• Journal of KSNVE
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• v.7 no.1
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• pp.153-159
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• 1997

In a stiffened plate reinforced on one of its sides by beam type stiffeners, the asymmetry about the plate mid-plane induces coupling between flexural wave and longitudinal wave. In this research interactions between flexural and longitudinal wave motion are analyzed in a stiffened plate which is reinforced only in one direction. The plate is modelled as a beam to which offset spring-mounted masses are attached at regular intervals. Propagation constants of the coupled waves and corresponding characteristic waves are derived by using periodic structure theory, and a computer code is developed. Also, sample calculations are carried out and the results are discussed.

• Composites Research
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• v.13 no.5
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• pp.37-43
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• 2000

In this paper an analytical investigation pertaining to the elastic shear buckling behavior of transversely stiffened orthotropic plate under in-plane shear forces is presented. All edges of plate are assumed to be simply supported and the evenly placed stiffener is considered as a beam element neglecting its torsional rigidity. For the solution of the problem Rayleigh-Ritz method is employed. Using the derived equation, the limit of buckling stress of transversely stiffened plate is suggested as a graphical form. Based on the limit of buckling stress of stiffened plate, graphical form of results for finding the required stiffener rigidity is presented when one and two stiffeners are located, respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.2
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• pp.287-295
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• 1987

The general equation of equilibrium is presented for a stiffened plate on which the stiffeners having rectangular cross-sections are attached by one or both sides with arbitrarily angles. The principle of minimum potential energy is applied using the concept of adjusted-centroid to derive the equilibrium equation for the stiffened plate. Equivalent rigidities in the present theory are in good agreement with the experiments by the vibration method.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.611-621
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• 2009

This paper first reviews the physical meanings and the expressions of two representative strain rate models: CSM (Cowper-Symonds Model) and JCM (Johnson-Cook Model). Since it is known that the CSM and the JCM are suitable for low-intermediate and intermediate-high rate ranges, many studies regarding marine accidents such as ship collision/grounding and explosion in FPSO have employed the CSM. A formula to predict the material constant of the CSM is introduced from literature survey. Numerical simulations with two different material constitutive equations, classical metal plasticity model based on von Mises yield function and micromechanical porous plasticity model based on Gurson yield function, have been carried out for the stiffened plates under impact loading. Simulation results coincide with experimental results better when using the porous plasticity model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.952-956
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• 2004

The soil-structure interactions are caused by the point sources of explosions, deriving piles, compaction of foundations and excavations those are frequently arose in the construction sites. Thus the analysis of soil-structure interactions is one of the most important subjects in the fields of dynamic analysis and vibration control. From this viewpoint, the aim of this study is to collect the basic data for designing foundation structures throughout understanding the dynamic structural behavior, which is embodied by the dynamic analysis of soil-structure systems. In this study, the dynamic analyses of stiffened thick plates subjected to in-plane stress on elastic foundations are carried out. The foundation is modeled as Pasternak foundation that includes the continuity effect of foundations. Also both the Mindlin plate theory and Timoshenko beam-column theory are used for analyzing the thick plates and beams, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.6
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• pp.114-120
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• 1997

To assess the validity of the previously computed finite element analysis results, the photoelastic experiment was carried out to determine stress intensity factors for crack originating from thin section of integrally stiffened plates having discontinuous thickness interface. The stress intensity factors were deter- mined by using linear slope method of photoelastic data. Results are presented as variable thickness geometry factor. $F_{IV}$ , for various crack lengths and thickness ratios. The experimental values of F/ sub IV/are compared with 3-D finite element analysis results. The correlation between experimental values and analysis results is resonably good.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.1
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• pp.121-132
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• 1994

The aim of the present paper is to clarify the damage characteristics fur ship bottom stiffened platings in grounding. For this purpose, a series of tests are performed. A rigid wedge is quasi-statically pushed into the high tensile steel plates with two stiffeners. The aspect ratio of plates(a/B) is in the range from 1.0 to 2.5 and the thickness of plates is in the range from 3.4 to 7.0mm. Also other parameters, namely the shape of wedge tip, wedge angle and property/direction of stiffeners are varied. The test is carried out using the 100ton universal test machine. During the loading. both applied force and length of cutting(penetration) resulting in the grounding force-penetration response are measured.

• Composites Research
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• v.33 no.6
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• pp.377-382
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• 2020

The free vibration characteristics of corrugated laminated composite plates with axial stiffeners is investigated using the Rayleigh-Ritz method. The plate is stiffened by beams with open cross-section area. The equivalent homogenization model is used for the corrugated laminated composite plates. This homogenization model is treated a corrugated plate as an orthotropic plate that has different material properties in two perpendicular directions. The motion of equivalent plate is represented on the basis of the first order shear deformation theory (FSDT) to account for the effect of rotary inertia and transverse shear deformation. Stiffeners are considered as discrete elements to predict the local vibration mode to be generated by the presence of stiffeners. To validate the proposed analytical approach, natural frequencies and vibration mode shapes from the analytical method are compared with those from the FEA by ANSYS.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.117-124
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• 1991

In this paper, a method to overcome inefficiency of the finite element method in the calculation of compressive strength of one-sided stiffened plates, is proposed. In this method the collapse modes of stiffened plates are assumed as follows. a) Overall buckling $\rightarrow$ Overall collapse b) Local buckling $\rightarrow$ Overall collapse c) Local buckling $\rightarrow$ Local collapse In each collapse mode, shape of deflection is assumed, and then elastic large deformation analysis based on the Rayleigh-Ritz method is carried out. One-sided stiffening effect is considered by taking into account of the moment due to eccentricity. Plastic analysis by assuming hinge lines is also carried out. The ultimate strength of a stiffened plate is obtained as the point of intersection of the elastic analysis curve and the plastic one. From this study, it is concluded that the angles between the plastic hinge lines in plastic collapse mode are determined as the ones which give the minimum collapse load, and these angles are different from the ones assumed in the previous studies. Minimum stiffness ratios can also be calculated. Calculated results according to this method show good agreements with the results by the finite element method.

• Structural Engineering and Mechanics
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• v.15 no.6
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• pp.685-704
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• 2003

The buckling and vibration characteristics of stiffened plates subjected to in-plane concentrated edge loading are studied using finite element method. The problem involves the effects of non-uniform stress distribution over the plate. Buckling loads and vibration frequencies are determined for different plate aspect ratios, boundary edge conditions and load positions. The non-uniform stresses may also be caused due to the supports on the edges. The analysis presented determines the initial stresses all over the region considering the pre-buckling stress state for different kinds of loading and edge conditions. In the structural modeling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. The vibration characteristics are discussed and the results are compared with those available in the literature and some interesting new results are obtained.