• Steel and Composite Structures
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• 제12권5호
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• pp.413-426
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• 2012

In this paper, nonlinear static analysis of three-dimensional cable stayed bridges is performed for the time dependent materials properties such as creep, shrinkage and aging of concrete and relaxation of cable. Manavgat Cable-Stayed Bridge is selected as an application. The bridge located in Antalya, Turkey, was constructed with balanced cantilever construction method. Total length of the bridge is 202 m. The bridge consists of one $\ddot{e}$ shape steel tower. The tower is at the middle of the bridge span. The construction stages and 3D finite element model of bridge are modeled with SAP2000. Large displacement occurs in these types of bridges so geometric nonlinearity is taken into consideration in the analysis by using P-Delta plus large displacement criterion. The time dependent material strength and geometric variations are included in the analysis. Two different finite element analyses carried out which are evaluated with and without construction stages and results are compared with each other. As a result of these analyses, variation of internal forces such as bending moment, axial forces and shear forces for bridge tower and displacement and bending moment for bridge deck are given with detailed. It is seen that construction stage analysis has a remarkable effect on the structural behavior of the bridge.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1015-1018
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• 2006

In this paper, new topology optimization technique is proposed. It mainly uses the strain energy distributions induced by the mode shapes associated with natural frequencies of the structure and so we can implicitly consider the dynamic characteristics of the structure in the topology optimization process. The strain energy to be minimized is employed as the objective function and the initial volume of structures is adopted as the constraint function. The resizing algorithm devised from the optimality criteria method is used to update the hole size of the cell existing in each finite element. The cantilever beam problem is adopted to test the proposed techniques. From numerical test, it is found to be that the optimum topology of the cantilever produced by the proposed technique has a hugh increase of natural frequency value and the technique is very effective to maximize the fundamental frequency of the structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1065-1070
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• 2006

The beam structure models with an impactor or contact parts under impact forces have teen applied to the design of mechanical and electronic accessories. Switches, hard-disk pick-ups and sensors are typical structural examples of the structure to be designed to colliding with other parts of structures. In this paper, in order to examine the relationships between the changes of the stiffness and damping of the impactor and vibrations of the dynamic characteristics of the impact model of a cantilevered beam with an impactor, impact force of the impactor and response characteristics of the cantilevered beam were analyzed by both numerical simulation and experiment. Since the stiffness and damping of the impactor have high nonlinear characteristics, the contact model using revised Herz-model was established by experiments. Also, the results of numerical analyses for dynamic response and impact force of a cantilevered beam with an impactor have a good agreement with experimental results.

• Computers and Concrete
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• 제1권2호
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• pp.211-226
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• 2004

A relatively simple multiple-vertical-line-element macro model has been incorporated into a standard computer code DRAIN-2D. It was used in blind predictions of seismic response of cantilever RC walls subjected to a series of consequent earthquakes on a shaking table. The model was able to predict predominantly flexural response with relative success. It was able to predict the stiffness and the strength of the pre-cracked specimen and time-history response of the highly nonlinear wall as well as to simulate the shift of the neutral axis and corresponding varying axial force in the cantilever wall. However, failing to identify the rupture of some brittle reinforcement in the third test, the model was not able to predict post-critical, near collapse behaviour during the subsequent response to two stronger earthquakes. The analysed macro model seems to be appropriate for global analyses of complex building structures with RC structural walls subjected to moderate/strong earthquakes. However, it cannot, by definition, be used in refined research analyses monitoring local behaviour in the post critical region.

• Steel and Composite Structures
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• 제19권3호
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• pp.635-659
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• 2015

In this study, natural frequency analysis of a large deflected cantilever laminated composite beam fixed at both ends, which forms the case of a pre-stressed curved beam, is investigated. The laminated beam is considered to have symmetric and asymmetric lay-ups and the effective flexural modulus of the beam is used in the analysis. In order to obtain the pre-stressed composite curved beam case, an external vertical concentrated load is applied at the free end of a cantilever laminated composite beam and then the loading point of the deflected beam is fixed. The non-linear deflection curve of the flexible beam undergoing large deflection is obtained by the Reversion Method. The curved laminated composite beam is modeled by using the Finite Element Method with a straight-beam element approach. The effects of orientation angle and vertical load on the natural frequency parameter for the first four modes are examined and the results obtained are given in graphics. It has been found that the effect of the load parameter, which forms the curved laminated beam, on the natural frequency parameter, almost disappears after a certain value of the load parameter. This certain value differs for each laminated curved beam and each vibration mode.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.690-695
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• 2005

Flexible circular cantilever beams when excited externally introduce a lot of dynamic characteristics. The non-linear elements that these flexible beams develop include non-linearity due to inertia terms, spring, and damping. They show different characteristics of motion from each other. In the modes of lower order, the non-linearity due to spring is prevalent, while the non-linearity due to inertia Is prevalent in the modes of higher order. To analyze these effects the non-linear phenomena are analyzed experimentally. When the response characteristics of non-linear vibration are analyzed using autospectrum, it is possible to analyze the subharmonic and superharmonic mot ion by comparison. The phase change is analyzed using the method of phase portrait and the non-linear characteristics of response characteristics that are developed in flexible structures can be predicted and applied to the stage of design.

• Composites Research
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• 제32권2호
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• pp.102-107
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• 2019

Several studies related to reinforce composites structures in the through thickness direction have been developed along the years. As follows, in this study a new reinforced process is proposed based on previous experimental results using a novel stitching process in T-joints and one-stitched specimens. It was established the need to perform more analysis under standard test methods to obtain a better understanding. FEM analysis were compared after performed mode I interlaminar fracture toughness test, using different stitching patterns to analyze the through thickness strength with reference laminates without stitching. The stitching patterns were defined in $2{\times}2$ and $3{\times}3$, where the upper and lower head of the non-continuous stitching process (I-Fiber) has proven to influence in a higher through thickness strength of the laminate. In order to design the numerical model, cohesive parameters were required to define the surface to surface bonding elements using the cohesive zone method (CZM) and simulate the crack opening behavior from the double cantilever beam (DCB) test.

• Advances in nano research
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• 제12권2호
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• pp.167-183
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• 2022

In this paper, the free and forced vibration analysis of rotating cantilever nanoscale cylindrical beams and tubes is investigated under the external dynamic load to examine the nonlocal effect. A couple of nonlocal strain gradient theories with different beams and tubes theories, involving the Euler-Bernoulli, Timoshenko, Reddy beam theory along with the higher-order tube theory, are assumed to the mathematic model of governing equations employing the Hamilton principle in order to derive the nonlocal governing equations related to the local and accurate nonlocal boundary conditions. The two-dimensional functional graded material (2D-FGM), made by the axially functionally graded (AFG) in conjunction with the porosity distribution in the radial direction, is considered material modeling. Finally, the derived Partial Differential Equations (PDE) are solved via a couple of the generalized differential quadrature element methods (GDQEM) with the Newmark-beta techniques for the time-dependent results. It is indicated that the boundary conditions equations play a crucial task in responding to nonlocal effects for the cantilever structures.

• Advances in aircraft and spacecraft science
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• 제10권2호
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• pp.179-202
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• 2023

This article presents a numerical analysis to investigate the natural frequencies and harmonic response of a perforated cantilever beam attached to two layers of piezoelectric materials by using the finite element method for the first time. The bimorph piezoelectric is composed of 3 layers; two of them at the outer are piezoelectric, and the inner isotropic material. A higher order 3-D 20-node solid element that exhibits quadratic displacement behavior is exploited to discretize the isotropic layer, and coupled piezoelectric 3D element with twenty nodes is used to mesh the top and bottom layers. CIRCU94 element is added to act as a resistor part of the model. The proposed model is validated with previous works. The numerical parametric studies are presented to illustrate the effects of perforation geometry, the number of rows, the resistance on the natural frequencies, frequency response, and power. It is found that the thickness has a positive relationship with the natural frequency. Perforations help in producing higher voltage, and the best shape is rectangular perforations, and to produce higher voltage, two rows of rectangular perforations should be applied.

• 한국안전학회지
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• 제38권2호
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• pp.1-7
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• 2023

Fiber-metal laminates (FMLs) and polymer matrix composites (PMCs) are formed in various ways. In particular, FMLs in which aluminum is laminated as a reinforced layer are widely used. Also, glass fiber-reinforced plastics (GFRPs) are generally applied as fiber laminates. The bonding interface layer between the aluminum and fiber laminate exhibits low strength when subjected to hot press fabrication in the event of delamination fracture at the interface. This study presents a simple method for strengthening the interface bonding between the aluminum metal and GFRP layer of FML composites. The surfaces of the aluminum interface layer are engraved with three kinds of patterns by using the laser machine before the hot press works. Furthermore, the effect of the laser patterns on the interfacial toughness is investigated. The interfacial toughness was evaluated by the energy release rate (G) using an asymmetric double cantilever bending specimen (ADCB). From the experimental results, it was shown that the strip type pattern (STP) has the most proper pattern shape in GFRP/Al FML composites. Therefore, this will be considered a useful method for the safety assessment of FML composite structures.