Analytical and experimental studies on the buckling of laminated thin-walled structures

1987 ◽  
Author(s):  
CHENG WANG ◽  
THEODORE PIAN ◽  
JOHN DUGUNDJI ◽  
PAUL LAGACE
Keyword(s):  
Experimental Studies ◽  
Thin Walled Structures ◽  
Thin Walled

scholarly journals Increasing Damping of Thin-Walled Structures Using Additively Manufactured Vibration Eliminators

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2125 ◽  
Author(s):  
Paweł Dunaj ◽  
Stefan Berczyński ◽  
Karol Miądlicki ◽  
Izabela Irska ◽  
Beata Niesterowicz
Keyword(s):  
Finite Element ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Steel Beam ◽  
Finite Element Models ◽  
Fem Model ◽  
Thin Walled Structures ◽  
Resonance Frequencies ◽  
Thin Walled ◽  
Parametric Analyses

The paper presents a new way to conduct passive elimination of vibrations consisting of covering elements of structures with low dynamic stiffness with polylactide (PLA). The PLA cover was created in 3D printing technology. The PLA cover was connected with the structure by means of a press connection. Appropriate arrangement of the PLA cover allows us to significantly increase the dissipation properties of the structure. The paper presents parametric analyses of the influence of the thickness of the cover and its distribution on the increase of the dissipation properties of the structure. Both analyses were carried out using finite element models (FEM). The effectiveness of the proposed method of increasing damping and the accuracy of the developed FEM models was verified by experimental studies. As a result, it has been proven that the developed FEM model of a free-free steel beam covered with polylactide enables the mapping of resonance frequencies at a level not exceeding 0.6% of relative error. Therefore, on its basis, it is possible to determine the parameters of the PLA cover. Comparing a free-free steel beam without cover with its PLA-covered counterpart, a reduction in the amplitude levels of the receptance function was achieved by up to 90%. The solution was validated for a steel frame for which a 37% decrease in the amplitude of the receptance function was obtained.

scholarly journals Measurements of Forces and Selected Surface Layer Properties of AW-7075 Aluminum Alloy Used in the Aviation Industry after Abrasive Machining

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3707 ◽  
Author(s):  
Matuszak ◽  
Kłonica ◽  
Zagórski
Keyword(s):  
Surface Layer ◽  
Experimental Studies ◽  
Free Surface Energy ◽  
Aviation Industry ◽  
Spring Stiffness ◽  
Abrasive Machining ◽  
Thin Walled Structures ◽  
Axial Forces ◽  
Strongly Connected ◽  
Thin Walled

Measurements of forces during machining, especially thin-walled structures typical of the aviation industry, are important in the aspect of instability caused by vibration. One of the last stages of manufacturing by machining is the finishing treatment and deburring of the product’s edges. Brushes with ceramic fibres are often employed in deburring, especially for large-sized elements specific to the aviation industry due to the possibility of automatic machining directly on machining centres. This study set out to analyse the effect of variable brushing conditions on axial forces and the selected surface layer properties of AW-7075 aluminium alloy. Experimental studies have examined factors such as surface roughness and topography, axial cutting force in ceramic brush treatment and surface free energy in the aspect of adhesive joints. The tested variable process parameters were the fibre material and the adjustment sleeve spring stiffness. Based on the tests, it was found that the axial force applied by the brush was more strongly connected with the spring stiffness rather than the type of bristle. For most cases, an increase in the value of free surface energy after brushing was observed compared to the initial machining which was milling.

scholarly journals Choice substantiation of a folded foundation model via laboratory experiment

2019 ◽  
Vol 1 (52) ◽  
pp. 139-145
Author(s):  
Radomir Timchenko ◽  
Dmytro Krishko ◽  
Iryna Khoruzhenko
Keyword(s):  
Experimental Studies ◽  
Experiment Planning ◽  
Foundation Design ◽  
Basic Principles ◽  
Scientific Experiment ◽  
Thin Walled Structures ◽  
Foundation Model ◽  
Recent Developments ◽  
Thin Walled ◽  
Shell Foundations

The examples of recent developments of foundation thin-walled structures and their applications are presented. It is notedthat the purpose is to develop a method for conducting experimental studies of contact interaction between a folded shellfoundation and a deformed base. The purpose of the laboratory tray research is to determine the optimal characteristics of thesuggested foundation design. The article suggested a method for conducting a laboratory tray experiment to compare the operationof two models of folded shell foundations. The main stages of conducting the scientific experiment have been describedand the basic principles of selecting materials, devices and equipment for carrying out the experiment have been considered.The conduct of the experiment including data recording for each foundation model has been described. As a result,subsidence data for each foundation model have been obtained. The findings have been analyzed; subsidence graphs for eachfoundation design have been built. It is concluded that better distribution of external load to the foundation system elementsis achieved due to the application of a hinged joint of prismatic folds with supporting beams. It has been found that the chosenparameters of the second foundation model complied with the optimized results of the experiment planning and enabledto demonstrate the properties of the foundation system load redistribution better.

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