Papers by Keyword: Dynamic Buckling

Abstract: Taking stress wave propagation into account, the governing equations of composite bar with the clamped-fixed boundary conditions considering FSDT (first order shear deformation theory) are derived on the basis of Reddy’ theory and solved by the variable-separated method. The analytic expression of the critical buckling load is obtained basing on the characteristics of homogeneous linear equations having nonzero-solution. The results of the theoretical study and the numerical calculation indicate that FSDT has influence on dynamic buckling of composite bar, and the critical buckling load is small when FSDT is considered. They also show that the magnitude of effect taken by FSDT is small when the layer angle is big.

Abstract: Taking into account the effects of stress wave and the moment of inertia, the governing equations of composite laminated plate under the axial step load are derived by using Hamilton principle. Based on Variable Separation Method, the analytical expression of the critical dynamic buckling load for symmetry composite laminated plates with one edge fixed and three edges simply-supported can be deduced by considering the characteristics of the buckling solution, and the buckling mode is also acquired. Using MATLAB software, the relationship between the critical load and length can be obtained. The influences of different layer parameters and the order of the mode on the dynamic buckling are discussed.

Abstract: Considering the effect of stress wave, the dynamic buckling of circular cylindrical shells under an axial step load is discussed using the classical shell theories and the state-space technique in the paper. Based on the Hamilton’s principle, the dynamic buckling governing equations of shells are derived and solved with the Rayleigh-Ritz method. If the linear homogeneous equations have a non-trivial solution, the determinant of the coefficient matrix must be equal to zero, so the expression of the critical load on the dynamic buckling is got. The relationship between the critical load and length is obtained by using MATLAB software. The influences of boundary conditions, thickness, the number of circumferential waves and the number of axial waves on the dynamic buckling loads are discussed based on numerical computation.

Abstract: The computer simulation of the dynamic buckling on the cylindrical shell subjected to pulse load was carried out by ABAQUS/Expliect. The value of the rectangle and triangle pulse load is the same and the shape is different, and they are applied on the impact end of the cyclindrical shell. The influence of the load amplitude, the shape of load and the effect of the stress wave on the critical buckling time of cylindrical shell were discussed. The radial displacement curve was obtained which indicates that stress wave propagate along the length of the cylindrical shells, and the curve of strain time history is also acquired which is used to judge bifurcation and give the critical time.

Abstract: Computer simulation on the dynamic buckling of different forms of initial-defect and different boundary conditions plates under axial impact load was carried out by using ABAQUS /Standard.The strain-time history curve of the symmetric point of upper and lower surface is give,they are coincidence before the buckling and suddenly separate when the buckling occur which is called be bifurcation,and the critical buckling time is also acquired. The results indicate that the influence of different initial-defect locations and amplitudes on the dynamic buckling is very great.

Abstract: This paper aims at studying the dynamic buckling characteristic of the fiber composite honeycomb under out-of-plane impact load. It was found that: with the increasing of the wall thickness, both the critical buckling load and the critical failure load of the composite honeycomb will decrease gradually. By increasing the wall aspect, the critical buckling load will decrease, while the critical failure load will increase. However, when the aspect reaches to 3.5,both the above two kinds of load are no longer sensitive to the variation of it.

Abstract: Dynamic buckling of bars under step load was studied by considering the stress wave effect. Straight bars without axial inertia were taken as an example when deformation was small. The buckling solution satisfying the boundary conditions was given by the semi-analytic method. The buckling solution was substituted to the dynamic buckling governing equations. The unified expression of dynamic buckling critical load was obtained by discussing the character of the solution. The dynamic buckling critical load was obtained by calculating the value of when the stress wave propagated to the critical length . The value of dynamic buckling load was 2.5 times the one’s of static buckling load with corresponding equivalent length.

Abstract: Based on the Budiansky-Roth motion criterion, a thin cylinder shell finite element model is established using the finite element software (ABAQUS) to systemically investigate the dynamic bucking behavior of single-walled carbon nanotubes, which is validated by the molecular dynamic model. It is shown that both the magnitude and duration of the impact load have a great influence on the critical buckling load. By comparing the buckling modes, it can be found that the stress wave propagation plays an important role on the buckling deformation. A local axisymmetrical buckling mode is observed at the beginning and then an asymmetrical buckling mode occurs because of the stress wave superposition.

Abstract: Experimental and numerical simulation researches were presented on dynamic buckling behaviors of cylindrical shell subjected to explosion loading.An account is given of some principal observations made from a series of experiments in which steel cylindrical shells were subjected to central impact by 200g cylindrical TNT dynamite with different distances.By means of an finite element computer code LS-DYNA,the nonlinear dynamic response process of the cylindrical shells subjected to explosion loading were numerically simulated with Lagrangian-Eulerian coupling method. The numerical simulation results were in good agreement with experimental data. The results provide a reference for the design of explosion-resisting structures.

Abstract: To study the dynamic buckling characteristics of storage tank subjected to three-dimensional seismic excitation, selecting 50000m³ large vertical floating roof storage tanks as research object, the base isolation system was introduced and allowing for the impact of floating roof. The finite element models of non-isolation and base isolation storage tank were established respectively by ADINA. The seismic responses of these two types of storage tank were calculated and the numerical solutions were compared. The results indicate that the dynamic buckling modes of these two types of storage tank system belong to plastic buckling; base isolation measure can effectively increase the critical load value of dynamic buckling and plasticity yielding, the improve rates up to 38% and 60% respectively. The effectiveness of the base isolation can be verified from the angle of buckling.