• Geomechanics and Engineering
• /
• 제11권1호
• /
• pp.1-39
• /
• 2016

The finite element method (FEM), discrete element method (DEM), and Discontinuous deformation analysis (DDA) are among the standard numerical techniques applied in computational geo-mechanics. However, in some cases there no possibility for modelling by traditional finite analytical techniques or other mesh-based techniques. The solution presented in the current study as a completely Lagrangian and mesh-free technique is smoothed particle hydrodynamics (SPH). This method was basically applied for simulation of fluid flow by dividing the fluid into several particles. However, several researchers attempted to simulate soil-water interaction, landslides, and failure of soil by SPH method. In fact, this method is able to deal with behavior and interaction of different states of materials (liquid and solid) and multiphase soil models and their large deformations. Soil indicates different behaviors when interacting with water, structure, instrumentations, or different layers. Thus, study into these interactions using the mesh based grids has been facilitated by mesh-less SPH technique in this work. It has been revealed that the fast development, computational sophistication, and emerge of mesh-less particle modeling techniques offer solutions for problems which are not modeled by the traditional mesh-based techniques. Also it has been found that the smoothed particle hydrodynamic provides advanced techniques for simulation of soil materials as compared to the current traditional numerical methods. Besides, findings indicate that the advantages of applying this method are its high power, simplicity of concept, relative simplicity in combination of modern physics, and particularly its potential in study of large deformations and failures.

• Wind and Structures
• /
• 제29권3호
• /
• pp.195-207
• /
• 2019

This paper presents an overview of wind turbine research techniques including the recent application of hybrid testing. Wind turbines are complex structures as they are large, slender, and dynamic with many different operational states, which limits applicable research techniques. Traditionally, numerical simulation is widely used to study turbines while experimental tests are rarer and often face cost and equipment restrictions. Hybrid testing is a relatively new simulation method that combines numerical and experimental techniques to accurately capture unknown or complex behaviour by modelling portions of the structure experimentally while numerically simulating the remainder. This can allow for increased detail, scope, and feasibility in wind turbine tests. Hybrid testing appears to be an effective tool for future wind turbine research, and the few studies that have applied it have shown promising results. This paper presents a literature review of experimental and numerical wind turbine testing, hybrid testing in structural engineering, and hybrid testing of wind turbines. Finally, several applications of hybrid testing for future wind turbine studies are proposed including multi-hazard loading, damped turbines, and turbine failure.

• Geomechanics and Engineering
• /
• 제37권1호
• /
• pp.21-29
• /
• 2024

The effective management of damage in tunnels is crucial for ensuring their safety, longevity, and operational efficiency. In this paper, we propose an educational management model tailored specifically for addressing damage in tunnels, utilizing numerical solution techniques. By leveraging advanced computational methods, we aim to develop a comprehensive understanding of the factors contributing to tunnel damage and to establish proactive measures for mitigation and repair. The proposed model integrates principles of tunnel engineering, structural mechanics, and numerical analysis to facilitate a systematic approach to damage assessment, diagnosis, and management. Through the application of numerical solution techniques, such as finite element analysis, we demonstrate the efficacy of the proposed model in simulating various damage scenarios and predicting their impact on tunnel performance. Additionally, the educational component of the model provides valuable insights and training opportunities for tunnel management personnel, empowering them to make informed decisions and implement effective strategies for ensuring the structural integrity and safety of tunnel infrastructure. Overall, the proposed educational management model represents a significant advancement in tunnel management practices, offering a proactive and knowledge-driven approach to addressing damage and enhancing the resilience of tunnel systems.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2007년 가을학술발표회
• /
• pp.542-557
• /
• 2007

Contamination of subsurface results in degradation of geomaterials (i.e., soils and rock mass), in the long run. This is mainly due to the presence of chemical and/or radiological materials in undesirable concentrations and at elevated temperatures. However, as contaminant-geomaterial interaction is an extremely slow and complex process, which primarily depends on their physical, chemical and mineralogical properties, it is quite difficult to study this interaction under laboratory or in situ conditions. In such a situation, accelerated physical modeling, using a geotechnical centrifuge, and finite element/difference based numerical modeling techniques are found to be quite useful. This paper presents details of various modeling techniques developed by the researchers at the Indian Institute of Technology Bombay, Mumbai, India, for studying heat migration, flow and interaction (fate) of reactive and non-reactive contaminants in the geoenvironment, under saturated and unsaturated conditions. In addition, paper presents details of the technique that can be employed for determining susceptibility of a material to undergo physico-chemico-mineralogical alterations due to its interaction with contaminants.

• 한국철도학회논문집
• /
• 제7권4호
• /
• pp.391-399
• /
• 2004

This paper investigated the dispersion characteristics of horizontal surface waves as means to apply conversional SASW techniques. To verify this proposal, 3D finite element analysis and Transfer matrix solution were performed. SH wave(Love waves) has the some advantages in comparison with Rayleigh wave. Representatively, Love wave has a characteristics not affected by compression wave. These characteristics have the robust applicability for the surface wave investigation techniques. In this study, for the purpose of employing Love wave in the SASW method, the dispersion characteristics of the Love wave was extensively investigated by the theoretical and numerical approaches. The 3-D finite element and transfer matrix analyses for the half space and two-layer systems were performed to determine the phase velocities from Love wave as well as from both the vertical and the horizontal components of Rayleigh wave. Preliminary, numerical simulations and theoretical solutions indicated that the dispersion characteristics of horizontal surface wave(Love waves) can be sufficiently sensitive and appliable to SASW techniques.

• Structural Engineering and Mechanics
• /
• 제18권1호
• /
• pp.59-78
• /
• 2004

This paper is devoted to illustrate some numerical procedures to solve the boundary equilibrium problems of three-dimensional solids that are subjected to thermal strains. The constitutive equations take into account the bounded tensile strength of the material and they are presented in the framework of non-linear elasticity and small strains. The associated equilibrium problem is solved numerically by means of the finite element method and the numerical techniques, i.e. the Newton-Raphson method and the secant method, are revised in order to assure the solution convergence of the discretized problem. Some numerical examples are illustrated.

• Kyungpook Mathematical Journal
• /
• 제61권2호
• /
• pp.383-393
• /
• 2021

In this paper, numerical techniques are presented for solving initial value problems of fractional differential equations with variable coefficients. The method is derived by applying a Taylor vector approximation. Moreover, the operational matrix of fractional integration of a Taylor vector is provided in order to transform the continuous equations into a system of algebraic equations. Furthermore, numerical examples demonstrate that this method is applicable and accurate.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.532-537
• /
• 2005

The techniques of internally generating waves on a curve in a rectangular grid system are developed using the line source method. Numerical experiments are conducted using the extended mild-slope equations of Suh et al. (1997). For five different types of wave generation layout, numerical experiments are conducted in the cases of the propagation of waves on a flat bottom, and the refraction and shoaling of waves on a plane slope. The fifth type of wave generation, which consists of two parallel lines connected to a semicircle, shows the best solutions especially when the grid size is small enough.

• 한국자동차공학회논문집
• /
• 제11권2호
• /
• pp.31-39
• /
• 2003

Numerical analysis for valve train dynamics of an internal combustion engine is presented. The components of the valve train are modeled by finite element techniques, and the dynamic contacts between the components are analyzed by the solution strategies of differential algebraic equations. Also an iterative scheme similar to the augmented Lagrange multiplier method is employed to enforce the contact constraints. It is shown that the contact and separation between the components of the valve train can be computed by the finite element techniques, and the numerical examples are presented to demonstrate the efficiency of the solution.

• 전기학회논문지P
• /
• 제55권2호
• /
• pp.62-66
• /
• 2006

This thesis focuses on the design of control schemes for highly efficient BLDC motor drive applications using drives with output capacity of 1Hp. The control system was designed and implemented on a PIC micro-controller and applied to an electric vehicle as a viable replacement to the existing a high phase induction motor that is currently being used for these low cost, small traction drive applications. This paper for the brushless drive research has shown the optimization of the drive system for improved drive design and switching techniques that can improve the entire drive system efficiency for electric vehicle both large and small traction applications using sinusoidal PWM techniques for synthesizing the AC waveforms needed to control these traction drives. In addition, Numerical simulation was conducted to evaluate the performance of designed BLDC Motor using MotorPro simulator.