• Wind and Structures
• /
• v.31 no.1
• /
• pp.75-84
• /
• 2020

The aerostatic stability analysis of a long-span suspension bridge by the Element-free Galerkin (EFG) method is presented in this paper. Nonlinear effects due to wind structure interactions should be taken into account in determining the aerostatic behavior of long-span suspension bridges. The EFG method is applied to investigate torsional divergence of suspension bridges, based on both the three components of wind loads and nonlinearities of structural geometric. Since EFG methods, which are based on moving least-square (MLS) interpolation, require only nodal data, the description of the geometry of bridge structure and boundaries consist of defining a set of nodes. A numerical example involving the three-dimensional EFG model of a suspension bridge with a span length of 888m is presented to illustrate the performance and potential of this method. The results indicate that presented method can effectively be applied for modeling suspension bridge structure and the computed results obtained using present modeling strategy for nonlinear suspension bridge structure under wind flow are encouragingly acceptable.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.4
• /
• pp.295-302
• /
• 2004

In this study the optimization of a NFR suspension is performed using finite element method and experimental modal analysis. NFR suspensions are required to have low compliance modes to allow the slider to comply with the rotating disk, and high tracking stiffness modes to maximize the servo bandwidth of the tracking controller First of all, the dual suspension model is designed based on the characteristics of NFR drives. And the parametric study on the sensitivities of compliance modes and tracking stiffness modes is investigated. Finally, the model satisfying static characteristics is selected and shape optimization is performed to improve dynamic characteristics. A prototype of a NFR suspension is made by etching and modal ekperiment in free state is performed. The results of experiment almost agree with those of finite element method.

• Steel and Composite Structures
• /
• v.13 no.4
• /
• pp.343-365
• /
• 2012

Steel suspension members subjected to tension and bending offer an economical and efficient alternative for many structural problems. This paper is concerned with the elastic and elastic-plastic behaviour of suspension members with bending stiffness subjected to vertical point and uniformly distributed loads. An experimental study is described which focuses on the response of three suspension members with various T-shaped steel hot rolled sections and geometric configurations. The tests enable direct assessment of the influence of a key parameter such as the sag-to-span ratio on the response of suspension members. Detailed nonlinear finite-element models are generated to provide a tool for theoretical analyses and to facilitate further understanding of the behaviour. Results demonstrate that experimentally obtained responses can generally be closely predicted numerically because there are relatively good agreements between finite element and tests results. The results and observations of subsequent numerical parametric studies offer an insight into the key factors that govern the behaviour of suspension members with bending stiffness in the elastic-plastic range.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.576-581
• /
• 2002

The suspension is a structure that supports reading, writing head in information storage device. In order to develop the information storage device of high track density, it is necessary to study about the suspension. To satisfy operation condition of information storage device, the suspension shape is very important since it correlates to dynamic characteristics. Therefore, it is necessary to analyze the dynamic characteristics by using finite element analysis and to optimize the suspension of information storage device using size optimization and topology optimization. The suspension has various modes according to different kinds of frequency bandwidth. Sway mode and second torsion mode are especially critical among them. In this paper, we investigated method to improve bandwidth of sway and second torsion mode of HDD and ODD suspension by using size optimization and topology optimization.

• Transactions of Materials Processing
• /
• v.16 no.3 s.93
• /
• pp.201-209
• /
• 2007

Generally, the forming process of suspension system parts have been considered only considered with the formability and have not been considered with the durability of suspension system. But the durability of suspension system is very important characteristic for the dynamic performance of vehicle. Therefore, the suspension system should be manufactured to consider the durability as well as the formability. This paper is about an optimum forming process design with the effect of section properties to consider the roll durability of torsion beam type suspension. In order to determine the tube hydroforming process for the satisfaction the roll durability, the stamping and hydroforming simulation by finite element method were performed. And the results from finite element analysis and roll durability examination showed the tube hydroforming process of torsion beam is optimized as satisfying the durability performance.

• Steel and Composite Structures
• /
• v.15 no.1
• /
• pp.15-39
• /
• 2013

The sensitivities of a structural response due to variation of its design parameters are prerequisite in the majority of the algorithms used for fundamental problems in engineering as system uncertainties, identification and probabilistic assessments etc. The paper presents the concept of probabilistic sensitivity of suspension bridges with respect to near-fault ground motion. In near field earthquake ground motions, large amplitude spectral accelerations can occur at long periods where many suspension bridges have significant structural response modes. Two different types of suspension bridges, which are Bosporus and Humber bridges, are selected to investigate the near-fault ground motion effects on suspension bridges random response sensitivity analysis. The modulus of elasticity is selected as random design variable. Strong ground motion records of Kocaeli, Northridge and Erzincan earthquakes are selected for the analyses. The stochastic sensitivity displacements and internal forces are determined by using the stochastic sensitivity finite element method and Monte Carlo simulation method. The stochastic sensitivity displacements and responses obtained from the two different suspension bridges subjected to these near-fault strong-ground motions are compared with each other. It is seen from the results that near-fault ground motions have different impacts stochastic sensitivity responses of suspension bridges. The stochastic sensitivity information provides a deeper insight into the structural design and it can be used as a basis for decision-making.

• Journal of the Korean Society for Railway
• /
• v.9 no.6 s.37
• /
• pp.798-803
• /
• 2006

The suspension elements like primary coil spring, yaw damper, body to body damper are core parts of high speed railway bogie and the faults relating to these elements are reported recently. Thus, this study is started to analyze the displacements characteristics of suspension elements of high speed railway rolling-stock for the purpose of preventing the faults and developing the maintenance technology for suspension elements like spring and dampers. For this purpose, we made a plan to measure the displacements of the primary coil spring, yaw damper and body to body damper in actual running condition. We developed the measurement device to measure the longitudinal displacement and angular displacement of suspension elements and installed this device to test suspension elements. Test to measure displacements of suspension elements is conducted in service line of high speed railway. The displacement data which is acquired from the test with actual vehicles was analyzed for its maximum displacement depending on the track sections. As a result of analysis, we obtained the displacement trends occurring with the sections and valuable results like maximum values and the displacement distribution.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.146-153
• /
• 2004

Torsion beam rear suspension has been widely adopted to the rear suspension of vehicle by reason of simple structure and cost competitiveness. Since the kinematic characteristics of torsion beam rear suspension are determined by elastic behavior of torsion beam, quasi-static analysis based on finite element modeling of torsion beam has been conducted to obtain the kinematic parameters of torsion beam rear suspension. In this paper, simple kinematic equations with rear geometric parameters are derived to predict the kinematic behavior of torsion beam rear suspension. The suspension design parameters such as roll center height, roll stiffness, roll steer and roll camber can be easily obtained with the kinematic equations. The suggested kinematic equations are validated from comparison with the test results and solution offered by ADAMS. The suspension design parameters varied with the position of torsion beam are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1583-1588
• /
• 2000

The dynamic characteristics of a HDD suspension system are investigated by finite element analysis and experimental modal analysis. A finite element model of the suspension Type850 was developed for unloaded case. The calculated vibration modes were compared with measurements and agree well in shape and frequency except some local modes. Local thickness and Young's modulus of the finite element model are updated by modal tuning method to develop the precise FE model. A sensitivity matrix of the natural frequencies for some design variables was calculated using finite difference method. Most natural frequencies calculated by the tuned FE model coincide with the measurements and the errors between them are less than 2%.

• Steel and Composite Structures
• /
• v.32 no.2
• /
• pp.189-198
• /
• 2019

This paper aims to study the mechanical performance of three-tower four-span suspension bridges with steel truss girders, including the static and dynamic characteristics of the bridge system, and more importantly, the influence of structural parameters including the side-main span ratio, sag-to-span ratio and the girder stiffness on key mechanical indices. For this purpose, the Oujiang River North Estuary Bridge which is a three-tower four-span suspension bridge with two main spans of 800m under construction in China is taken as an example in this study. This will be the first three-tower suspension bridge with steel truss girders in the world. The mechanical performance study and parametric analysis are conducted based on a validated three-dimensional spatial truss finite element model established for the Oujiang River North Estuary Bridge using MIDAS Civil. It is found that a relatively small side-main span ratio seems to be quite appropriate from the perspective of mechanical performance. And decreasing the sag-to-span ratio is an effective way to reduce the horizontal force subjected to the midtower and improve the antiskid safety of the main cable, while the vertical stiffness of the bridge will be reduced. However, the girder stiffness is shown to be of minimal significance on the mechanical performance. The findings from this paper can be used for design of three-tower suspension bridges with steel truss girders.