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

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.235-242
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• 2005

This study introduces the Reliability-Based Design Optimization (RBDO) to enhance the kinematic and compliance (K & C) characteristics of automotive suspension system. In previous studies, the deterministic optimization has been performed to enhance the K & C characteristics. Unfortunately, uncertainties in the real world have not been considered in the deterministic optimization. In the design of suspension system, design variables with the uncertainties, such as the bushing stiffness, have a great influence on the variation of the suspension performances. There is a need to quantify these uncertainties and to apply the RBDO to obtain the design, satisfying the target reliability level. In this research, design variables including uncertainties are dealt as random variables and reliability of the suspension performances, which are related the K & C characteristics, are quantified and the RBDO is performed. The RBD-optimum is compared with the deterministic optimum to verify the enhancement in reliability. Thus, the reliability of the suspension performances is estimated and the RBD-optimum, satisfying the target reliability level, is determined.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.6
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• pp.301-308
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• 2014

A suspension bridge is a type of bridge in which the beam is suspended by load-bearing cables. There are two classifications: the self-anchored suspension bridge has the main cable anchored to the bridge girders, and the earth-anchored suspension bridge has the main cable anchored to a large anchorage. Although a suspension bridge is structurally safe, it is prone to be damaged by various actions such as hurricanes, tsunamis and terrorist incidents because its cables are exposed. If damage to a cable eventually leads to the cable rupture, the bridge may collapse. To avoid these accidents, studies on the dynamic behavior of cable bridges due to the cable rupture have been carried out. Design codes specify that the calculated DAF (dynamic amplification factor) should not exceed a certain value. However, it has been difficult to determine DAFs effectively from dynamic analysis, and thus no systematic approach has been suggested. The current study provides a guideline to determine DAFs reliably from the dynamic analysis results and summarizes the results by applying the method to an earth-anchored suspension bridge. In the study, DAFs were calculated at the location of four structural parts, girders, pylons, main cable and hangers, with variations in the rupture time.

• Wind and Structures
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• v.10 no.6
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• pp.543-554
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• 2007

The suspension bridge is situated in an area of complex topography with both open sea and overland turbulence characteristics, and it is subject to frequent typhoon occurrences. This paper investigates experimentally the possible vortex shedding events of the structure under high wind and typhoon conditions. A single-degree-of-freedom model for the vibration of a unit bridge deck section is adopted to determine the amplitude of vibration and to estimate the parameters related to the lifting force in a vortex shedding event. The results of the studies are presented in a companion paper (Law, et al. 2007). In this paper, statistical analysis on the measured responses of the bridge deck shows that the vibration response at the first torsional mode of the structure has a significant increase at and beyond the critical wind speed for vortex shedding as noted in the wind tunnel tests on a section model of the structure.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.909-914
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• 2009

A suspension is the most prior apparatus to decide vehicle's running safety and ride comfort, also the suspension stiffness is the most important parameter for the designing of the vehicle. Providing the strong stiffness with the primary suspension in order to improve the running safety with high speed, but it causes a problem with a curve running performance of a railway vehicle. Therefore, many studies deal with the optimal value of suspension stiffness. In this paper, we aim to optimize the suspension system to improve running safety by varying stiffness values of railway vehicle suspension. We have proceeded an analysis by design variables which are position, length, width, stiffness and damping coefficients of primary and secondary suspension to optimize the suspension characteristics. As a result of the optimization, we verified that the derailment coefficients of inside and outside of wheel are decreased in comparison with initial model.

• Fibers and Polymers
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• v.6 no.4
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• pp.277-283
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• 2005

In order to prepare high molecular weight poly(methyl methacrylate) (PMMA)/silver nanocomposite microspheres, methyl methacrylate was suspension-polymerized in the presence of silver nanoparticles at low temperature with 2,2'-azobis(2,4-dimethylvaleronitrile) as an initiator. The rate of conversion was increased by increasing the initiator concentration. When silver nanoparticles were added, the rate of polymerization decreased slightly. High monomer conversion (about $85\%$) was obtained in spite of low polymerization temperature of $30^{\circ}C$. Under controlled conditions, PMMA/silver microspheres with various number-average degrees of polymerization (6,000-37,000) were prepared. Morphology studies revealed that except for normal suspension microspheres with a smooth surface, a golf ball-like appearance of the microspheres was observed, due to the migration and aggregation of the hydrophilic silver nanoparticles at the sublayer beneath the microsphere's surface.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.622-630
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• 2006

This paper is about the magnetic suspension stage based on the Switched Reluctance propulsion principle. Because the previous studies on contact-free stage adopted the Lorentz force for main force generation mechanism they have suffered from thermal problem deteriorating the precision. Thus, the magnetic suspension stage adopting SR principle which can achieve high force density is proposed. The main operating principle and structure for achieving high resolution and long travel range are represented. The magnetic force analysis of each actuator, providing back data for dynamic modeling and controller design are carried out. By conducting basic experiments, the feasibility of the proposed system is shown. In addition the problems which should be improved and their solutions are represented.

• Journal of Arbitration Studies
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• v.23 no.2
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• pp.81-113
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• 2013

The World Trade Organization (WTO) offers remedies for non-compliance by the introduction of compensation or retaliation in the Dispute Settlement Understanding (DSU). There are no the provisions under the WTO DSU and it seems unclear what retaliation is attempting to achieve. Therefore, it is unclear whether the goal of WTO retaliation is to induce compliance or to restore the balance between the rights and the obligations of WTO members. It has been claimed the WTO has a strong dispute settlement system by providing retaliation when the recommendations and rulings of Dispute Settlement Body (DSB) are not complied with. But this seems to be inadequate to bring about effective and timely compliance. Especially there is a problem with free riding by a violating member because the level of retaliation is determined from the expiration of a reasonable period of time, providing an incentive to delay compliance. Also the level of the suspension of concessions or other obligations authorized by the DSB is equivalent to the level of nullification or impairment, according to DSU Article 22.4. However, if the member concerned objections to the level of the suspension proposed, the matter shall be referred to arbitration. The arbitrator shall not examine the nature of the suspension of concessions or other obligations to be suspended but shall determine whether the level of such suspension is equivalent to the nullification or impairment. The arbitrator makes an assessment standard of equivalence by comparing the suspension of concessions or other obligations and the nullification or impairment calculated in terms of the amount of trade. But it is necessary that other standards replace the quantitative standards when the level of the nullification or impairment cannot be quantified by concrete damages.

• Toxicological Research
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• v.12 no.2
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• pp.295-303
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• 1996

Acute toxic effects of the Woo Whang Chung Shim Won suspension and pills were studied with the doses of 60, 74, 90, and 110 ml/kg in mice. In this study, we daily examined number of deaths, clinical signs, body weights, and pathological findings for 7 days after administration of Woo Whang Chung Shim Won. All mice given the highest dose (110ml/kg) died at 24 hour after administration of Sam-Sung Woo Whang Chung Shim Won suspension (Byunbang, SS-BS and Wonbang, SS-WS), one male and two female mice given 90 ml/kg dose of SS-BS died, and a few mice given middle dose (74 ml/kg) of SS-WS died. In control group (110 ml/kg) treated with vehicle (SS-BS and SS-WS), three out of 5 males and two out of 5 females mice died during the study. However, in animals treated with Kwang-Dong Woo Whang Chung Shim Won suspension (KD-S) and pill (KD-P), deaths were not observed. In the clinical signs, increase of drooling and decrease of spontaneous motor activities were observed in the highest dose group (110 ml/kg). No significant dose-related change in body weight was observed. The results suggest that the toxic effect of SS-BS and SS-WS may be atttributed to the solution for the Woo Whang Chung Shim Won suspension.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.357-362
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• 2011

Air springs are prevalently used as suspension in train. However, air springs are seldom used in automobiles where they improve stability and comfort by enhancing the impact-relief, breaking, and cornering performance. Thus, this study proposed a new method to analyze air springs and obtained some reliable design parameter which can be utilized in vehicle suspension system in contrast to conventional method. Among air spring types of suspension, this study focused on sleeve type of air spring as an analysis model since it has potential for ameliorating the quality of automobiles, specifically in its stability and comfort improvement by decreasing the shock through rubber sleeve. As a methodology, this study used MARC, as a nonlinear finite element analysis program, in order to find out maximum stress and maximum strain depending on reinforcement cord's angle variation in sleeves. The properties were found through uniaxial tension and pure shear test, and they were developed using Ogden Foam which is an input program of MARC. As a result, the internal maximum stresses and deformation according to the changes of cord angle are obtained. Also, the results showed that the Young's modulus becomes smaller, then maximum stresses decrease. It is believed that these studies can be contributed in automobile suspension system.