• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.509-513
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• 2013

There are so many types of construction equipment. Excavator is one of typical construction equipment which is working under the tough and severe environments. It's important for engineers to design CE components by the vibration durability point of view. Traditionally, two typical vibration durability methods to verify the durability of components. The first is experimental method which is using the vibration durability test bench. But experimental approach on vibration durability is needed a lot of cost and time. The second is analytical method which is using the vibration durability analysis such as Dirlik, Stainberg, Lalanne and others methodologies. The one of main advantages on vibration durability analysis can reduce the cost and time. We present a vibration durability analysis process and methodology on the guardrail system in excavator.

• Computers and Concrete
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• v.13 no.1
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• pp.71-82
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• 2014

Chloride ion ingress is one of the major problems that affect the durability of concrete structures such as bridge decks, concrete pavements, and other structures exposed to harsh saline environments. Therefore, durability based design of concrete structures in severe condition has gained great significance in recent decades and various mathematical models for estimating the service life of rein-forced concrete have been proposed. In spite of comprehensive researches on the corrosion of rein-forced concrete, there are still various controversial concepts in quantitation of durability parameters such as chloride diffusion coefficient and surface chloride content. Effect of environment conditions on the durability of concrete structures is one of the most important issues. Hence, regional investigations are necessary for durability based design and evaluation of the models. Persian Gulf is one of the most aggressive regions of the world because of elevated temperature and humidity as well as high content of chloride ions in seawater. The aim of this study is evaluation of some parameters of durability of RC structures in marine environment from viewpoint of corrosion initiation. For this purpose, some experiments were carried out on the real RC structures and in laboratory. The result showed that various uncertainties in parameters of durability were existed.

• Advances in concrete construction
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• v.1 no.1
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• pp.45-63
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• 2013

Upon completion of new concrete structures, the achieved construction quality always shows a high scatter and variability, and in severe environments, any weaknesses and deficiencies will soon be revealed whatever durability specifications and materials have been applied. To a certain extent, a probability approach to the durability design can take the high scatter and variability into account. However, numerical solutions alone are not sufficient to ensure the durability and service life of concrete structures in severe environments. In the present paper, the basis for a probability-based durability design is briefly outlined and discussed. As a result, some performance-based durability requirements are specified which are used for quality control and quality assurance during concrete construction. The final documentation of achieved construction quality and compliance with the specified durability are key to any rational approach to more controlled and increased durability. As part of the durability design, a service manual for future condition assessment and preventive maintenance of the structure is also produced. It is such a service manual which helps provide the ultimate basis for achieving a more controlled durability and service life of the given concrete structure in the given environment.

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

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.336-341
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• 2003

In this paper, resonance durability analysis technique is presented for the fatigue life assessment considering dynamic effect of a vehicle system. In the resonance durability analysis, the frequency response and the dynamic load on frequency domain are used. Multi-body dynamic analysis, finite element analysis, and fatigue life prediction method are applied for the virtual durability assessment. To obtain the frequency response and the dynamic load, the computer simulations running over typical pothole and Belgian road are carried out by utilizing vehicle dynamic model. The durability estimations on the rear suspension system of the passenger car are performed by using the presented technique and compared with the quasi-static durability analysis. The study shows that the fatigue life considering resonant frequency of vehicle system can be effectively estimated in early design stage.

• International Journal of Concrete Structures and Materials
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• v.2 no.2
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• pp.137-143
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• 2008

In recent years, much research work has been performed on durability design and long-term performance of concrete structures in marine environments. In particular, the development of new procedures for probability-based durability design has been shown to provide a more realistic basis for the analysis. This approach has been successfully applied to several new concrete structures, where requirements for a more controlled durability and service life have been specified. For reinforced concrete structures in a marine environment, it is commonly assumed that the dominant degradation mechanism is the corrosion of the reinforcement due to the presence of chlorides. The design approach is based on the verification of durability limit states, examples of which are: depassivation of reinforcement, cracking and spalling due to corrosion, and collapse due to cross section loss of reinforcement. With this design approach the probability of failure can be determined as a function of time. In the present paper, a probability-based durability performance analysis is used in order to demonstrate the importance of the durability design approach of concrete structures in marine environments. In addition, the sensitivity of the various durability parameters affecting and controlling the durability of concrete structures in a marine environment is studied. Results show that the potential of this approach to assist durability design decisions making process is great. Based the crucial information generated, it is possible to prolong the service life of structures while simultaneously optimizing the final design solution.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.13-18
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• 2007

The research was performed to review the design factors which affect the durability of structures. For the study, domestic and foreign literature review were performed on various design criteria. Based on Korean standard specifications, the results showed that the durability of structure as the diameter of reinforcing steel bar becomes smaller and the distance between reinforcing bar is closer than the normal gap. The results were also presented that the minimum required bar cover is 6.6cm to obtain the durability index value. In addition, the maximum limited bar cover was 12cm considering the durability index and the change of increasing value of durability index. In case that there is no specified regulation for the bar cover thickness change, the durability life by neutralization is proportional to the thickness of bar cover.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.991-996
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• 2001

The long-term durability characteristics of high-early-strength concrete were assessed. The effect of long-term durability characteristics of high-early-strength concrete were investigated. In experiment, two different types of fiber were adopted for improvement of durability. High-early-strength fiber reinforced concretes using regulated-set cements are compared with high-early-strength concrete without fiber. The durability performance of the laboratory-cured high-early-strength concrete specimens was determined by conducting an accelerated chloride permeability, abrasion resistance, freeze-thaw, surface deicer salt scaling and wet-dry repetition test. The results indicated that incorporation of fibers enhance durability performance.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.286-291
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• 1995

The deterioration of PC box girder may cause serious effect on the durability of PC structure compared to that of RC structures. In the durability assessment of PC box girder bridges, a quantitive model on crack width is considered as a measure of durability. This study suggests a durability limit state model for PC box girder bridges. This durability limit state model in formulated based on the conventional models on the cracks in concrete. And the allowable crack width is taken as an assumed value established by the design specification or provided by the maintenance authority of the structure.

• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.24-31
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• 1995

This paper shows the fatigue durability test method for vehicle suspension systems. Durability should be assured for the safe driving during vehicle life cycle. A computer simulation for the vehicle dynamics was used to obtain dynamic loads that were required for the fatigue durability test. Durability tests were done for an Important load-carrying component of the suspension system. Stress analyses using stresscoat and strain gages were also done for the component. This study demonstrated an effective method for the fatigue durability test.