Post-Buckling of Stiffened Composite Structures with Delaminations

2006 ◽  
Author(s):  
Nikolaos Kontis ◽  
Richard Butler ◽  
Giles Hunt
Keyword(s):  
Composite Structures ◽  
Post Buckling

Evaluation of In-Plane and Out-of-Plane Stresses in Composite Structures Subjected to Large Displacements/Rotations

2018 ◽  
Author(s):  
Alfonso Pagani ◽  
Riccardo Augello ◽  
Erasmo Carrera
Keyword(s):  
Stress Tensor ◽  
Composite Structures ◽  
Structural Model ◽  
Three Dimensional ◽  
Large Displacements ◽  
Nonlinear Stress ◽  
Out Of Plane ◽  
Post Buckling ◽  
Carrera Unified Formulation ◽  
Laminated Structures

In many engineering applications, such as civil, mechanical and aerospace, large displacements and rotations may occur within the working composite structures, due to the extreme loading conditions that may occur during service. This afflicts the equilibrium states of the structures and could change them, eventually, in a catastrophic manner. Therefore, it may be necessary to predict the nonlinear stress conditions of the laminated structures through numerical simulation, in order to prevent the failure of the entire system. To take into account these conditions, a geometrical nonlinear analysis has to be performed. The nonlinear framework proposed in this work is based on the Carrera Unified Formulation (CUF). CUF is a hierarchical formulation that considers the order of the structural model as an input of the analysis, so that no specific formulations are needed to obtain any refined model. The possibility to generate high-order structural elements makes possible to analyze any loading cases, including the post-buckling situation. Furthermore, this methodology allows to evaulate of the full three-dimensional stress tensor in laminated structures. In fact, as CUF is able to calculate the stiffness matrix in an automatic manner, there is no need to include any simplification to evaluate the out-of-plane components of the stress tensor.

Analytical study of thermal buckling and post-buckling behavior of composite beams reinforced with SMA by Reddy Bickford theory

2021 ◽  
pp. 1045389X2110116
Author(s):  
Mahshad Fani ◽  
Fathollah Taheri-Behrooz
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Structures ◽  
Volume Fraction ◽  
Thermal Buckling ◽  
Constitutive Law ◽  
Beam Deflection ◽  
Buckling Behavior ◽  
Non Linear ◽  
Post Buckling

Shape memory alloys are used in composite structures due to their shape memory effect and phase transformation. The recovery force of the shape memory alloy improves the post-buckling behavior of the structure. In this study, the thermal buckling and post-buckling of Shape Memory Alloy (SMA) hybrid composite laminated beam subjected to uniform temperature distribution is investigated. To this purpose, considering Von-Karman non-linear strain terms for large deformation, the non-linear equations of SMA reinforced beam based on Reddy Bickford theory have been derived. Besides, the recovery stress of the restrained SMA wires during martensitic transformation was calculated based on the one-dimensional constitutive law of the Brinson’s model. A numerical solution using Galerkin’s method has been presented for solving the nonlinear partial differential equations to obtain the critical buckling temperature and transverse deformation of the beam in the post-buckling region in both symmetric and anti-symmetric layups. The effect of SMA volume fraction, pre-strain, the boundary condition of the beam, stacking sequence, and its geometric properties have been studied. The results show that even by adding a small amount of SMA to the composite, the critical buckling temperature increases significantly, and the beam deflection decreases. Besides, using this theory has an evident effect on the anti-symmetric layup, especially for the thick beams.

scholarly journals Postbuckling Behavior of Functionally Graded Multilayer Graphene Nanocomposite Plate under Mechanical and Thermal Loads on Elastic Foundations

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Pham Hong Cong ◽  
Nguyen Dinh Duc
Keyword(s):  
Composite Structures ◽  
Composite Plates ◽  
Weight Fraction ◽  
Functionally Graded ◽  
Multilayer Graphene ◽  
Thermal Environments ◽  
Reinforced Composite ◽  
Post Buckling ◽  
Plates And Shells ◽  
Graphene Nanocomposite

This paper presents an analytical approach to postbuckling behaviors of functionally graded multilayer nanocomposite plates reinforced by a low content of graphene platelets (GPLs) using the first order shear deformation theory, stress function and von Karman-type nonlinear kinematics and include the effect of an initial geometric imperfection. The weight fraction of GPL nano fillers is assumed to be constant in each individual GPL-reinforced composite (GPLRC). The modified Halpin-Tsai micromechanics model that takes into account the GPL geometry effect is adopted to estimate the effective Young’s modulus of GPLRC layers. The plate is assumed to resting on Pasternak foundation model and subjected to mechanical and thermal loads. The results show the influences of the GPL distribution pattern, weight fraction, geometry, elastic foundations, mechanical and temperature loads on the postbuckling behaviors of FG multilayer GPLRC plates. Keywords: Postbuckling; Graphene nanocomposite plate; First order shear deformation plate theory. References [1] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A. Firsov, Electric filed effect in atomically thin carbon films, Science 306 (2004) 666–669. http://doi.org/ 10.1126/science.1102896.[2] K.S. Novoselov, D. Jiang, F. Schedin, T.J. Booth, V.V. Khotkevich, S.V. Morozov, A.K. Geim, Two-dimensional atomic crystals, Proceedings of the National Academy of Sciences of the United States of America 102 (2005) 10451–10453. https://doi.org/10.1073/pnas.0502848102.[3] C.D. Reddy, S. Rajendran, K.M. Liew, Equilibrium configuration and continuum elastic properties of finite sized graphene, Nanotechnology 17 (2006) 864-870. https://doi. org/10.1088/0957-4484/17/3/042.[4] C. Lee, X.D. Wei, J.W. Kysar, J. Hone, Measurement of the elastic properties and intrinsic strength of monolayer graphene, Science 321 (2008) 385–388. http://doi.org/10.1126/ science.1157996.[5] F. Scarpa, S. Adhikari, A.S. Phani, Effective elastic mechanical properties of single layer graphene sheets, Nanotechnology 20 (2009) 065709. https://doi.org/10.1088/0957-4484/20/6/ 065709.[6] Y.X. Xu, W.J. Hong, H. Bai, C. Li, G.Q. Shi, Strong and ductile poly(vinylalcohol)/graphene oxide composite films with a layered structure, Carbon 47 (2009) 3538–3543. https://doi.org/ 10.1016/j.carbon.2009.08.022.[7] J.R. Potts, D.R. Dreyer, C.W. Bielawski, R.S. Ruoff, Graphene-based polymer nanocomposites, Polymer 52 (2011) 5-25. https://doi.org/10.1016/j .polymer.2010.11.042.[8] T.K. Das, S. Prusty, Graphene-based polymer composites and their applications, Polymer-Plastics Technology and Engineering 52 (2013) 319-331. https://doi.org/10.1080/03602559.2012. 751410.[9] M. Song, J. Yang, S. Kitipornchai, W. Zhud, Buckling and postbuckling of biaxially compressed functionally graded multilayer graphene nanoplatelet-reinforced polymer composite plates, International Journal of Mechanical Sciences 131–132 (2017) 345–355. https://doi.org/10.1016/j.ijmecsci.2017.07.017.[10] H.S. Shen, Y. Xiang, F. Lin, D. Hui, Buckling and postbuckling of functionally graded graphene-reinforced composite laminated plates in thermal environments, Composites Part B 119 (2017) 67-78. https://doi.org/10.1016/j.compositesb.2017. 03.020.[11] H. Wu, S. Kitipornchai, J. Yang, Thermal buckling and postbuckling of functionally graded graphene nanocomposite plates, Materials and Design 132 (2017) 430–441. https://doi.org/10. 1016/j.matdes.2017.07.025.[12] J. Yang, H. Wu, S. Kitipornchai, Buckling and postbuckling of functionally graded multilayer graphene platelet-reinforced composite beams, Composite Structures 161 (2017) 111–118. https://doi.org/10.1016/j.compstruct.2016.11.048.[13] H.S. Shen, Y. Xiang, Y. Fan, Postbuckling of functionally graded graphene-reinforced composite laminated cylindrical panels under axial compression in thermal environments, International Journal of Mechanical Sciences 135 (2018) 398–409. https://doi.org/10.1016/j.ijme csci.2017.11.031.[14] M.D. Rasool, B. Kamran, Stability analysis of multifunctional smart sandwich plates with graphene nanocomposite and porous layers, International Journal of Mechanical Sciences 167 (2019) 105283. https://doi.org/10.1016/j.ijmecs ci.2019.105283.[15] J.J. Mao, W. Zhang, Buckling and post-buckling analyses of functionally graded graphene reinforced piezoelectric plate subjected to electric potential and axial forces, Composite Structures 216 (2019) 392–405. https://doi.org/10.1016/j. compstruct.2019.02.095.[16] P.H. Cong, N.D. Duc, New approach to investigate nonlinear dynamic response and vibration of functionally graded multilayer graphene nanocomposite plate on viscoelastic Pasternak medium in thermal environment, Acta Mechanica 229 (2018) 651-3670. https://doi.org/ 10.1007/s00707-018-2178-3.[17] N.D. Duc, N.D. Lam, T.Q. Quan, P.M. Quang, N.V. Quyen, Nonlinear post-buckling and vibration of 2D penta-graphene composite plates, Acta Mechanica (2019), https://doi.org/10. 1007/s00707-019-02546-0.[18] N.D. Duc, P.T. Lam, N.V. Quyen, V.D. Quang, Nonlinear Dynamic Response and Vibration of 2D Penta-graphene Composite Plates Resting on Elastic Foundation in Thermal Environments, VNU Journal of Science: Mathematics-Physics 35(3) (2019) 13-29. https:// doi.org/10.25073/2588-1124/vnumap. 4371.[19] J.N. Reddy, Mechanics of laminated composite plates and shells; theory and analysis, Boca Raton: CRC Press, 2004.[20] H.S. Shen, A two-step perturbation method in nonlinear analysis of beams, plates and shells, John Wiley & Sons Inc., 2013.

scholarly journals Post-buckling optimization of composite structures using Koiter's method

2016 ◽  
Vol 108 (8) ◽  
pp. 902-940 ◽  
Author(s):  
Søren R. Henrichsen ◽  
Paul M. Weaver ◽  
Esben Lindgaard ◽  
Erik Lund
Keyword(s):  
Composite Structures ◽  
Buckling Optimization ◽  
Post Buckling

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

A Numerical and Experimental Approach for Modeling Porosity Due to Entrapped Air and Volatiles Off-gassing During Manufacturing of Composite Structures

2019 ◽  
Author(s):  
Curtis Hickmott ◽  
Alireza Forghani ◽  
Victoria Hutten ◽  
Evan Lorbiecki ◽  
Frank Palmieri ◽  
...  
Keyword(s):  
Composite Structures ◽  
Experimental Approach ◽  
Entrapped Air
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