• Steel and Composite Structures
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• v.17 no.6
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• pp.867-890
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• 2014

This paper deals with the geometric nonlinear bending analysis of laminated composite stiffened plates subjected to uniform transverse loading. The eight-noded degenerated shell element and three-noded degenerated curved beam element with five degrees of freedom per node are adopted in the present analysis to model the plate and stiffeners respectively. The Green-Lagrange strain displacement relationship is adopted and the total Lagrangian approach is taken in the formulation. The convergence study of the present formulation is carried out first and the results are compared with the results published in the literature. The stiffener element is reformulated taking the torsional rigidity in an efficient manner. The effects of lamination angle, depth of stiffener and number of layers, on the bending response of the composite stiffened plates are considered and the results are discussed.

• Structural Engineering and Mechanics
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• v.66 no.1
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• pp.27-36
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• 2018

The objective of this work is to analyze geometrically nonlinear static analysis a simply supported laminated composite beam subjected to a non-follower transversal point load at the midpoint of the beam. In the nonlinear model of the laminated beam, total Lagrangian finite element model of is used in conjunction with the Timoshenko beam theory. The considered 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. In the numerical results, the effects of the fiber orientation angles and the stacking sequence of laminates on the nonlinear deflections and stresses of the composite laminated beam are examined and discussed. Convergence study is performed. Also, the difference between the geometrically linear and nonlinear analysis of laminated beam is investigated in detail.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.491-496
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• 2004

The oscillation of the fluid caused by external forces is called sloshing, which occurs in moving vehicles with contained liquid masses, such as aircraft. cars and liquid rocket and so on. This sloshing effect could be a severe problem in vehicle stability and control. So, various baffles are used in order to reduce the sloshing. The Lagrangian, Eulerian and ALE numerical method is widely used on the analysis of sloshing presently. But, these numerical methods are needed so many CPU time. In this study, for the reduction of the sloshing analysis time, me multi.layer perceptron artificial neural network is introduced and analysis results are presented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.335-342
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• 2002

A continuum-based design sensitivity analysis (DSA) method fur non-shape problems is developed for geometrically nonlinear elastic structures. The non-shape problem is characterized by the design variables that are not associated with the domain of system like sizing, material property, loading, and so on. Total Lagrangian formulation with the Green-Lagrange strain and the second Piola-Kirchhoff stress is employed to describe the geometrically nonlinear structures. The spatial domain is discretized using the 4-node isoparametric plane stress/strain elements. The resulting nonlinear system is solved using the Newton-Raphson iterative method. To take advantage of the derived analytical sensitivity In topology optimization, a fast and efficient design sensitivity analysis method, adjoint variable method, is employed and the material property of each element is selected as non-shape design variable. Combining the design sensitivity analysis method and a gradient-based design optimization algorithm, an automated design optimization method is developed. The comparison of the analytical sensitivity with the finite difference results shows excellent agreement. Also application to the topology design optimization problem suggests a very good insight for the layout design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.05a
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• pp.141-153
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• 1995

An incremental Total Lagrangian Formulation is implemented for the finite element analysis of laminated composite pressure vessel with consideration of the material and geometric nonlinearities. For large displacements/large rotations due to geometric nonlinearities, the incremental equations are derived using a quadratic approximation for the increment of the reference vectors in terms of the nodal rotation increments. This approach leads to a complete tangent stiffness matrix. For material nonlinearity, the analysis is performed by using the piecewise linear method, taking account of the nonlinear shear stress-strain relation. The results of numerical tests include the large deflection behavior of the selected composite shell problem. When compared with the previous analysis, tile results are in good agreement with them. As a practical example, filament wound pressure vessel is analyzed with consideration of the geometrically and materially nonlinearity. The numerical results agree fairly well with the existing experimental results.

• Journal of Hydrospace Technology
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• v.1 no.1
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• pp.111-124
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• 1995

An improved analysis model for material nonlinearity induced by elasto-plastic deformation and damage including a large strain response was proposed. The elasto-plastic-damage constitutive model based on the continuum damage mechanics approach was adopted to overcome limitations of the conventional plastic analysis theory. It can manage the anisotropic tonsorial damage evolved during the time-independent plastic deformation process of materials. Updated Lagrangian finite element formulation for elasto-plastic damage coupling problems including large deformation, large rotation and large strain problems was completed to develop a numerical model which can predict all kinds of structural nonlinearities and damage rationally. Finally a finite element analysis code for two-dimensional plane problems was developed and the applicability and validity of the numerical model was investigated through some numerical examples. Calculations showed reasonable results in both geometrical nonlinear problems due to large deformation and material nonlinearity including the damage effect.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.6
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• pp.333-342
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• 2022

The blast analysis method entails the use of an empirical equation and application of the pressure-time history curve as an explosive load. Although this method is efficient owing to its simple model and short run time, previous studies indicate that it may not be appropriate for near-field explosions. In this study, we investigated why different results were observed for the analysis method by considering an RC beam under near-field explosion conditions with the scaled distance of 0.4-1.0 as an example. On this basis, we examined the application range of the empirical analysis method by using the finite element analysis program LS-DYNA. The results indicate that the empirical analysis method based on data from far-field explosion tests underestimates the impulse. Thus, the calculated deflection of the RC beam would be smaller than the measured deflection and arbitrary Lagrangian-Eulerian (ALE) analysis result. The ALE analysis method is more suitable for near-field explosion conditions wherein the structural responses are large.

• 한국기계연구소 소보
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• s.14
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• pp.17-31
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• 1985

The Primary object of this study is to predict rigid carbody's vertical and pitch acceleration and/or displacement frequency response to vertical sinusoidal rail surface irregularities for any specified point of the carbody, and to verify the predictions by means of experiments. The developed computer program also calculates vertical and pith transmissibilities and acceleration spectra. This model can be used for first order analysis of ride behabior. it's main advantage is its simplicity and ease of use. This model can be used for first order analysis of ride quality behabior. It's main advantage is its simplicity and ease of use. The model was designed with 6 degreed of freedom. Equations of motion were derived by Lagrangian method. This calculation was applied to the vertical dynamic analysis in order to pursue a possible improvement of the dynamic performance of co-co locomotive, and results were very useful.

• Journal of Korean Association for Spatial Structures
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• v.3 no.4 s.10
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• pp.85-92
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• 2003

In this work, a finite element model is presented for geometrically non-linear analysis of shell structures. Finite element by using a three-node flat triangular shell element is formulated. The non-linear incremental equilibrium equations are formulated by using an updated Lagrangian formulation and the solutions are obtained with the incremental/iterative Newton-Raphson method and arc length method. Some of results are presented for shell structures. The obtained results are in good agreement with the results available in existing literature.

• Structural Engineering and Mechanics
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• v.7 no.4
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• pp.345-360
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• 1999

A general framework for the nonlinear geometric analysis of elastic space trusses is presented. Both total Lagrangian and finite incremental formulations are derived from the three key ingredients of statics, kinematics and constitutive law. Particular features of the general methodology include the preservation of static-kinematic duality through the concept of fictitious forces and deformations, and an exact description for arbitrarily large displacements, albeit small strain, that can be specialized to any order of geometrical nonlinearity. As for the numerical algorithm, we consider specifically the finite incremental case and suggest the use of a conventional, simple and flexible arc-length based method. Numerical examples are presented to illustrate and validate the accuracy of the approach.