Dynamic response of elastic thin-walled structures influenced by coupling effects

1994 ◽  
Vol 51 (1) ◽  
pp. 91-105 ◽  
Author(s):  
X. Chen ◽  
K.K. Tamma
2011 ◽  
Vol 80-81 ◽  
pp. 536-541 ◽  
Author(s):  
Yun Dong Sha ◽  
Ji Yong Li ◽  
Zhi Jun Gao

Advanced aircraft and spacecraft structures are exposed to increasingly severe operating environments, including a combination of mechanical, aerodynamic, acoustic and thermal loads. Such loading conditions can cause thin-walled structures to respond in a nonlinear fashion and exhibit complex response characteristics. This paper investigates the dynamic response of pre/post buckled thin-walled structure under high level random acoustic loading. Firstly, different orders of critical buckling temperatures and modal frequencies under alternative temperatures are obtained using Finite Element Method (FEM), and the modal frequency changes in a disorder fashion are discussed in detail. Then with coupled BEM/FEM method, the dynamic responses including transverse displacement, strain and stress of a stiffened rectangular plate under thermo-acoustic loading are simulated. By comparing the response characteristics of the plate in pre/post buckled conditions, some valuable conclusions are derived, which can be used to explain the response behaviours of thin-walled structures.


Author(s):  
Mouhab Meshreki ◽  
Helmi Attia ◽  
József Kövecses

Milling of thin-walled aerospace structures is a critical and challenging process. Available models for the prediction of the effect of the fixture on the dynamic response of flexible workpieces are computationally demanding and fail to represent practical cases for milling of thin-walled structures. Based on the analysis of typical structural components encountered in the aerospace industry, a generalized unit-element, with the shape of an asymmetric pocket, was identified to represent the dynamic response of these components. Accordingly, a computationally efficient dynamic model was developed to predict the dynamic response of typical thin-walled aerospace structures using the Rayleigh–Ritz method. In the formulation of this model, the dynamics of a 3D pocket is represented by an equivalent 2D multispan plate taking into account the effect of deformable fixture supports. The developed model was validated numerically and experimentally for different workpiece geometries and various types of loading. This model resulted in one to two orders of magnitude reduction in computation time when compared with the finite element models, with prediction errors less than 10%. The developed model meets the conflicting requirements of prediction accuracy and computational efficiency needed for interactive fixture design.


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

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 592
Author(s):  
Feng Yue ◽  
Ziyan Wu

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.


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