• Structural Engineering and Mechanics
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• v.19 no.3
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• pp.347-359
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• 2005

This paper attempts to develop the analytical model of estimating the fatigue damage using a linear elastic fracture mechanics method. The stress history on a welding member, when a truck passed over a bridge, was defined as a block loading and the crack closure theory was used. These theories explain the influence of a load on a structure. This study undertook an analysis of the stress range frequency considering both dead load stress and crack opening stress. A probability method applied to stress range frequency distribution and the probability distribution parameters of it was obtained by Maximum likelihood Method and Determinant. Monte Carlo Simulation which generates a probability variants (stress range) output failure block loadings. The probability distribution of failure block loadings was acquired by Maximum likelihood Method and Determinant. This can calculate the fatigue reliability preventing the fatigue failure of a welding member. The failure block loading divided by the average daily truck traffic is a predictive remaining life by a day. Fatigue reliability analysis was carried out for the welding member of the bottom flange of a cross beam and the vertical stiffener of a steel box bridge by the proposed model. Results showed that the primary factor effecting failure time was crack opening stress. It was important to decide the crack opening stress for using the proposed model. Also according to the 50% reliability and 90%, 99.9% failure times were indicated.

• Journal of the Korea Safety Management & Science
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• v.25 no.2
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• pp.85-90
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• 2023

The delivery truck is traveled around the delivery area for a long time. Truck drivers cause traffic accidents because of long hours of driving, fatigue, and speeding, etc. In this study, we will test the factors for preventing accidents of drivers. We would like to find factors that affect accidents and improve that can prevent accidents. As in the results of the study, accidents occur when traffic increases and profits increase among driver age, career, and profit factors. In addition, if the volume of traffic increases during the season, the number of accidents increases further. Therefore, in order to prevent truck accidents, a stable cargo quantity must be allocated to truck and cargo must be delivered.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1309-1315
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• 2011

The design process for obtaining the reliable steeraxle casting beam of fork lift truck is studied in this paper, as the casting beam is major component of steeraxle which has a steering function at driving. In this study, the driving mode and damage pattern of casting beam which could be occurred from the customer site were analyzed and it established the design process to predict the fatigue life by FEA(Finite Element Analysis) so that the reliability of steeraxle casting beam could be verified at DVT(Design Validation Test) mode. This paper provides guidance on the process of designing the reliable steeraxle casting beam at the initial design stage and also, provides guidance on the process of solving the problem when the failure is occurred in the field.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.1-12
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• 2007

A method for assessing fatigue vulnerability of steel bridge members considering corrosion and truck traffic variation with time is proposed to evaluate the reduction of fatigue strength in steel bridge members. A fatigue limit state function including corrosion and traffic variation effect is established. The interaction between the average corrosion depth and the fatigue strength reduction factor is applied to the limit state function as the reduction term of strength. Three types of truck traffic change is modeled for representing real traffic change trend. Monte-Carlo simulation method is used for reliability analysis which provides the data to obtain fatigue vulnerability curves. The estimation method proposed was verified by comparing with the results of reference study and applying to the steel bridges in service.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.652-653
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• 2011

• Steel and Composite Structures
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• v.2 no.6
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• pp.429-440
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• 2002

A finite strip method is developed for fatigue reliability analysis of steel highway bridges. Flat shell strips are employed to model concrete slab and steel girders, while a connection strip is formed using penalty function method to take into account eccentricity of girder top flange. At each sampling point with given slab thickness and modulus ratio, a finite strip analysis of the bridge under fatigue truck is performed to calculate stress ranges at fatigue-prone detail, and fatigue failure probability is evaluated following the AASHTO approach or the LEFM approach. After the failure probability is integrated over all sampling points, fatigue reliability of the bridge is determined.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1047-1053
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• 2022

The leaf spring for a truck absorbs shocks or vibrations from the road surface while driving with the elastic force of the material and prevents the shock from being transmitted to the vehicle body. It is subjected to cyclic stress, and fatigue fracture occurs frequently. This study analyzes fractured leaf spring from a 25 ton truck that has been operating for about a year. In the fractured portion, which is the origin of crack, inclusions were observed, and fatigue failure was caused by cyclic stress. In the stress calculation and FE analysis, the stress at the center of the leaf spring was obtained to be 54~65% of the yield strength of the base material and damaged material. It is most important to prevent the mixing of impurities in the steel manufacturing for leaf springs. The large stress portion of the leaf spring needs to introduce compressive residual stress by peening etc.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.475-487
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• 2003

This study developed an analysis model of estimating fatigue damage using the linear elastic fracture mechanics method. Stress history occurring to an element when a truck passed over a bridge was defined as block loading and crack closure theory explaining load interaction effect was applied. Stress range frequency analysis considering dead load stress and crack opening was done. Probability of stress range frequency distribution was applied and the probability distribution parameters were estimated. The Monte Carlo simulation of generating the probability various of distribution was performed. The probability distribution of failure block numbers was obtained. With this the fatigue reliability of an element not occurring in failure could be calculated. The failure block number divided by average daily truck traffic remains the life of a day. Fatigue reliability analysis model was carried out for the welding member of cross beam flange and vertical stiffener of steel box bridge using the proposed model. Consequently, a 3.8% difference was observed between the remaining life in the peak analysis method and in the proposed analysis model. The proposed analysis model considered crack closure phase and crack retard.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.201-208
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• 2004

To substitute conventional reinforced-concrete bridge deck, glass composite precast bridge deck - Delta Deck/sup TM/, which possesses advantages of light weight, high strength, corrosion resistance and durability, is developed for the DB24 truck load. Pultruded composite bridge deck is designed and fabricated. To verify serviceability and structural safety, finite element analysis, structural testing such as flexural test, local fatigue test, flexural fatigue test and field tests are conducted. In this paper structural characteristics of developed deck and its field application in Korea is presented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.403-410
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• 2004

In the conventional reinforced-concrete bridge deck, concrete and steels are likely to be deteriorated and corroded under the influence of noxious environment. To cope with these problems caused in the conventional reinforced-concrete bridge deck, pultruded composite bridge deck, called Delta Deck, is developed. In this paper, local deflection and fatigue characteristics of Delta Deck for DB24 truck load are evaluated through analysis and experiments.