• Steel and Composite Structures
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• v.52 no.1
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• pp.57-76
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• 2024

The management of waste tire rubber has become a pressing environmental and health issue, requiring sustainable solutions to mitigate fire hazards and conserve natural resources. The performance of waste materials in structural components needs to be investigated to fabricate sustainable structures. This study aims to investigate the behavior of glass fiber reinforced polymer (GFRP) reinforced rubberized concrete (GRRC) compressive components under compressive loads. Nine GRRC circular compressive components, varying in longitudinal and transverse reinforcement ratios, were constructed. A 3D nonlinear finite element model (FEM) was proposed by means of the ABAQUS software to simulate the behavior of the GRRC compressive components. A comprehensive parametric analysis was conducted to assess the impact of different parameters on the performance of GRRC compressive components. The experimental findings demonstrated that reducing the spacing of GFRP stirrups enhanced the ductility of GRRC compressive components, while the addition of rubberized concrete further improved their ductility. Failure in GRRC compressive components occurred in a compressive columnar manner, characterized by vertical cracks and increased deformability. The finite element simulations closely matched the experimental results. The proposed empirical model, based on 600 test samples and considering the lateral confinement effect of FRP stirrups, demonstrated higher accuracy (R² = 0.835, MSE = 171.296, MAE = 203.549, RMSE = 195.438) than previous models.

• Composites Research
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• v.23 no.6
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• pp.7-13
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• 2010

Type3 cylinder is a composite pressure vessel fully over-wrapped with carbon/epoxy composite layers over an aluminum liner, which is the most ideal and safe high pressure gas container for CNG vehicles due to the lightweight and the leakage-before-burst characteristics. During service in CNG vehicle, if a fiber cut damage occurs in outer composite layers, it can degrade structural performance, reducing cycling life from the original design life. In this study, finite element modeling and analysis technique for the composite cylinder with fiber-cut crack damage is presented. Because FE analysis of type3 cylinder is path dependant due to plastic deformation of aluminum liner in autofrettage process, method to introduce a crack into FE model affect analysis result. A crack should be introduced after autofrettage in analysis step considering real circumstances where crack occurs during usage in service. For realistic simulation of this situation, FE modeling and analysis technique introducing a crack in the middle of analysis step is presented and the results are compared with usual FE analysis which has initial crack in the model from the beginning of analysis. Proposed analysis technique can be used effectively in the evaluation of influence of damage on composite layers of type3 cylinder and establish inspection criteria of composite cylinder in service.

• Journal of Korean Society of Steel Construction
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• v.16 no.3 s.70
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• pp.295-303
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• 2004

In this paper, an improved four-node Reissner-Mindlin plate-bending element with enhanced assumed strain field is presented for the analysis of isotropic and laminated composite plates. To avoid the shear locking and spurious zero energy modes, the transverse shear behavior is improved by the addition of a new enhanced shear strain based on the incompatible displacement mode approach and bubble function. The "standard" enhanced strain fields (Andelfinger and Ramm, 1993) are also employed to improve the in-plane behaviors of the plate elements. The four-node quadrilateral element derived using the first-order shear deformation theory is designated as "14EASP". Several applications are investigated to assess the features and the performances of the proposed element. The results are compared with other finite element solutions and analytical solutions. Numerical examples show that the element is stable, invariant, passes the patch test, and yields good results especially in highly distorted regimes.

• Steel and Composite Structures
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• v.10 no.6
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• pp.541-561
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• 2010

This paper presents finite element analyses, experimental measurements and finite element model updating of an arch type steel laboratory bridge model using semi-rigid connections. The laboratory bridge model is a single span and fixed base structure with a length of 6.1 m and width of 1.1m. The height of the bridge column is 0.85 m and the maximum arch height is 0.95 m. Firstly, a finite element model of the bridge is created in SAP2000 program and analytical dynamic characteristics such as natural frequencies and mode shapes are determined. Then, experimental measurements using ambient vibration tests are performed and dynamic characteristics (natural frequencies, mode shapes and damping ratios) are obtained. Ambient vibration tests are performed under natural excitations such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. Then the finite element model of the bridge is updated using linear elastic rotational springs in the supports and structural element connections to minimize the differences between analytically and experimentally estimated dynamic characteristics. At the end of the study, maximum differences in the natural frequencies are reduced on average from 47% to 2.6%. It is seen that there is a good agreement between analytical and experimental results after finite element model updating. Also, connection percentages of the all structural elements to joints are determined depending on the rotational spring stiffness.

• Steel and Composite Structures
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• v.27 no.3
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• pp.327-335
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• 2018

This paper presents structural assessment of a steel railway bridge for current condition using modal parameter to upgrade finite element modeling in order to gather accurate result. An adequate monitoring, such as acceleration, displacement, strain monitoring, is important tool to understand behavior and to assess structural performance of the structure under surround vibration by means of the dynamic analysis. Evaluation of conditions of an existing steel railway bridge consist of 4 decks, three of them are 14 m, one of them is 9.7 m, was performed with a numerical analysis and a series of dynamic tests. Numerical analysis was performed implementing finite element model of the bridge using SAP2000 software. Dynamic tests were performed by collecting acceleration data caused by surrounding vibrations and dynamic analysis is performed by Operational Modal Analysis (OMA) using collected acceleration data. The acceleration response of the steel bridge is assumed to be governing response quantity for structural assessment and provide valuable information about the current statute of the structure. Modal identification determined based on response of the structure play significant role for upgrading finite element model of the structure and helping structural evaluation. Numerical and experimental dynamic properties are compared and finite element model of the bridge is updated by changing of material properties to reduce the differences between the results. In this paper, an existing steel railway bridge with four spans is evaluated by finite element model improved using operational modal analysis. Structural analysis performed for the bridge both for original and calibrated models, and results are compared. It is demonstrated that differences in natural frequencies are reduced between 0.2% to 5% by calibrating finite element modeling and stiffness properties.

• Steel and Composite Structures
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• v.22 no.4
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• pp.753-775
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• 2016

This paper aims to investigate the demountability of steel column-baseplate connections subjected to monotonic and cyclic loading. This paper presents the finite element analysis of steel column-baseplate connections under monotonic and cyclic loading. The finite element model takes into account the effects of material and geometric nonlinearities. Bauschinger and pinching effects were also included in the developed model, through which degradation of steel yield strength in cyclic loading can be well simulated. The results obtained from the finite element model are compared with the existing experimental results. It is demonstrated that the finite element model accurately predicts the initial stiffness, ultimate bending moment strength of steel column-baseplate connections. The finite element model is utilised to examine the effects of axial load, baseplate thickness, anchor bolt diameter and position on the behaviour of steel column-baseplate connections. The effects of various parameters on the demountability of steel column-baseplate connections are investigated. To achieve a demountable and reusable structure, various design parameters need to be considered. Initial stiffness and moment capacity of steel columnbaseplate connections are compared with design strengths from Eurocode 3. The comparison between finite element analysis and Eurocode 3 indicates that predictions of initial stiffness for semi-rigid connections should be developed and improved design of the connections needs to be used in engineering practice.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.546-551
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• 2010

In this paper, the strain distribution of the bond layer has been compared with the experimental data and analyzed according to the different mesh refinements and element types. The mesh density was changed along the longitudinal direction of adherend, the longitudinal direction of overlapped region, the vertical direction of adherend, the vertical direction of adhesive and the width direction of the joint. In addition, the effect of the different types of element was evaluated using soild, shell and plane strain element. The geometric nonlinear analysis was performed to consider the large deformation of the joint. From the numerical result, at least 2 elements were needed to achieve a reliable result as the solid element used. In case of shell element, the peel strain at x/c=1 showed 22.8% error compared with the experiment but the shear strain showed a good agreement with the experiment within 1.67% error.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.26-35
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• 2019

In this paper, progressive failure analysis is performed on composite joints widely used in various industries such as the aerospace industry. The analysis was conducted on single bolted joints to confirm its reliability and in succession on double-bolted composite joints as well to study the characteristics of progressive failure. Hashin failure criteria and EGDM (energy based gradual degradation model) were used for the analysis. Failure variables are defined by four failure modes, respectively. According to the variables, stiffness degradation has been calculated. As a result of comparing the test and analysis results of single-bolted joints, the error was below 5% and it showed that the analytical results are rather credible. Also, the parametric analysis consequences were obtained conducting the process-progressive failure analysis on the double-bolted composite joints considering edge-distance ratio (e/d ratio) and bolt spacing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.3
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• pp.133-140
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• 2018

This paper is concerned with the 2-D micostructure generation for $Ni-A{\ell}_2O_3$ dual-phase composite materials and the numerical analysis of mechanical characteristic of hierarchical models of microstructure which are defined in terms of the scale of microstructure. The microstructures of dual-phase composite materials were generated by applying the mathematical RMDF(random morphology description functions) technique to a 2-D RVE of composite materials. And, the hierarchical models of microstructure were defined by the number of Gaussian points. Meanwhile, the volume fractions of metal and ceramic particles were set by adjusting the level of RMD functions. The microstructures which were generated by RMDF technique are definitely random even though the total number of Gaussian points is the same. The randomly generated microstructures were applied to a 2-D beam model, and the variation of normal and shear stresses to the scale of microstructure was numerically investigated. In addition, through the crack analyses, the influence of RMDF randomness and Gauss point number on the crack-tip stress is investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.21-29
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• 2017

In this paper, the total procedure for composite laminate mechanical joint (ASTM D5961 Proc. A, B) from fixture design to test analysis was showed. Composite laminate mechanical joints were analyzed using the FEM(Finite Element Method) and compared to test results. A progressive failure analysis was applied to FEM to analyze the failure behavior of test specimens. Three failure theories - maximum stress, maximum strain, and Tsai-Wu were applied to FEM to predict test failure load. General parameters for composite laminate joints were reviewed and the differences of bearing strength were compared with major parameters.