic Technology of Construction of Low-Rise Buildings Made of Foam Gypsum and Steel Thin-Walled Structures

2018 ◽  
Vol 762 (8) ◽  
pp. 36-39 ◽  
Author(s):  
B.G. BULATOV ◽  
◽  
R.I. SHIGAPOV ◽  
M.A. IVLEV ◽  
I.V. NEDOSEKO ◽  
...  
Keyword(s):  
Thin Walled Structures ◽  
Thin Walled

scholarly journals Fracture Mechanical Analysis of Thin-Walled Cylindrical Shells with Cracks

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 592
Author(s):  
Feng Yue ◽  
Ziyan Wu
Keyword(s):  
Fracture Mechanics ◽  
Tensile Stress ◽  
Failure Modes ◽  
Cylindrical Shells ◽  
Crack Tip ◽  
Mechanical Analysis ◽  
J Integral ◽  
Thin Walled Structures ◽  
Circumferential Tensile Stress ◽  
Thin Walled

The fracture mechanical behaviour of thin-walled structures with cracks is highly significant for structural strength design, safety and reliability analysis, and defect evaluation. In this study, the effects of various factors on the fracture parameters, crack initiation angles and plastic zones of thin-walled cylindrical shells with cracks are investigated. First, based on the J-integral and displacement extrapolation methods, the stress intensity factors of thin-walled cylindrical shells with circumferential cracks and compound cracks are studied using linear elastic fracture mechanics, respectively. Second, based on the theory of maximum circumferential tensile stress of compound cracks, the number of singular elements at a crack tip is varied to determine the node of the element corresponding to the maximum circumferential tensile stress, and the initiation angle for a compound crack is predicted. Third, based on the J-integral theory, the size of the plastic zone and J-integral of a thin-walled cylindrical shell with a circumferential crack are analysed, using elastic-plastic fracture mechanics. The results show that the stress in front of a crack tip does not increase after reaching the yield strength and enters the stage of plastic development, and the predicted initiation angle of an oblique crack mainly depends on its original inclination angle. The conclusions have theoretical and engineering significance for the selection of the fracture criteria and determination of the failure modes of thin-walled structures with cracks.

Sign in / Sign up

Export Citation Format

Share Document