• International Journal of Aeronautical and Space Sciences
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• v.8 no.2
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• pp.76-81
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• 2007

The fiber reinforced laminated composite structures are very susceptible to be damaged when they are impacted by foreign objects. To increase the impact resistance of the laminated composite structures, shape memory alloy(SMA) thin film is embedded in the structure. For the numerical impact analysis of SMA hybrid composite structures, SMA modeling tool is developed to consider pseudoelastic effect of SMAs. Moreover, the damage analysis is considered using failure criteria and a simple damage model for reasonable impact analysis. The numerical results are verified with the experimental ones. Impact analyses for composite plate with pre-strained SMAs are numerically performed and the damage areas are investigated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.27-32
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• 2008

The laminated composite materials have been applied to various mechanical structures due to their high performance to weight ratios. In this study, we suggest a stochastic finite element scheme for the probabilistic analysis of the composite laminated plates. The composite materials consist of two different materials which constitute the matrix and fiber. The material properties in the major and minor directions are determined depending on the volume fraction of these two materials. In this study, the elastic modulus and shear modulus are considered as random and the effect of these random properties on the behavior of the composite plate is investigated. We adopt the weighted integral scheme in the formulation, which has been recognized as the most accurate method in the statistical methodologies. For verification of the proposed scheme, Monte Carlo analysis is also performed for the comparison with the proposed scheme.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.75-83
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• 2010

Laminated composite plates have shown their superiority over metals in applications requiring high specific strength, high specific modulus, and so on. Therefore, they have used in various industry. However, they have poor resistance to impact compared to typical metal materials. So, many researchers have investigated about impact behavior of laminated composite plate. To investigate impact behavior of laminated composite plate, we have to calculate contact force between impactor and laminated composite plate at the first. Impactor's equation of motion, plate's equation of motion and correlations for indentation were solved to know the contact force at the same time. In this study, low velocity impact behavior of composite plate was investigated using the finite element program which is involved the classical Hertzian law, Sun's law and Sun & Yang's experimental law and Sun & Tan's experimental law considering the stacking method.

• Journal of Korean Association for Spatial Structures
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• v.6 no.4 s.22
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• pp.45-52
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• 2006

FRP laminated plates have strong material-nonlinearity. Through vibration Analysis of FRP laminated plates, the result of nonlinearity analysis is compared with the result of linearity analysis according to stacking angle and squency. This study is a fundamental study about displacement in nonlinearity dynamic behavior of FRP laminated plates.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.918-923
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• 2008

Since crack detection for laminated composites in-service is effective to improve the structural reliability of laminated composites, it have been tried to detect cracks of laminated composites by various nondestructive methods. An electric potential method is one of the widely used approaches for detection of cracks for carbon fiber composites, since the electric potential method adopts the electric conductive carbon fibers as reinforcements and sensors and the adoption of carbon fibers as sensors does not bring strength reduction induced by embedding sensors into the structures such as optical fibers. However, the application of the electric method is limited only to electrically conductive composite materials. Recently, a piezoelectric method using piezoelectric characteristics of epoxy adhesives has been successfully developed for the adhesive joints because it can monitor continuously the damage of adhesively bonded structures without producing any defects. Polymeric materials for the matrix of composite materials have piezoelectric characteristics similarly to adhesive materials, and the fracture of composite materials should lead to the fracture of polymeric matrix. Therefore, it seems to be valid that the piezoelectric method can be applied to monitoring the damage of composite materials. In this research, therefore, the feasibility study of the damage monitoring for composite materials by piezoelectric method was conducted. Using carbon fiber epoxy composite and glass fiber composite, charge output signals were measured and analyzed during the static and fatigue tests, and the effect of fiber materials on the damage monitoring of composite materials by the piezoelectric method was investigated.

• Structural Engineering and Mechanics
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• v.72 no.2
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• pp.203-216
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• 2019

Reliability analysis of composite structures considering random variation of involved parameters is quite important as composite materials revealed large statistical variations in their mechanical properties. The reliability analysis of such structures by the first order reliability method (FORM) and Monte Carlo Simulation (MCS) based approach involves repetitive evaluations of performance function. The response surface method (RSM) based metamodeling technique has emerged as an effective solution to such problems. In the application of metamodeling for uncertainty quantification and reliability analysis of composite structures; the finite element model is usually formulated by either classical laminate theory or first order shear deformation theory. But such theories show significant error in calculating the structural responses of composite structures. The present study attempted to apply the RSM based MCS for reliability analysis of composite shell structures where the surrogate model is constructed using higher order shear deformation theory (HSDT) of composite structures considering the uncertainties in the material properties, load, ply thickness and radius of curvature of the shell structure. The sensitivity of responses of the shell is also obtained by RSM and finite element method based direct approach to elucidate the advantages of RSM for response sensitivity analysis. The reliability results obtained by the proposed RSM based MCS and FORM are compared with the accurate reliability analysis results obtained by the direct MCS by considering two numerical examples.

• Structural Engineering and Mechanics
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• v.36 no.6
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• pp.745-758
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• 2010

12 typical laminated composite reinforced concrete (RC) walls with different concrete ages and 3 cast-in-place RC walls subjected to low frequency cyclic load were carried out in this study. The failure mode, force-deformation response and energy dissipation capacity of these specimens were investigated. Differences of structural behaviours between composite RC walls and common cast-in-place RC walls were emphasized in the analysis. The compatibility of the composite specimens with different concrete ages was discussed based on the experiment. Test results indicated that the differences between the lateral bearing capacity and the displacement ductility of the composite walls and the common walls were not so obvious. Some of the composite specimen even has higher bearing capacity under the experiment loading situation. Besides, the two parts of the laminated composite specimens demonstrates incompatibility at the later loading sequence on failure mode and strain response when it is in tension. Finally, this laminated composite shear walls are suggested to be applied in rapid reconstruction structures which is not very high.

• Composites Research
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• v.17 no.1
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• pp.18-28
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• 2004

In order to evaluate the strength of carbody structures of railway rolling stock made of laminated fiber-reinforced composite materials, total laminate approach was introduced. Structural analyses were conducted to check the basic design of hybrid composite carbody structures of the Korean Tilting Train eXpress(TTX) with the service speed of 180km/h. The mechanical tests were also conducted to obtain strengths of composite laminates. The results show that all stress components of composite carbody structures are inside of failure envelopes and total laminate approach is recommended to predict the failure of hybrid composite carbody structures at the stage of the basic design.

• Steel and Composite Structures
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• v.15 no.1
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• pp.57-79
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• 2013

This paper studies the dynamic instability of laminated composite plates under thermal and arbitrary in-plane periodic loads using first-order shear deformation plate theory. The governing partial differential equations of motion are established by a perturbation technique. Then, the Galerkin method is applied to reduce the partial differential equations to ordinary differential equations. Based on Bolotin's method, the system equations of Mathieu-type are formulated and used to determine dynamic instability regions of laminated plates in the thermal environment. The effects of temperature, layer number, modulus ratio and load parameters on the dynamic instability of laminated plates are investigated. The results reveal that static and dynamic load, layer number, modulus ratio and uniform temperature rise have a significant influence on the thermal dynamic behavior of laminated plates.

• Steel and Composite Structures
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• v.22 no.4
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• pp.713-732
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• 2016

A novel four variable refined plate theory is proposed in this work for laminated composite plates. The theory considers a parabolic distribution of the transverse shear strains, and respects the zero traction boundary conditions on the surfaces of the plate without employing shear correction coefficient. The displacement field is based on a novel kinematic in which the undetermined integral terms are used, and only four unknowns are involved. The analytical solutions of antisymmetric cross-ply and angle-ply laminates are determined via Navier technique. The obtained results from the present model are compared with three-dimensional elasticity solutions and results of the first-order and the other higher-order theories reported in the literature. It can be concluded that the developed theory is accurate and simple in investigating the bending and buckling responses of laminated composite plates.