Axial deformability of the composite lattice cylindrical shell under compressive loading: Application to a load-carrying spacecraft tubular body

2016 ◽  
Vol 146 ◽  
pp. 201-206 ◽  
Author(s):  
A.V. Lopatin ◽  
E.V. Morozov ◽  
A.V. Shatov
Keyword(s):  
Cylindrical Shell ◽  
Compressive Loading ◽  
Load Carrying ◽  
Tubular Body ◽  
Composite Lattice

scholarly journals Enhancement by Metallic Tube Filling of the Mechanical Properties of Electromagnetic Wave Absorbent Polymethacrylimide Foam

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 372 ◽  
Author(s):  
Leilei Yan ◽  
Wei Jiang ◽  
Chun Zhang ◽  
Yunwei Zhang ◽  
Zhiheng He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electromagnetic Wave ◽  
Energy Absorption ◽  
Structural Integrity ◽  
Compressive Loading ◽  
Metallic Tube ◽  
Foaming Process ◽  
Novel Structure ◽  
Load Carrying ◽  
Tube Filling

By the addition of a carbon-based electromagnetic absorbing agent during the foaming process, a novel electromagnetic absorbent polymethacrylimide (PMI) foam was obtained. The proposed foam exhibits excellent electromagnetic wave-absorbing properties, with absorptivity exceeding 85% at a large frequency range of 4.9–18 GHz. However, its poor mechanical properties would limit its application in load-carrying structures. In the present study, a novel enhancement approach is proposed by inserting metallic tubes into pre-perforated holes of PMI foam blocks. The mechanical properties of the tube-enhanced PMI foams were studied experimentally under compressive loading conditions. The elastic modulus, compressive strength, energy absorption per unit volume, and energy absorption per unit mass were increased by 127.9%, 133.8%, 54.2%, and 46.4%, respectively, by the metallic tube filling, and the density increased only by 5.3%. The failure mechanism of the foams was also explored. We found that the weaker interfaces between the foam and the electromagnetic absorbing agent induced crack initiation and subsequent collapses, which destroyed the structural integrity. The excellent mechanical and electromagnetic absorbing properties make the novel structure much more competitive in electromagnetic wave stealth applications, while acting simultaneously as load-carrying structures.

Square Short Wood Columns Strengthened with FRP Sheets under Compressive Load

2012 ◽  
Vol 256-259 ◽  
pp. 1008-1011
Author(s):  
Yan Mei Zhu ◽  
Shu Cheng Yuan ◽  
Min Hou ◽  
Qing Yuan Wang
Keyword(s):  
Ultimate Strength ◽  
Failure Modes ◽  
Compressive Loading ◽  
Compressive Load ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Strength And Stiffness ◽  
Wood Columns

This paper presents the experimental results of the wood columns externally strengthened with fiber reinforced polymer (FRP) subjected to axial compressive loading. In total, 14 square short wood columns were made, which were reinforced by FRP in two reinforcing arrangements. The main parameters studied in the test were (1) the strengthening materials, i.e. carbon FRP (CFRP), basalt FRP (BFRP) and aramid FRP (AFRP); (2) the reinforcing arrangements, i.e. the full wrapping of FRP and the partial reinforcing arrangement; (3) the layers of FRP sheets applied, i.e. one, two and three. The ultimate strength, load-axial displacements curves, load-strain relationships, and the failure modes of all the columns were presented. The test results show that both types of the reinforcing arrangements could increase the ultimate strength and stiffness of the columns tested greatly. The columns strengthened with two layers of FRP sheets gave higher load carrying capacities when compared to the columns strengthened with one or three layers of FRP sheets. The result confirms that the more layers of FRP sheets, the higher of load carrying capacity; however, the adverse results were shown when three layers of FRP sheets applied. Finally, the result also showed that the full wrapping reinforcing arrangement is more effective than the partial one in enhancing the stiffness.

NUMERICAL INVESTIGATION OF INFLUENCING PARAMETER OF IMPERFECTIONS ON THIN SHORT CARBON STEEL CYLINDRICAL SHELL UNDER AXIAL COMPRESSION

2013 ◽  
Vol 04 (03) ◽  
pp. 1350007
Author(s):  
B. PRABU
Keyword(s):  
Cylindrical Shell ◽  
Carbon Steel ◽  
Surface Area ◽  
Numerical Study ◽  
Cylindrical Shells ◽  
Compressive Loading ◽  
Shell Structures ◽  
Geometrical Parameters ◽  
Thin Cylindrical Shell ◽  
Short Carbon

Thin cylindrical shell structures have wide variety of applications due to their favorable stiffness-to-mass ratio and under axial compressive loading, these shell structures fail by their buckling instability. Hence, their load carrying capacity is decided by its buckling strength which in turn predominantly depends on the geometrical imperfections present on the shell structure. The main aim of the present study is to determine the more influential geometrical parameter out of two geometrical imperfection parameters namely, "the extent of imperfection present over a surface area" and its "amplitude". To account for these geometrical parameters simultaneously, the imperfection pattern is assumed as a dent having the shape of extent of surface area as a nearly square. The side length of extent of surface area can be considered as proportional to extent of imperfection present over an area and the dent depth can be considered as proportional to amplitude of imperfections. For the present numerical study, FE models of thin short carbon steel perfect cylindrical shells with different sizes of dent are generated at 1/3rd and half the height of cylindrical shells and analyzed using ANSYS nonlinear FE buckling analysis.

scholarly journals Extension of the Equivalent Material Concept to Compressive Loading: Combination with LEFM Criteria for Fracture Prediction of Keyhole Notched Polymeric Samples

2021 ◽  
Vol 11 (9) ◽  
pp. 4138
Author(s):  
Ali Reza Torabi ◽  
Kazem Hamidi ◽  
Behnam Shahbazian ◽  
Sergio Cicero ◽  
Filippo Berto
Keyword(s):  
Compressive Loading ◽  
General Purpose ◽  
Equivalent Material ◽  
Notched Specimens ◽  
Compressive Stresses ◽  
Equivalent Material Concept ◽  
Load Carrying ◽  
The Mean ◽  
Polymeric Samples ◽  
Material Concept

This work analyzes, both theoretically and experimentally, the fracture process of square specimens weakened by keyhole notches and subjected to compressive stresses. Two materials are covered: general-purpose polystyrene (GPPS) and poly(methyl methacrylate) (PMMA). Firstly, the load-carrying capacity (LCC) of the specimens is determined experimentally. Then, by using the equivalent material concept (EMC) for compressive conditions coupled with the maximum tangential stress (MTS) and the mean stress (MS) criteria, the LCC of the notched specimens is predicted. The results show that by using the approach proposed in the present investigation, not only can the critical loads in the keyhole notched polymeric specimens be precisely predicted, but also the corresponding compressive critical stress of the two mentioned polymers can be successfully estimated.

POSTBUCKLING DEGRADATION FE ANALYSIS OF STIFFENED COMPOSITE PANELS

2010 ◽  
Vol 10 (04) ◽  
pp. 645-668 ◽  
Author(s):  
J. ANSÓTEGUI ARAICO ◽  
I. ORTIZ DE ZARATE ALBERDI ◽  
F. REBOLLO ARRIBAS
Keyword(s):  
Composite Structures ◽  
Compressive Loading ◽  
Composite Panels ◽  
Adhesively Bonded ◽  
Interface Failure ◽  
Damage Propagation ◽  
Adhesive Interface ◽  
Stiffened Composite Panels ◽  
Load Carrying ◽  
Current Design

The capability of a commercial industrial tool, ABAQUS, to simulate the critical damage mechanisms in stiffened composite panels has been evaluated. The analysis and conclusions are supported by experimental results. The focus is on skin–stringer separation during compressive loading. Results show that the advanced degradation modeling capabilities present in commercial codes today may lead to an accurate characterization of the deep postbuckling range behavior and the collapse of stiffened composite panels. Compared to current design practice, where the first indication of ply failure or the onset of damage propagation is taken as the failure load, the methods used here provide a way to exploit the reserves in composite structures. It is concluded that implementing degradation mechanisms (composite ply and adhesive interface degradation) presents a significant improvement to simulate accurately the deep postbuckling states and collapse for stiffened composite panels with adhesively bonded stringers. The nature of the final loss of load-carrying capacity for this type of structures, by composite ply and adhesive interface failure, driven by postbuckling deformation, makes this simulation approach essential.

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