Machining Deformation Analysis of Aircraft Monolithic Components Based on the Energy Method

Abstract In the process of machining aircraft monolithic components, the initial stress in the blank will cause machining deformation. Based on the energy method, an analytical mathematical model of machining deformation is presented in this paper. The key point is to transform the energy in the removed material into the deformation energy of the part after machining. The initial residual stress of 7050-T7451 aluminum alloy blank and single frame part are used as investigated case in the analytical model. For layer by layer machining, the deformation evolution is closely related to the tensile or compressive properties of the initial stress of removed material. Combined with the change of neutral axis position, The machining deformation is calculated by theoretical model. Then, FEM simulation is carried out to analyze the influence of stiffening ribs on machining deformation utilizing the semi-analytical model of equivalent bending stiffness. Furthermore, experiments are set up to verify the validity of the theory and FEM data. The results indicate that the deformation results of the experiment are consistent with that of theory and FEM model. Deformation is determined by energy of removed material. This paper provides a novel theoretical approaches for the further investigation of this issue.

Download Full-text

Machining deformation analysis of aircraft monolithic components based on the energy method

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-08531-z ◽

2022 ◽

Author(s):

Xiaoming Huang ◽

Xiaoliang Liu ◽

Jiaxing Li ◽

Yongbin Chen ◽

Dechen Wei ◽

...

Keyword(s):

Energy Method ◽

Deformation Analysis ◽

Machining Deformation ◽

Monolithic Components

Download Full-text

An Analytical Model for the Generation of Residual Stresses in Sprayed Coatings Deposited Progressively onto Planar Substrates

Thermal Spray 1997: Proceedings from the United Thermal Spray Conference ◽

10.31399/asm.cp.itsc1997p0813 ◽

1997 ◽

Author(s):

Y.C. Tsui ◽

T.W. Clyne

Keyword(s):

Residual Stress ◽

Analytical Model ◽

Finite Thickness ◽

Misfit Strain ◽

Substrate Thickness ◽

Layer By Layer ◽

Spreadsheet Program ◽

Spray Coatings ◽

Stress Levels ◽

Planar Substrates

Abstract An analytical model has been developed to predict the residual stress distributions in thermal spray coatings on substrates of finite thickness. This is based on the concept of a misfit strain, caused by either the quenching of splats or by differential thermal contraction during cooling. During spraying, the coatings are asssumed to deposit on the substrate in a progressive (layer-by-layer) manner. Although the misfit strain ("the quenching strain") is the same for each successive incremental layer of deposit, this is imposed each time on a "substrate" of changing thickness. The final stress distribution will in general differ from that which would result if the coating were imposed on the substrate (with the same misfit strain) in a single operation. The model is straightforward to apply: for example, it can be implemented using a standard spreadsheet program. The required input data are the quenching strain (or stress), the spraying temperature, material properties and specimen dimensions. Comparisons have been made between the predictions from this model and from a numerical model for two plasma sprayed systems. Good agreement is observed. The effects of varying certain parameters, such as coating thickness, substrate thickness, coating stiffness, etc, are readily explored, so that the model provides a useful tool for controlling residual stress levels. Application of the model to determine the quenching stress, in conjunction with the use of a curvature monitoring technique, is briefly outlined. In addition, an analysis is made of the errors introduced by using Stoney's equation to deduce stress levels from curvature measurements.

Download Full-text

Initial residual stress measurement based on piecewise calculation methods for predicting machining deformation of aeronautical monolithic components

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-020-05493-6 ◽

2020 ◽

Vol 108 (7-8) ◽

pp. 2063-2078

Author(s):

Shuailei Fu ◽

Pingfa Feng ◽

Yuan Ma ◽

Liping Wang

Keyword(s):

Residual Stress ◽

Stress Measurement ◽

Residual Stress Measurement ◽

Calculation Methods ◽

Initial Residual Stress ◽

Machining Deformation ◽

Monolithic Components

Download Full-text

A Simulation Study on the End Milling Operation with Multiple Process Steps of Aeronautical Frame Monolithic Components

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.66-68.569 ◽

2011 ◽

Vol 66-68 ◽

pp. 569-572

Author(s):

Hai Chao Ye ◽

Guo Hua Qin ◽

Cong Kang Wang ◽

Dong Lu

Keyword(s):

End Milling ◽

Machining Process ◽

Deformation Analysis ◽

Tool Paths ◽

Milling Operation ◽

Multiple Process ◽

Monolithic Components ◽

Milling Forces ◽

The Given

Machining deformation has always been a bottleneck issue in the manufacturing field of aeronautical monolithic components. On the base of finite element method, the effect of the process steps and tool paths on the workpiece stiffness and the redistribution of residual stress in the machining process of aeronautical frame monolithic component was investigated under the given fixturing scheme. Thus, the prediction of the workpiece deformation can be carried out in reason. The proposed simulation approach to deformation analysis can be used to observe the true characteristic of milling forces and machining deformations. Therefore, the proposed method can supply the theoretical basis for the determination of the optimal process parameters.

Download Full-text

A New Bump-Type Foil Bearing Structure Analytical Model

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2747638 ◽

2007 ◽

Vol 129 (4) ◽

pp. 1047-1057 ◽

Cited By ~ 55

Author(s):

Sébastien Le Lez ◽

Mihaï Arghir ◽

Jean Frene

Keyword(s):

Analytical Model ◽

Degrees Of Freedom ◽

Load Capacity ◽

Reaction Force ◽

Analytical Models ◽

Experimental Investigations ◽

Underlying Structure ◽

Static System ◽

Theoretical Approaches ◽

Foil Bearing

A gas bearing of bump foil type comprises an underlying structure made of one or several strips of corrugated sheet metal covered by a top foil surface. The fluid film pressure needs to be coupled with the behavior of the structure for obtaining the whole bearing characteristics. Unlike in classical elasto-aerodynamic models, a foil bearing (FB) structure has a very particular behavior due to friction interfaces, bump interactions, and nonisotropic stiffness. Some authors have studied this complex behavior with the help of three-dimensional finite element simulations. These simulations evidenced a lack of reliable analytical models that can be easily implemented in a FB prediction code. The models found in the literature tend to overestimate the foil flexibility because most of them do not consider the interactions between bumps that are highly important. The present work then develops a model that describes the FB structure as a multidegree of freedom system of interacting bumps. Each bump includes three degrees of freedom linked with elementary springs. The stiffnesses of these springs are analytically expressed so that the model can be adjusted for any dimensions and material properties. Once the stiffness matrix of the whole FB structure is obtained, the entire static system is solved taking friction into account. Despite its relative simplicity, comparisons with finite elements simulations for various static load distributions and friction coefficients show a good correlation. This analytical model has been integrated into a foil bearing prediction code. The load capacity of a first generation foil bearing was then calculated using this structure model as well as other simplified theoretical approaches. Significant differences were observed, revealing the paramount influence of the structure on the static and dynamic characteristics of the foil bearing. Some experimental investigations of the static stiffness of the structure were also realized for complete foil bearings. The structure reaction force was calculated for a shaft displacement with zero rotation speed, using either the multidegree of freedom model or the usual stiffness formulas. The comparisons between theoretical and experimental results also tend to confirm the importance of taking into account the bump interactions in determining the response of the structure.

Download Full-text

The Influence of Residual Stress on the Machining Deformation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.426.172 ◽

2012 ◽

Vol 426 ◽

pp. 172-176

Author(s):

Hun Guo

Keyword(s):

Residual Stress ◽

Finite Element ◽

Finite Element Model ◽

Simulation Model ◽

Elasticity Theory ◽

Initial Stress ◽

Fem Simulation ◽

Element Model ◽

Fem Model ◽

Simulation Results

The key problems in 2D FEM simulation such as the establishment of finite element model, the initial stress loading, the distortion appraisal are solved and 2D FEM simulation model is built to analyze the milling distortion caused by the residual stress. The FEM model is verified by the elasticity theory. Some machining cases are simulated by using of the FEM model. The machining distortion caused by residual stress are analyzed and summarized using the simulation results.

Download Full-text