Numerical investigation on post-buckling behavior of FGM sandwich plates subjected to in-plane mechanical compression

Do, Vuong Nguyen Van,Lee, Chin-Hyung Elsevier 2018 Ocean engineering Vol.170 No.-

<P><B>Abstract</B></P> <P>This study intends to numerically analyze post-buckling behavior of functionally graded material (FGM) sandwich plates under mechanical edge compression. A simple yet accurate meshless approximation based on the radial point interpolation method (RPIM) and the higher-order shear deformation theory (HSDT) is presented and used to predict the post-buckling responses. The HSDT constructs a von Kármán type nonlinear equation which accounts for both the large deformation and the initial geometric imperfection for imperfect FGM sandwich plate. The field variables are approximated by introducing the radial basis function in a compactly supported form through which the shape functions are constructed without any fitting parameters. A solution procedure which utilizes the modified Newton-Raphson iterative scheme is designed to solve the discretized system equations needed to obtain the post-buckling path. Performance accuracy of the mesh-free approximation is confirmed by the comparative studies, followed by the detailed parametric investigations to elucidate the post-buckling characteristics of FGM sandwich plates subjected to in-plane mechanical compression. Results illustrate that the proposed mesh-free method can be used as a simple and accurate numerical tool for predicting the post-buckling responses of FGM sandwich plates, and the initial geometric imperfection and loading type have significant effects on the post-buckling behavior.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Post-bucking analysis of FGM sandwich plates under in-plane mechanical compression is performed. </LI> <LI> A simple yet accurate mesh-free approximation for the post-buckling analysis is presented. </LI> <LI> An algorithm based on the modified Newton-Raphson iterative scheme for tracing the post-buckling path is developed. </LI> <LI> The proposed mesh-free method can accurately predict the post-buckling responses. </LI> <LI> Initial geometric imperfection and loading type (uniaxial or biaxial) significantly affect the post-buckling behavior. </LI> </UL> </P>

Post-buckling analysis of aorta artery under axial compression loads

Akbas, Seref Doguscan,Mercan, Kadir,Civalek, Omer Techno-Press 2020 Advances in nano research Vol.8 No.3

Buckling and post-buckling cases are often occurred in aorta artery because it affected by higher pressure. Also, its stability has a vital importance to humans and animals. The loss of stability in arteries may lead to arterial tortuosity and kinking. In this paper, post-buckling analysis of aorta artery is investigated under axial compression loads on the basis of Euler-Bernoulli beam theory by using finite element method. It is known that post-buckling problems are geometrically nonlinear problems. In the geometrically nonlinear model, the Von Karman nonlinear kinematic relationship is employed. Two types of support conditions for the aorta artery are considered. The considered non-linear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The aorta artery is modeled as a cylindrical tube with different average diameters. In the numerical results, the effects of the geometry parameters of aorta artery on the post-buckling case are investigated in detail. Nonlinear deflections and critical buckling loads are obtained and discussed on the post-buckling case.

Post-buckling finite strip analysis of thick functionally graded plates

Hajikazemi, M.,Ovesy, H.R.,Assaee, H.,Sadr, M.H. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.5

In this paper, a novel semi-energy finite strip method (FSM) is developed based on the concept of first order shear deformation theory (FSDT) in order to attempt the post-buckling solution for thin and relatively thick functionally graded (FG) plates under uniform end-shortening. In order to study the effects of through-the-thickness shear stresses on the post-buckling behavior of FG plates, two previously developed finite strip methods, i.e., semi-energy FSM based on the concept of classical laminated plate theory (CLPT) and a CLPT full-energy FSM, are also implemented. Moreover, the effects of aspect ratio on initial post-buckling stiffness of FG rectangular plates are studied. It has been shown that the variation of the ratio of initial post-buckling stiffness to pre-buckling stiffness ($S^*/S$) with respect to aspects ratios is quite independent of volume fractions of constituents in thin FG plates. It has also been seen that the universal curve representing the variation of ($S^*/S$) with aspect ratio of a FG plate demonstrate a saw shape curve. Moreover, it is revealed that for the thin FG plates in contrast to relatively thick plates, the variations of non-dimensional load versus end-shortening is independent of ceramic-metal volume fraction index. This means that the post-buckling behavior of thin FG plates and the thin pure isotropic plates is similar. The results are discussed in detail and compared with those obtained from finite element method (FEM) of analysis. The study of the results may have a great influence in design of FG plates encountering post-buckling behavior.

Post-buckling analysis of Timoshenko beams with temperature-dependent physical properties under uniform thermal loading

Seref Doguscan Akbas,Turgut Kocatürk 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.1

Post-buckling behavior of Timoshenko beams subjected to uniform temperature rising with temperature dependent physical properties are studied in this paper by using the total Lagrangian Timoshenko beam element approximation. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces end therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young’s modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The beams considered in numerical examples are made of Austenitic Stainless Steel (316). The convergence studies are made. In this study, the difference between temperature dependent and independent physical properties are investigated in detail in post-buckling case. The relationships between deflections, thermal post-buckling configuration, critical buckling temperature, maximum stresses of the beams and temperature rising are illustrated in detail in post-buckling case.

Post-buckling finite strip analysis of thick functionally graded plates

M. Hajikazemi,H.R. Ovesy,H. Assaee,M.H. Sadr 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.5

In this paper, a novel semi-energy finite strip method (FSM) is developed based on the concept of first order shear deformation theory (FSDT) in order to attempt the post-buckling solution for thin and relatively thick functionally graded (FG) plates under uniform end-shortening. In order to study the effects of through-the-thickness shear stresses on the post-buckling behavior of FG plates, two previously developed finite strip methods, i.e., semi-energy FSM based on the concept of classical laminated plate theory (CLPT) and a CLPT full-energy FSM, are also implemented. Moreover, the effects of aspect ratio on initial post-buckling stiffness of FG rectangular plates are studied. It has been shown that the variation of the ratio of initial post-buckling stiffness to pre-buckling stiffness (S*/S) with respect to aspects ratios is quite independent of volume fractions of constituents in thin FG plates. It has also been seen that the universal curve representing the variation of (S*/S) with aspect ratio of a FG plate demonstrate a saw shape curve. Moreover, it is revealed that for the thin FG plates in contrast to relatively thick plates, the variations of nondimensional load versus end-shortening is independent of ceramic-metal volume fraction index. This means that the post-buckling behavior of thin FG plates and the thin pure isotropic plates is similar. The results are discussed in detail and compared with those obtained from finite element method (FEM) of analysis. The study of the results may have a great influence in design of FG plates encountering post-buckling behavior.

Post-buckling analysis of Timoshenko beams with temperature-dependent physical properties under uniform thermal loading

Akbas, Seref Doguscan,Kocaturk, Turgut Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.1

Post-buckling behavior of Timoshenko beams subjected to uniform temperature rising with temperature dependent physical properties are studied in this paper by using the total Lagrangian Timoshenko beam element approximation. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces end therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young's modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The beams considered in numerical examples are made of Austenitic Stainless Steel (316). The convergence studies are made. In this study, the difference between temperature dependent and independent physical properties are investigated in detail in post-buckling case. The relationships between deflections, thermal post-buckling configuration, critical buckling temperature, maximum stresses of the beams and temperature rising are illustrated in detail in post-buckling case.

The Evaluation of the Previous Models Used to Study the Web Post-buckling

Thi-Hang Mai,한상윤,김대혁,강영종 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.3

The number of suggested and modified theories for web post-buckling behavior shows that this is one of the topics receiving much attention in civil engineering. However, the controversy related to the elusive behavior of web post-buckling is going on. The present study using an updated data set from 27 previous experimental shear tests and the current FEA results is to evaluate Basler’s model which represents classical theories and Lee and Yoo’s model which represents recent researches. This research indicates that none of the investigated models provides the accurate prediction of ultimate shear strength in the whole range of practical parameters, they tend to overestimate or underestimate the ultimate shear strength of the girder depending on the aspect ratio of the web panel. Besides, the current FEA results reveal that the in-plane tension field (classical tension field) as in Basler’s theory is not the unique source in web post-buckling reserve and does not characterize the actual behavior of web post-buckling. The reason is that the stresses on two surfaces of the web panel dominate the post-buckling reserve.

Thermal post-buckling analysis of a laminated composite beam

Şeref D. Akbaş 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.4

The purpose of this study is to investigate thermal post-buckling analysis of a laminated composite beam subjected under uniform temperature rising with temperature dependent physical properties. The beam is pinned at both ends and immovable ends. Under temperature rising, thermal buckling and post-buckling phenomena occurs with immovable ends of the beam. In the nonlinear kinematic model of the post-buckling problem, total Lagrangian approach is used in conjunction with the Timoshenko beam theory. Also, material properties of the laminated composite beam are temperature dependent: that is the coefficients of the governing equations are not constant. In the solution of the nonlinear problem, incremental displacementbased finite element method is used with Newton-Raphson iteration method. The effects of the fibber orientation angles, the stacking sequence of laminates and temperature rising on the post-buckling deflections, configurations and critical buckling temperatures of the composite laminated beam are illustrated and discussed in the numerical results. Also, the differences between temperature dependent and independent physical properties are investigated for post-buckling responses of laminated composite beams.

Large post-buckling behavior of Timoshenko beams under axial compression loads

Akbas, Seref D. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.6

Large post-buckling behavior of Timoshenko beams subjected to non-follower axial compression loads are studied in this paper by using the total Lagrangian Timoshenko beam element approximation. Two types of support conditions for the beams are considered. In the case of beams subjected to compression loads, load rise causes compressible forces end therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain displacement relations of the beam. The beams considered in numerical examples are made of lower-Carbon Steel. In the study, the relationships between deflections, rotational angles, critical buckling loads, post-buckling configuration, Cauchy stress of the beams and load rising are illustrated in detail in post-buckling case.

Thermal post-buckling analysis of a laminated composite beam

Akbas, Seref D. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.4

The purpose of this study is to investigate thermal post-buckling analysis of a laminated composite beam subjected under uniform temperature rising with temperature dependent physical properties. The beam is pinned at both ends and immovable ends. Under temperature rising, thermal buckling and post-buckling phenomena occurs with immovable ends of the beam. In the nonlinear kinematic model of the post-buckling problem, total Lagrangian approach is used in conjunction with the Timoshenko beam theory. Also, material properties of the laminated composite beam are temperature dependent: that is the coefficients of the governing equations are not constant. In the solution of the nonlinear problem, incremental displacement-based finite element method is used with Newton-Raphson iteration method. The effects of the fibber orientation angles, the stacking sequence of laminates and temperature rising on the post-buckling deflections, configurations and critical buckling temperatures of the composite laminated beam are illustrated and discussed in the numerical results. Also, the differences between temperature dependent and independent physical properties are investigated for post-buckling responses of laminated composite beams.