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.

Compliant Assembly Variation Analysis of Scalloped Segment Plates With a New Irregular Quadrilateral Plate Element Via ANCF

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Haidong Yu ◽  
Chunzhang Zhao ◽  
Xinmin Lai
Keyword(s):  
Material Properties ◽  
Large Scale ◽  
Orthotropic Materials ◽  
Geometrical Parameters ◽  
Assembly Process ◽  
Plate Element ◽  
Equilibrium Equations ◽  
Assembly Quality ◽  
Quadrilateral Plate ◽  
Thin Walled

The accurate calculation of deformation during assembly process is important for deviation propagation of large-scale thin-walled hemisphere structures with manufacturing deviations due to the nonuniformed material properties and nonlinear geometrical behavior. In this study, a new irregular quadrilateral plate element based on the absolute nodal coordinate formulation (ANCF) is proposed to discretize the scalloped segment plates with shape deviations. The high-order shape functions of the new element are developed by considering the variable geometrical boundaries. The generalized elastic forces (GEFS) of the new elements for anisotropic and orthotropic materials are derived based on continuum mechanics approach. The bending deviation mode is defined and the evaluation indexes for assembly quality of thin-walled hemisphere structures are proposed. The force equilibrium equations are employed to study the deformation during assembly process for large-scale thin-walled hemisphere structures with multiple scalloped segment plates. The numerical results are compared with that from experimental data and abaqus. The correlation between the assembly quality and the bending deviation, the clamping methods, the geometrical parameters, and the material properties of structures is also investigated.

scholarly journals Modeling and Experimental Validation of the VARTM Process for Thin-Walled Preforms

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2003
Author(s):  
Da Wu ◽  
Ragnar Larsson ◽  
Mohammad S. Rouhi
Keyword(s):  
Shell Model ◽  
Computational Efficiency ◽  
Large Scale ◽  
Strongly Coupled ◽  
Thin Walled Structures ◽  
Simulation Based ◽  
Thin Walled ◽  
High Computational Efficiency ◽  
Insight Into ◽  
Vartm Process

In this paper, recent shell model is advanced towards the calibration and validation of the Vacuum-assisted Resin Transfer Molding (VARTM) process in a novel way. The model solves the nonlinear and strongly coupled resin flow and preform deformation when the 3-D flow and stress problem is simplified to a corresponding 2-D problem. In this way, the computational efficiency is enhanced dramatically, which allows for simulations of the VARTM process of large scale thin-walled structures. The main novelty is that the assumptions of the neglected through-thickness flow and the restricted preform deformation along the normal of preform surface suffice well for the thin-walled VARTM process. The model shows excellent agreement with the VARTM process experiment. With good accuracy and high computational efficiency, the shell model provides an insight into the simulation-based optimization of the VARTM process. It can be applied to either determine locations of the gate and vents or optimize process parameters to reduce the deformation.

scholarly journals Experimental Nondestructive Test for Estimation of Buckling Load on Unstiffened Cylindrical Shells Using Vibration Correlation Technique

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Kaspars Kalnins ◽  
Mariano A. Arbelo ◽  
Olgerts Ozolins ◽  
Eduards Skukis ◽  
Saullo G. P. Castro ◽  
...  
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Cylindrical Shells ◽  
Laser Scanner ◽  
Experimental Tests ◽  
Buckling Load ◽  
Correlation Technique ◽  
Thin Walled Structures ◽  
Instability Point ◽  
Thin Walled

Nondestructive methods, to calculate the buckling load of imperfection sensitive thin-walled structures, such as large-scale aerospace structures, are one of the most important techniques for the evaluation of new structures and validation of numerical models. The vibration correlation technique (VCT) allows determining the buckling load for several types of structures without reaching the instability point, but this technique is still under development for thin-walled plates and shells. This paper presents and discusses an experimental verification of a novel approach using vibration correlation technique for the prediction of realistic buckling loads of unstiffened cylindrical shells loaded under axial compression. Four different test structures were manufactured and loaded up to buckling: two composite laminated cylindrical shells and two stainless steel cylinders. In order to characterize a relationship with the applied load, the first natural frequency of vibration and mode shape is measured during testing using a 3D laser scanner. The proposed vibration correlation technique allows one to predict the experimental buckling load with a very good approximation without actually reaching the instability point. Additional experimental tests and numerical models are currently under development to further validate the proposed approach for composite and metallic conical structures.

Impact Response of Thin-Walled Tubes: A Prospective Review

2012 ◽  
Vol 165 ◽  
pp. 130-134 ◽  
Author(s):  
Fauziah Mat ◽  
K. Azwan Ismail ◽  
S. Yaacob ◽  
O. Inayatullah
Keyword(s):  
Compressive Loading ◽  
Axial Loading ◽  
Geometrical Parameters ◽  
Axial Deformation ◽  
Thin Walled Structures ◽  
Structural Applications ◽  
Thin Walled ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
The Impact

Thin-walled structures have been widely used in various structural applications asimpact energy absorbing devices. During an impact situation, thin-walled tubesdemonstrate excellent capability in absorbing greater energy through plastic deformation. In this paper, a review of thin-walled tubes as collapsible energy absorbers is presented.As a mean of improving the impact energy absorption of thin-walled tubes, the influence of geometrical parameters such as length, diameter and wall thickness on the response of thin-walled tubes under compression axial loading are briefly discussed. Several design improvements proposed by previous researchers are also presented. The scope of this review is mainly focus on axial deformation under quasi-static and dynamic compressive loading. Other deformations, such as lateral indentation, inversion and splitting are considered beyond the scope of this paper. This review is intended to assist the future development of thin-walled tubes as efficient energy absorbing elements.

scholarly journals Fem and Experimental Analysis of Thin-Walled Composite Elements Under Compression

2017 ◽  
Vol 22 (2) ◽  
pp. 393-402 ◽  
Author(s):  
P. Różyło ◽  
P. Wysmulski ◽  
K. Falkowicz
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Numerical Models ◽  
Fem Analysis ◽  
Geometrical Parameters ◽  
Loss Of Stability ◽  
Composite Columns ◽  
Thin Walled Structures ◽  
Operating Stability ◽  
Thin Walled

Abstract Thin-walled steel elements in the form of openwork columns with variable geometrical parameters of holes were studied. The samples of thin-walled composite columns were modelled numerically. They were subjected to axial compression to examine their behavior in the critical and post-critical state. The numerical models were articulately supported on the upper and lower edges of the cross-section of the profiles. The numerical analysis was conducted only with respect to the non-linear stability of the structure. The FEM analysis was performed until the material achieved its yield stress. This was done to force the loss of stability by the structures. The numerical analysis was performed using the ABAQUS® software. The numerical analysis was performed only for the elastic range to ensure the operating stability of the tested thin-walled structures.

Nonlinear Bending Analysis of First-Order Shear Deformable Microscale Plates Using a Strain Gradient Quadrilateral Element

2016 ◽  
Vol 11 (5) ◽  
Author(s):  
R. Ansari ◽  
M. Faghih Shojaei ◽  
A. H. Shakouri ◽  
H. Rouhi
Keyword(s):  
Finite Element ◽  
Strain Gradient ◽  
Strain Gradient Theory ◽  
Geometrical Parameters ◽  
Element Formulation ◽  
Plate Element ◽  
Nonlinear Bending ◽  
First Order ◽  
Quadrilateral Plate ◽  
Shear Deformable

Based on Mindlin's strain gradient elasticity and first-order shear deformation plate theory, a size-dependent quadrilateral plate element is developed in this paper to study the nonlinear static bending of microplates. In comparison with the classical first-order shear deformable quadrilateral plate element, the proposed element needs 15 additional nodal degrees-of-freedom (DOF) including derivatives of lateral deflection and rotations with respect to coordinates, which means a total of 20DOFs per node. Also, the developed strain gradient-based finite-element formulation is general so that it can be reduced to that on the basis of modified couple stress theory (MCST) and modified strain gradient theory (MSGT). In the numerical results, the nonlinear bending response of microplates for different boundary conditions, length-scale factors, and geometrical parameters is studied. It is revealed that by the developed nonclassical finite-element approach, the nonlinear behavior of microplates with the consideration of strain gradient effects can be accurately studied.

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.

Crashworthiness Optimization of a Vertex Fractal Hexagonal Structure

2019 ◽  
Vol 17 (07) ◽  
pp. 1950031 ◽  
Author(s):  
Yong Zhang ◽  
Ning He ◽  
Yubo Hou
Keyword(s):  
Numerical Modeling ◽  
Design Optimization ◽  
Automotive Industry ◽  
Experimental Analysis ◽  
Hexagonal Structure ◽  
Geometrical Parameters ◽  
Energy Absorber ◽  
Crashworthiness Optimization ◽  
Thin Walled Structures ◽  
Thin Walled

Thin-walled structures are used in automotive industry due to their excellent lightweight and crashworthiness properties. This paper proposes a vertex fractal multi-cell hexagonal structure to develop a novel lightweight energy absorber. Experimental analysis and numerical modeling are performed to investigate the crashworthiness of the fractal multi-cell hexagonal structures. The numerical results indicate that fractal configurations and geometrical parameters of the fractal hexagonal structure have significant effect on the crashworthiness. In addition, the multi-objective design optimization is performed to seek the optimal crashworthiness parameters and explore the optimal crashworthiness of the fractal hexagonal structure. The results show that the fractal multi-cell hexagonal structure outperforms non-fractal hexagonal structure.

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