• Computers and Concrete
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• v.21 no.5
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• pp.495-504
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• 2018

The possibility of earthquakes in vulnerable regions indicates that efficient technique is required for seismic protection of buildings. During the recent decades, the concept is moving towards the insertion of base isolation on seismic prone buildings. So, investigation of structural behavior is a burning topic for buildings to be isolated in base level by bearing device. This study deals with the incorporation of base isolation system and focuses the changes of structural responses for different types of Lead Rubber Bearing (LRB) isolators. A number of sixteen model buildings have been simulated selecting twelve types of bearing systems as well as conventional fixed-base (FB) scheme. The superstructures of the high-rise buildings are represented by finite element assemblage adopting multi-degree of freedoms. Static and dynamic analyses are carried out for FB and base isolated (BI) buildings. The dynamic analysis in finite element package has been performed by the nonlinear time history analysis (THA) based on the site-specific seismic excitation and compared employing eminent earthquakes. The influence of the model type and the alteration in superstructure behavior of the isolated buildings have been duly assessed. The results of the 3D multistory structures show that the lateral forces, displacement, inertia and story accelerations of the superstructure of the seismic prone buildings are significantly reduced due to bearing insertion. The nonlinear dynamic analysis shows 12 to 40% lessening in base shear when LRB is incorporated leading to substantial allowance of horizontal displacement. It is revealed that the LRB isolators might be potential options to diminish the respective floor accelerations, inertia, displacements and base shear whatever the condition coincides. The isolators with lower force intercept but higher isolation period is found to be better for decreasing base shear, floor acceleration and inertia force leading to reduction of structural and non-structural damage. However, LRB with lower isolator period seems to be more effective in dropping displacement at bearing interface aimed at reducing horizontal shift of building structure.

• 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.

• Computers and Concrete
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• v.18 no.5
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• pp.1019-1039
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• 2016

In this paper, a parallel algorithm of nonlinear dynamic analysis of three-dimensional (3D) reinforced concrete (RC) frame structures based on the platform of graphics processing unit (GPU) is proposed. Time integration is performed using Newmark method for nonlinear implicit dynamic analysis and parallelization strategies are presented. Correspondingly, a parallel Preconditioned Conjugate Gradients (PCG) solver on GPU is introduced for repeating solution of the equilibrium equations for each time step. The RC frames were simulated using fiber beam model to capture nonlinear behaviors of concrete and reinforcing bars. The parallel finite element program is developed utilizing Compute Unified Device Architecture (CUDA). The accuracy of the GPU-based parallel program including single precision and double precision was verified in comparison with ABAQUS. The numerical results demonstrated that the proposed algorithm can take full advantage of the parallel architecture of the GPU, and achieve the goal of speeding up the computation compared with CPU.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.52-56
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• 2012

Recently, the pedestrian protection regulations of Europe and Japan are becoming more stringent. However, it is difficult to evaluate the performance of protection because each regulation has different test conditions such as dummy, impact speed and so on. In this study, we construct a finite element model of pedestrian lower legform impactor prescribed in EEVC (European Experimental Vehicle Committee) W/G 10, and performed a impact analysis between the impactor and the front end module of vehicle. The simulations are carried out by using LS-DYNA3D, which is a well-known nonlinear dynamic simulation software. The analysis results according to various impact location show the impact characteristics of the lower legform.

• Journal of the Korean Society of Safety
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• v.17 no.3
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• pp.36-42
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• 2002

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness(NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the virtual proving ground(VPG) approach for obtaining the dynamic characteristics. VPG approach uses a nonlinear, dynamic, finite element code(LS-DYNA3D) which expands the application boundary outside the classic linear, antic assumptions. VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental test results, and the feasibility of the integrated CAE analysis methodology was verified.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.530-533
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• 2009

This study deals with 2D and 3D nonlinear seismic damage analysis of a concrete gravity dam using the finite element program ABAQUS and the concrete damaged plasticity model. 2D and 3D spillway sections of the dam are simulated. First the frequency analysis is conducted to compare the fundamental frequency and estimate the value of damping coefficient. Then the seismic analysis is conducted using the simulated ground acceleration motion. The relative displacement between the crest and bottom of the dam is obtained and compared for the maximum value and occurrence time. The results indicate that the plane-stress assumption gives similar results of maximum relative displacement and final damage distribution with 3D analysis.

• Computers and Concrete
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• v.23 no.2
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• pp.121-131
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• 2019

Due to the heterogeneity nature of the concrete, it is difficult to simulate the hyperdynamic behaviour and crack trajectory of concrete material when subjected to explosion loads. In this paper, a 3D nonlinear numerical study was conducted to simulate the hyperdynamic behaviour of concrete under various loading conditions using Riedel-Hiermaier-Thoma (RHT) model. Detailed calibration was conducted to identify the optimal parameters for the RHT model on the material level. For the component level, the calibrated RHT parameters were used to simulate the failure behaviour of plain concrete (PC) slab under free air blast load. The response was compared with an available experimental result. The results show the proposed numerical model can accurately simulate the crack trajectory and the failure mode of the PC slab under free air blast load.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.93-104
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• 2003

The Disturbed State Concept (DSC) model, with simplified unloading/reloading formulation, is implemented in a nonlinear dynamic finite element program fur porous media named DSC_DYN2D. In this research, the DSC constitutive model is utilized using the HiSS model for relative intact (RI) part and the critical state model for the fully adjusted (FA) part in the material. The general formulation for implementation is developed. The cyclic loading tests from the field load test data on a pile segment were numerically simulated using the finite element program DSC_DYN2D and compared with field measurements and those from the previous analysis with the HiSS model. The DSC predictions show improved agreement with the field behavior of the pile compared to those from the HiSS model. Overall, the computer procedure with the DSC model allows improved and realistic simulation of the complex dynamic soil-structure interaction problems.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.74-79
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• 2000

Integrating a 3D solid modeler with a general purpose FEM code, an automatic nonlinear analysis system of the 3D crack problems has been developed. A geometry model, i.e. a solid containing one or several 3D cracks is defined. Several distributions of local node density are chosen, and then automatically superposed on one another over the geometry model by using the fuzzy knowledge processing. Nodes are generated by the bucketing method, and ten-noded quadratic tetrahedral solid elements are generated by the Delaunay triangulation techniques. The complete finite element(FE) model generated, and a stress analysis is performed. In this system, burden to analysts fur introducing 3D cracks to the FE model as well as fur estimating their fracture mechanics parameters can be dramatically reduced. This paper describes the methodologies to realize such functions, and demonstrates the validity of the present system.

• Composites Research
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• v.30 no.6
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• pp.343-349
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• 2017

A multifield variational formulation is developed for the finite element (FE) cross-sectional analysis of composite beams. The cross-sectional warping displacements and sectional stresses are considered to be the primary variables through the application of Reissner's partially mixed principle. The warping displacements are modeled using generic FE shape functions with nonlinear distribution over the beam section. A generalized Timoshenko level stiffness matrix is derived which incorporates the effects of elastic couplings, transverse shear, and Poisson's deformations. The accuracy of the present analysis is validated for the stiffness constants and elastostatic responses of composite box beams which correlate well with the experimental data and other state-of-the-art approaches.