Enhancement of pre-buckling behavior of composite beams with geometric imperfections using piezoelectric actuators

1999 ◽  
Vol 30 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Alfredo Rocha de Faria ◽  
Sérgio Frascino Müller de Almeida
1986 ◽  
Vol 108 (2) ◽  
pp. 131-137
Author(s):  
D. Moulin

This paper presents a simplified method to analyze the buckling of thin structures like those of Liquid Metal Fast Breeder Reactors (LMFBR). The method is very similar to those used for the buckling of beams and columns with initial geometric imperfections, buckling in the plastic region. Special attention is paid to the strain hardening of material involved and to possible unstable post-buckling behavior. The analytical method uses elastic calculations and diagrams that account for various initial geometric defects. An application of the method is given. A comparison is made with an experimental investigation concerning a representative LMFBR component.


2021 ◽  
Vol 162 ◽  
pp. 107542
Author(s):  
Alexandre Rossi ◽  
Alex Sander Clemente de Souza ◽  
Renato Silva Nicoletti ◽  
Carlos Humberto Martins

2018 ◽  
Vol 191 ◽  
pp. 00008
Author(s):  
Ikram Feddal ◽  
Abdellatif Khamlichi ◽  
Koutaiba Ameziane

The use of composite stiffened panels is common in several activities such as aerospace, marine and civil engineering. The biggest advantage of the composite materials is their high specific strength and stiffness ratios, coupled with weight reduction compared to conventional materials. However, any structural system may reach its limit and buckle under extreme circumstances by a progressive local failure of components. Moreover, stiffened panels are usually assembled from elementary parts. This affects the geometric as well as the material properties resulting in a considerable sensitivity to buckling phenomenon. In this work, the buckling behavior of a composite stiffened panel made from carbon Epoxy Prepregs is studied by using the finite element analysis under Abaqus software package. Different plies orientations sets were considered. The initial distributed geometric imperfections were modeled by means of the first Euler buckling mode. The nonlinear Riks method of analysis provided by Abaqus was applied. This method enables to predict more consistently unstable geometrically nonlinear induced collapse of a structure by detecting potential limit points during the loading history. It was found that plies orientations of the composite and the presence of geometric imperfections have huge influence on the strength resistance.


Author(s):  
Ken Susanto ◽  
Bingen Yang

A model is described for predicting quasi-static behavior of a piezoelectric forceps actuator (PFA), which consists of two slightly curved composite beams with bonded piezoelectric layers. The PFA is an innovative medical device that is potentially useful for minimum invasive surgery. The PFA model is compared to the deflection measurements made by a curvature sensor in experiments. This model, with a slight modification, can also be applied to other types of piezoelectric actuators with curved structural components.


Author(s):  
Hui-Shen Shen

Compressive post-buckling under thermal environments and thermal post-buckling due to uniform temperature field or heat conduction are presented for a shear deformable functionally graded cylindrical shell with piezoelectric fiber reinforced composite (PFRC) actuators. The material properties of functionally graded materials (FGMs) are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents, and the material properties of both FGM and PFRC layers are assumed to be temperature-dependent. The governing equations are based on a higher order shear deformation shell theory that includes thermopiezoelectric effects. The nonlinear prebuckling deformations and initial geometric imperfections of the shell are both taken into account. A singular perturbation technique is employed to determine buckling loads (temperature) and post-buckling equilibrium paths. The numerical illustrations concern the compressive and thermal post-buckling behavior of perfect and imperfect FGM cylindrical shells with fully covered PFRC actuators under different sets of thermal and electric loading conditions, from which results for monolithic piezoelectric actuators are obtained as comparators. The results reveal that, in the compressive buckling case, the control voltage only has a small effect on the post-buckling load-deflection curves of the shell with PFRC actuators, whereas in the thermal buckling case, the effect of control voltage is more pronounced for the shell with PFRC actuators, compared with the results of the same shell with monolithic piezoelectric actuators.


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