• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1024-1030
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• 2007

We studied on the characteristics of many kinds of tank cars carrying hazard materials and performed structural strength evaluation for tank of asphalt tank car using finite element analysis. We analyzed the tank strength according to JIS E 7102(Design Method for Tanks of Tank Cars). It was found that the maximum stress obtained at the area supported by the saddle is much lower than the yield stress and the criteria of JIS E 7102.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.282-283
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• 2014

An active study on UHPC, which has been recently used in high-rise building and bridges, is in progress. However, research on adhesion strength of normal concrete and UHPC is required to be studied due to the lack of information. In this study, experimental research progress for adhesion strength (shear strength of adhesive surface) evaluation of Bi-compressive strength concretes (UHPC, Normal concrete) is proceeded. First, specimens using glue are produced and surface treatment methods of concrete bonded section are considered. Second, Direct Shear test is applied on concrete bonded section of UHPC (80~180MPa) and Normal Concrete (NC). As a result of this study, it is confirmed that bond strength is deteriorated as the difference of intensity ration of NC and UHPC increases.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.3
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• pp.230-234
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• 2009

As concrete ages, the surrounding environment is expected to have growing influences on the concrete. As all the impacts of the environment cannot be considered in the strength-estimating model of a nondestructive concrete test, the increase in concrete age leads to growing uncertainty in the strength-estimating model. Therefore, the variation of the model error increases. It is necessary to include those impacts in the probability model of concrete strength attained from the nondestructive tests so as to build a more accurate reliability model for structural performance evaluation. This paper reviews and categorizes the existing strength-estimating statistical models of nondestructive concrete test, and suggests a new form of the strength-estimating statistical models to properly reflect the model uncertainty due to aging of the concrete. This new form of the statistical models will lay foundation for more accurate structural performance evaluation.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.166-173
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• 1998

The evaluation of joint fatigue strength of light weight materials for an electrical vehicle body has been performed through T-peel joint tests with the design parameters such as joint style, adherend type, adherend thickness, adhesive thickness, and various adhesives. Fatigue strength was evaluated through 5-Hz, tension-tension, load controlled test with the zero stress ratio. It was observed that the fatigue strength of the joint increases with the increase of the adherend thickness. With the increase of the adhesive thickness, however, the fatigue strength of the joint increases insignificantly. An aluminum-FRP adherend combination shows much higher fatigue strength than an aluminum-aluminum adherend combination. The results of fatigue tests were found to be consistent with those of static tests.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.1-9
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• 2016

PURPOSES : This study focuses on the evaluation of interface performance with varying surface texture and tack coat application in an asphalt overlay. METHODS : The evaluation is carried out in two phases: tracking test and interface bond strength test. Using an image processing tool, tracking test is conducted to evaluate the susceptibility of the tack coat material to produce excessive tracking during application. Using the pull-off test method, the bond strength test is performed to determine the ability of the interface layer to resist failure. RESULTS : Results show that the underseal application yields less tracking compared to other applications. However, the bond strength is barely within the minimum acceptable value. On the other hand, RSC-4 produces higher bond strength for all surface types, but the drying time is long, which produces excessive tracking. CONCLUSIONS : While underseal application may be suitable for a trackless condition, the bond strength is less appealing compared to the rest of the tack applications available. RSC-4 demonstrated a high and consistent bond strength performance, but more time is required for drying to avoid excessive tracking. Tack coat application and surface type combination produce varying results. Therefore, these should be considered when selecting suitable future tack coat application options.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.242-249
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• 1999

Spot welding is very important and useful technology in fabrication of an automobile body structure. Because fatigue strength of the spot welding point is however considerably lower than parent metal due to stress concentration at the nugget edge, accurate stress analysis and fatigue stength evaluation of spot welded lap joint are very important to valuate the reliability and durability of automobile body structure and to establish a criterion of long life fatigue design. Many invetigators have studied so far onsystematic fatigue strength evaluation with various methods. It is however necessary to verify their reliability and abailability for practical application to fatigue design of spot welded structure, Thus,in this study, fatigue strength evaluation methods of spot welded lap joint. which are the maximum principal stress method. the fracture and availability with the Weibull probability distribution. From the results, it was found that reliability and availability withe the Weibull probaility distribution. From the results, it was found that reliability and availability of the suggest fatigue strength estimation methods methods were higher than $\Delta$P-$N_f$ relation. However, among them , reliability of the maximum pricipal stress method was the highest.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.4
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• pp.439-444
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• 2007

A damage analysis simulator, which is applicable for evaluating the residual strength of damaged ship, was developed in this paper. For this process, CDM (Continuum Damage Mechanics) approach has been implemented to the simulator by virtue of the numerical technique for evaluation of crack initiation and/or enlargement. A damage calculation program has been linked with a commercial finite element analysis code (NASTRAN) and a ultimate strength evaluation program (LSAP) in order to assess residual strength of damaged ship. As a results of series calculation for the frigate model, giving the quantitative structural damage to the ultimate strength evaluation, a residual strength with damage is predicted to be at least 70 percentage lower than the case of intact condition. It was found that the proposed technique can be used as a design support tool in the field of simulation based ship design.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.136-141
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• 1995

The early evaluation on strength of concrete is useful to achieve on quality control and improvement of properties of concrete. Especially, we could say that the confidence of construction is increased by the increase durability and safety building, due to early evaluation. In this study, was proposed to ultra-sonic pulse method as a early evaluation method for strength of concrete with main parameter, sush as W/C ratio and S/A ratio. The experiment results are summarized to follow as : $\circled1$ The ultra-sonic pulse was decreased as the increase of W/C ratio. $\circled2$ The maximum value for the ultra-sonic pulse velocity and compressive strength was presented in the case of 40% S/A ratio and these value was decreased as the change of S/A ratio over 40% $\circled1$ The relationship of the ultra-sonic pulse velocity and compressive strength on 28days according to the change of W/C and S/A ratio is to be: $F_{28} = -209193R^2 + 384417R - 1763441$(W/C Ratio) $F_{28} = 1726R^2 - 774R - 502 (S/A Ratio)

• Journal of the Society of Naval Architects of Korea
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• v.43 no.4 s.148
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• pp.467-475
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• 2006

Fatigue strength of hull structural steel plate, extracted from longitudinal bulkhead of a 17-year-old ore/oil carrier for renewal, was investigated in air and in artificial seawater condition. The surface of the plate was covered with corrosion pits and they proved to be crack initiation sites by fractography using SEM. From this research, it was found that the evaluation method for fatigue strength of virgin mild steel plates in air and in artificial seawater can also be applied to the evaluation of the fatigue strength of mild steel plates those were long-term exposed to a corrosive environment and their surfaces had been rusted intensively.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.21-29
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• 2009

The connection strength between wall facing and geosynthetics should be evaluated by experimental method in the design of reinforced earth wall. However, the evaluation result of connection strength using the typical design method, FHWA(1996) and NCMA(1997), is excessively because of a safety factors. Therefore, this study is conducted in connection strength test between wall facing and geosynthetics, then the test result is applied to the design case by NCMA, FHWA and Soong & Koener(1997). The results confirmed that the evaluation method by Soong & Koener, which is used ultimate connection strength by connection strength test in allowable connection strength, is satisfied with stable in design.