• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.1
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• pp.48-54
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• 2004

Generally, structural optimization is carried out based on external static loads. All forces have dynamic characteristics in the real world. Mathematical optimization with dynamic loads is extremely difficult in a large-scale problem due to the behaviors in the time domain. In practical applications, it is customary to transform the dynamic loads into static loads by dynamic factors, design codes, and etc. But the optimization results with the unreasonably transformed loads cannot give us good solutions. Recently, a systematic transformation has been proposed as an engineering algorithm. Equivalent static loads are made to generate the same displacement field as the one from dynamic loads at each time step of dynamic analysis. Thus, many load cases are used as the multiple loading conditions which are not costly to include in modem structural optimization. In this research, the proposed algorithm is applied to the optimization of flexible multibody dynamic systems. The equivalent static load is derived from the equations of motion of a flexible multibody dynamic system. A few examples that have been solved before are solved to be compared with the results from the proposed algorithm.

• Journal of Aerospace System Engineering
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• v.17 no.1
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• pp.97-105
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• 2023

For aviation sensor pod, structural integrity should be verified through static structural tests for flight loads induced in various maneuvering conditions of the aircraft. For this, it is necessary to develop a test system for full-scale static load test of sensor pod. Based on test requirements, this paper introduced a test system configuration of the static test and the development of test structure frame, restraints equipment, loading equipment, control, and measurement equipment. In addition, methods and procedures for verifying the developed test system were explained. In conclusion, the static load test and data acquisition were successfully performed. Reliability of the test equipment was also verified in the process.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.283-290
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• 2001

In this study, static Pile load tests and PDA for open-ended steel pipe pile($\phi$ = 609.6 mm, t = 14 mm) penetrated into the gravel layer(GP - GM) was accomplished and axial load distribution was measured. Based on the tests results, the ultimate bearing capacity and axial load bearing mode were examined. Also, the ultimate pile capacity was calculated by APIL $E^{PLUS}$./.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.373-380
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• 2002

In this study, In order to compare the behavior of axail load transfer for S.L. coated piles and uncoated piles installed at a field test site. During static pile load tests, axial load transfer for S.L. coated piles and uncoated piles were measured.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.107-116
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• 2000

Dynamic and static load tests are conducted in four construction sites by using steel pipe piles(SPP) and concrete piles to compare differences of load bearing mechanism. Steel pipe piles are instrumented with electric strain gages and are subject to dynamic load tests during driving. The damage of strain gages attached is checked simultaneously. Static load test is also conducted on the same piles after two to seven days' elapse. Then load-settlement behavior and shaft and/or tip resistances are measured. As a result, the allowable bearing capacity calculated by the Davisson's offset method of CAPWAP analysis shows 2~33% larger than that of static load test. The average value of allowable bearing capacity of static load test is closer to the allowable capacity obtained at the safety factor of 2.5 applied on ultimate bearing capacity than to the one obtained from the Davisson's offset method. The analysis of strain gage readings shows that unit skin friction increases with depth. Furthermore, the friction mobilized around the 1~2m above the pile tip considerably contributes to the total shaft resistance.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.12
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• pp.542-548
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• 2002

We consider an unknown linear time invariant plan with static load disturbance. A saturation function nonlinear element is sued to find th one point information in the frequency domain. We analyze an asymmetric self-oscillation caused by static load disturbance with relay feedback and saturation function feedback. We propose a new method to tune a PID controller using a saturation nonlinear feedback element in the presence of asymmetric oscillation. The proposed method does not require the knowledge of plant d.c. gain with an asymmetric oscillation in the plat output.

• Journal of the Korea Concrete Institute
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• v.11 no.5
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• pp.107-118
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• 1999

10 RC bridge piers have been made on a 1/3.4 scale model, and six piers of them were retrofitted with glassfiber. The have been tested in the quasi-static cyclic load so as to investigate their seismic enhancement before and after retrofitting with glassfibers. The objective of this experimental study is to investigate how to strength the ductility of reinforced concrete bridge piers which have been nonseismically designed and constructed in Korea before 1992. Important test parameters are axial load, load pattern, retrofit type. Glassfiber sheets were used for retrofitting in the plastic hinge region of concrete piers. The nonlinear behavior of bridge columns have been evaluated through their yield and ultimate strength, energy dissipation, displacement ductility and load-deflection characteristics under quasi-static cyclic loads. It can be concluded from the test that concrete piers strengthened with glassfibers have been enhanced for their ductile behavior by approximate 50%.

• Journal of the Korean Society for Railway
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• v.8 no.3
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• pp.210-215
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• 2005

The safety evaluations of railway wheelsets make use of the static fracture toughness obtained in ingot materials. The static fracture toughness of wheelset materials has been extensively studied by experiments, but the dynamic fracture toughness with respect to wheelset materials has not been studied enough yet. It is necessary to evaluate the characteristics of the fracture mechanics depending on each location for a full-scale wheelset for high-speed trains, because the load state for each location of the wheelset while running is different the contact load between the wheel and rail, cyclic stress in the wheel plate, etc. This paper deals with the fracture toughness depend on load rates. The fracture toughness depending on load rate data shows that once the downward curve from quasi-static values was reached, subsequent values showed a slow increase with respect to the impact velocity. This means that dynamic fracture toughness should be considered in the design code of the wheelset material.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.884-891
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• 2002

This report is the result performed the structural analysis and the static and fatigue load test of bogie frame for the purpose of designing and verifying the bogie frame which satisfy the load condition required in the UIC code. This investigation is proposed the efficient draft of the design to satisfy the load condition required in the UIC code. And It is performed the structural analysis to evaluate the static strength and the fatigue life of the patient material and the welded part. Also, This is proposed the efficient draft of the test to satisfy the method of the static and fatigue test required in the UC code. And it is carried out the static and the fatigue load test to verify it. We can designed the bogie frame in compliance with UIC 515-4 and 615-4 code.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.700-705
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• 2003

The object of this study is to ensure the stability of flat freight cars using vibration performance test and static load test of body structures. We examined the flat car though static load test and dynamic characteristics analysis related traveling stability and vibration performance. In the results of static load test of body structures for flat car, all structures satisfied allowable stress of materials. The vibration performance test was satisfied with allowable standards. Although flat car exceed speed a little at some speed interval, it was estimated that the cause was not cars but rail.