• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.1
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• pp.67-80
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• 2004

In the present paper, a numerical algorithm for the kinematic analysis of a MacPherson strut motor-vehicle suspension system is developed. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. The presented formulation in terms of this system of coordinates is simple and involves only elementary mathematics. The resulting constraint equations are mostly either linear or quadratic in the rectangular Cartesian coordinates. The proposed formulation eliminates the need to write redundant constraints and allows to solve a reduced system of equations which leads to better accuracy and a reduction in computing time. The algorithm is applied to solve the initial positions as well as the finite displacement, velocity and acceleration problems for the MacPherson strut motor-vehicle suspension system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.372-377
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• 2004

Tilting bogie system allow the train to pass curve at higher speed without affecting passenger comfort. As the tilting trains offer the optimum means of providing faster and more comfortable rail service with minimum of environmental disturbance and capital investment, mere than 14 countries have now adopted or are about to adopt tilting train technology. The Korean National Railroad is also planing to apply faster tilting train to the areas where the High speed rail service are not provided. This paper describes the parametric study to achieve the optimal suspension parameters of the Bogie for 180 km/h Korean Tilting Train(TTX) from the view point of the vertical and lateral vibration reduction.

• Journal of Industrial Technology
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• v.19
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• pp.43-50
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• 1999

Vehicle suspensions can be regarded as interconnection of rigid bodies with kinematic joints and compliance elements such as springs, bushings, and stabilizers. Design of a suspension system requires detailed specification of the interconnection point (or so called hard points) and characteristic values of compliance elements. During the design process, these design variables are determined to meet some prescribed performance targets expressed in terms of SDFs (Static Design Factors), such as toe, camber, compliance steer, etc. This paper elaborates on a systematic approach to achieve optimum design of suspension systems.

• Honam Mathematical Journal
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• v.31 no.1
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• pp.75-85
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• 2009

We show the existence of the nontrivial periodic solution for a class of the system of the nonlinear suspension bridge equations with Dirichlet boundary condition and periodic condition by critical point theory and linking arguments. We investigate the geometry of the sublevel sets of the corresponding functional of the system, the topology of the sublevel sets and linking construction between two sublevel sets. Since the functional is strongly indefinite, we use the linking theorem for the strongly indefinite functional and the notion of the suitable version of the Palais-Smale condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.81-84
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• 1999

For the research of the effects on suspension solution with YBCO and BSCCO for elcectrophoretic deposition to prepare superconducting thick-film wire, it was investigated that the preheating technique for the superconducting powders in vacuum system was used with various solvent solutions of acetone, ethanol, toluene and buthanol for electrophoresis. As a result it was useful to remove the influence of remaining and adsorbed solvent solution which was existed between and on the particle surfaces when the specimens of superconducting wire by electrophoresis were treated in vacuum of 10$\^$-3/ Torr and temperature around 200$^{\circ}C$ in bell-jar system. From the prepared superconducting wire samples, the critical current density, Jc was measured by 4-point prove method in liquid N$_2$ at the value of 10$\^$3/ to 10$\^$4/ A/$\textrm{cm}^2$, respectively, for the YBCO and BSCCO superconducting wires.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.130-138
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• 1997

In this study, to improve the ride and handling characteristics of the vehicle whose hard points have been already fixed, a tuning method of load spring, damper and stabilizer bar is described. For the suspension system of vehicle, optimized design is necessary to satisfy the incompatible two dynamic characteristics which are the ride isolation property between unsprung mass and sprung mass to reduce the excitation from the road and the accurate correring response property to specific steering inputs. To accomplish above aims, we may approach by experimental method, but it requires to sacrifice much time and cost. This paper, therefore, provides a process of suspension development to improve the ride and handling properties by using computer simulation with saving time and cost, and as results, comparaes the dynamic characteristics of the tuned vehicle with the base vehicle not tuned.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.671-676
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• 2005

Spring is one of major suspension part of the light commercial vehicle (LCV). In the manufacturing process it is shot-peened to improve its fatigue strength. In this paper, residual stresses by shot peening were calculated through finite element analysis, and the effects of these residual stresses on fatigue strength of leaf spring were evaluated. Fatigue tests were performed with two kinds of specimens; one is actual leaf spring assembly, and the other is simulated 3-point bending specimen. Fatigue tests were performed under the loading condition that was measured on the proving ground. From the results, the maximum load-fatigue life relation of leaf spring was defined, and test results of 3 point bending specimen are in good agreement with those of leaf spring assembly. The effects of residual stresses by shot peening on fatigue strength of leaf spring is not large in the high load range, however, in the low load range, its effects were not negligible.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.237-247
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• 2011

This paper presents an improved initial force method for determining the initial shape of suspension bridges. After determining the initial shape factors through the force equilibrium conditions of each hanging point, the initial force method was applied with the computed values, each node's coordinates, and unstrained lengths of the cable element as inputs. The unstrained length of each cable element was regarded as a fixed value in each iteration step, unlike in the typical initial force method. This method can be applied to 2D and 3D suspension bridge models. The validity of the present method was demonstrated by comparing the results of the numerical examples.

• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.749-765
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• 2021

Suspension bridges bear large eccentric live loads in rush hours when most vehicles travel in one direction on the left or right side of the bridge. With the increasing number and weight of vehicles and the girder widening, the eccentric live load effect on the bridge behavior, including bending and distortion of the main girder, gets more pronounced, even jeopardizing bridge safety. This study proposes an analytical algorithm based on multi-catenary theory for predicting the suspension bridge responses to eccentric live load via the nonlinear generalized reduced gradient method. A set of governing equations is derived to solve the following unknown values: the girder rigid-body displacement in the longitudinal direction; the horizontal projection lengths of main cable's segments; the parameters of catenary equations and horizontal forces of the side span cable segments and the leftmost segments of middle span cables; the suspender tensions and the bearing reactions. Then girder's responses, including rigid-body displacement in the longitudinal direction, deflections, and torsion angles; suspenders' responses, including the suspender tensions and the hanging point displacements; main cables' responses, including the horizontal forces of each segment; and the longitudinal displacement of the pylons' tower top under eccentric load can be calculated. The response of an exemplar suspension bridge with three spans of 168, 548, and 168 m is calculated by the proposed analytical method and the finite element method in two eccentric live load cases, and their results prove the former's feasibility. The nonuniform distribution of the live load in the lateral direction is shown to impose a greater threat to suspension bridge safety than that in the longitudinal direction, while some other specific features revealed by the proposed method are discussed in detail.

• Steel and Composite Structures
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• v.26 no.2
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• pp.197-211
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• 2018

The study presents the earthquake performance of the Bosphorus Bridge under multi-point earthquake excitation considering the spatially varying site-specific earthquake motions. The elaborate FE model of the bridge is firstly established depending on the new considerations of the used FEM software specifications, such as cable-sag effect, rigid link and gap elements. The modal analysis showed that singular modes of the deck and the tower were relatively effective in the dynamic behavior of the bridge due to higher total mass participation mass ratio of 80%. The parameters and requirements to be considered in simulation process are determined to generate the spatially varying site-specific ground motions. Total number of twelve simulated ground motions are defined for the multi-support earthquake analysis (Mp-sup). In order to easily implement multi-point earthquake excitation to the bridge, the practice-oriented procedure is summarized. The results demonstrated that the Mp-sup led to high increase in sectional forces of the critical components of the bridge, especially tower base section and tensile force of the main and back stay cables. A close relationship between the dynamic response and the behavior of the bridge under the Mp-sup was also obtained. Consequently, the outcomes from this study underscored the importance of the utilization of the multi-point earthquake analysis and the necessity of considering specifically generated earthquake motions for suspension bridges.