Control Algorithm of Static Loading Test for Wind Turbine Blades Based on Fuzzy Theory

Zhang Leian,Huang Xuemei,Yuan Guangming 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.4

In the process of full-scale static loading test of wind turbine blades, the loading forces all had relatively strong coupling effect, which seriously affected the accuracy of the test result. In order to eliminate this effect, firstly, a vertical static loading device for 10MW wind turbine blades was established and the coupling rule of loading force was obtained. Then, a control algorithm was put forward based on fuzzy theory. This algorithm took the error of loading force, error’s change rate as the input variables and the opening degree of proportional valve as the output variable. A control strategy based on this algorithm was constructed. In the end, the static device took the max flapwise of aeroblade5.0-62 wind turbine blade as example to conduct loading test. The result suggested the algorithm in this paper could ensure that the loading forces on five nodes always kept uniform changing and the control errors were respectively less than±2KN, ±2KN,± 2KN,± 2KN and±1KN. When in the 100% phase, the loading force could be finely maintained at the set value. The statistical results showed that the error rates of loading force with control algorithm were smaller than those without control algorithm. The test results verified the feasibility of control strategy applying to full-scale static loading test for wind turbine blades.

우주발사체용 복합재 산화제탱크 구조 강건성 검증을 위한 정하중 시험

김현기,김성찬 항공우주시스템공학회 2021 항공우주시스템공학회지 Vol.15 No.5

This study presented the results of the static load tests conducted to verify the structural robustness of the composite oxidant tank for a space launch vehicle. First, we introduced the test equipment used in the static load test of the composite oxidant tank, and then described the test requirements that the composite oxidant tank must satisfy. In addition, we presented a test set-up diagram consisting of the static load test fixture, hydraulic pressure, control equipment, and data acquisition equipment, and the load profile of the static load test of the composite oxidant tank consisting of shear, equivalent compression, bending, and combination tests. As a result of load control, we verified the reliability of this test by showing the errors between the input load and the feedback load in each channel according to the increase of the test load, and the feedback error between the channel A and channel B of load cell in each load actuator. As a result of the static load test, the load of the actuator was properly controlled within the allowable error range in each test, and we found that the test specimen did not cause damage or buckling that causes significant structural defects in the required load. 본 연구에서는 우주발사체용 복합재 산화제탱크의 구조 강건성을 검증하기 위해 수행된 정하중시험 결과를 제시하였다. 먼저, 복합재 산화제탱크 정하중시험에 사용된 시험장비를 소개하고, 복합재 산화제탱크가 만족해야 하는 시험 요구도를 설명하였다. 그리고, 정하중 시험치구, 유압, 제어장비, 데이터획득장비로 구성되는 시험셋업 구성도를 제시하였고, 전단, 등가압축, 굽힘, 조합시험으로 구성된 복합재 산화제탱크 정하중 시험의 하중 프로파일을 제시하였다. 하중 제어의 결과로 시험하중 증가에 따른 각 하중부과기에서 입력하중과 출력하중 사이의 오차와 각 로드셀 A와 b 채널사이의 오차를 제시하여 본 시험의 신뢰성을 확인하였다. 정하중 시험 결과로, 각 시험에서 하중부과기의 하중은 허용 오차 범위 내에서 적절히 잘 제어되었으며, 시험시편도 요구 하중 내에서 파손이나 심각한 구조적 결함을 유발하는 좌굴은 발생하지 않는 것으로 확인되었다.

Evaluating the Accuracy of Load Application for Static Structural Testing of Aerospace Flight Vehicles

심재열 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.1

This study introduces a method to evaluate the accuracy of load application in static structural tests of aerospace flight vehicles which use lots of actuators. Test data were collected for this study from typical test conditions of four independent structural tests performed within two decades in this laboratory. The tests included three full-scale aircraft tests and a launch vehicle sub-component test. The accuracy of load application was evaluated by calculating the root mean square deviation (RMSD) of errors normalized by DLL (design limit load). The RMSD range of the normalized error for the three full-scale aircraft tests was 0.27–0.89% and was much larger than the 0.04% obtained for the launch vehicle sub-component test. After analyzing the errors in all 91 loading channels used for the four tests, it was determined that tight adjustment of the load limit valve (LLV), and using actuators with a small load ratio, introduced large errors in load application. Even after excluding undesirable data related to the tight adjustment of the LLV and the use of actuators with less than 3% load ratio, the accuracy of load application for the three full-scale tests was still lower than the results for the sub-component test. The factors which induced the large errors in the full-scale tests were determined to be the large displacement of wing or canard and the use of actuators with small load ratio. RMSDs recalculated after excluding the undesirable data were in the range of 0.26–0.41% for the full-scale tests. The maximum value, 0.41%, can be used as tolerance to confirm the accuracy of load application for the next full-scale tests.

현장재하시험을 통한 강관 매입말뚝의 지지력 안전율 제안

박종전,정상섬,박정식 한국지반공학회 2018 한국지반공학회논문집 Vol.34 No.5

In this study, the static and dynamic load tests were carried out to propose the safety factor of steel prebored and precast piles in weathered rocks. The axial load tests have been conducted on test piles with nominal diameters of 0.508 and 0.457 m. The piles were subject to static loading tests (14 times) and dynamic loading tests (EOID 14times, Restrike 14times). The dynamic loading tests were first executed after the casting of test piles (① initial EOID test). ②In the succeding 28 days from completion of construction, static load tests were performed and ③final restrike tests were carried out after 15 days from the static test. As a result, the bearing capacity based on Davisson method was 15% higher than that of the restrike tests. The bearing capacity of the static load tests were larger than that of the dynamic tests. By comparing the safety factor through various loading tests, the safety factor of dynamic loading tests were suggested to be lowered to 1.75 from the conventional 2.0.

KC-100 전기체 정적 구조시험

심재열(Jae-yeul Shim),정근완(Keunwan Jung),이한용(Hanyong Lee),이상근(Sang keun Lee),황귀철(Gui-Chul Hwang),안석민(Seokmin Ahn) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.1

항우연에서는 복합재 소형항공기(KC-100)에 대하여 15가지 전기체 시험조건과 7개의 국부적 시험조건들에 대한 전기체 정적구조시험을 수행하였다. 시험요구도, 시험일정, 시험체 및 더미구조, 시험하중산출, 시험장치, 시험장비 등을 소개하였다. 수십개의 제어채널을 사용하는 전기체 구조시험의 하중제어의 정확도를 살펴보기 위하여 U1의 시험데이터를 분석하였다. 분석결과 각 채널별 데이터 획득된 하중값은 허용오차인 SNPE(Static null pacing error)값 이내에서 잘 유지하고 있음을 보였고 본 논문의 저자가 제안한 시험의 하중제어오차 크기 정의방법을 적용한 결과 U1 시험의 하중제어 오차값이 8.6N 이었고 나머지 전기체 시험조건들에 대한 시험데이터를 분석한 결과도 보였다. 마지막으로 U1시험에서 자세제어장치에서 측정된 반력들이 시험하중 증가와 함께 변하는 것을 보였고 전기체 구조시험에서 반력변화 발생의 요인들에 대하여 기술하였다. A full-scale static test for a composite structure small aircraft (KC-100) was conducted in the KARI. The test includes 15 full-scale test and 7 local test conditions. Test requirements with test schedule, test article with dummy structures, test load generation, test system, and equipment are introduced for the test. Test load data of the 1st test condition(U1) was analyzed to evaluate an accuracy of load control for the test. The analysis results show that load data obtained during test were within tolerance of Static Null Pacing Error(SNPE) and the error value of load control was 8.6N. The error of load controls for the full-scale static test using dozens of actuators was calculated by a method suggested by authors. Test data for all other test conditions is also shown in this paper. Finally, reactions measured from restraint system of the U1 test condition show that the reaction changes as load increment. The factors which may change the change of reactions for a full-scale static test are introduced in this study.

Load-Carrying Performance and Hydrostatic Tests of Encapsulated Anchor Systems for Unbonded Post-Tensioning Single-Strands

Ah Sir Cho,Thomas H.-K. Kang 한국콘크리트학회 2018 International Journal of Concrete Structures and M Vol.12 No.2

ACI 318-14 and 423.7-14 require the use of encapsulation system for an unbonded single-strand tendon for the purpose of corrosion protection and enhanced durability. In this study, load-carrying performance and hydrostatic tests were conducted for a newly developed, unbonded post-tensioning (PT) anchor with encapsulation, following the guidelines put forth in KCI-PS101 and ACI 423.7-14. The static load and fatigue tests as part of this study were used to evaluate the anchorage system behavior under static and cyclic loads, respectively. The hydrostatic test was used to demonstrate that the encapsulation system withstood at least 9.3 kPa of water pressure in a 24 h period according to ACI 423.7-14, and thus has been proven to promote the durability of unbonded PT single-strand tendons. Additionally, the push-in and jacking tests were used to assess the compressive and tensile strengths of the anchor as used in the field. Although these tests were not performed to failure for safety reasons, the anchor endured at least 1.18 and 1.02 times the nominal ultimate strength of a strand in each test, respectively. The authors’ previous load transfer tests were also reported in this paper, showing that test specimens with only two horizontal backup bars were capable of resisting at least 1.7 times the nominal ultimate strength of a strand. Based on the favorable results from the loadcarrying performance and hydrostatic tests, the developed encapsulated anchor systems are being applied in actual practice as an economically feasible option in Korean PT industry and are expected to improve the corrosion resistance and durability of posttensioned structures.

Full-scale static test of small composite aircraft

Shim, Jae-Yeul,Ahn, Seokmin The Korean Society for Composite Materials 2014 Advanced composite materials Vol.23 No.1

This paper addresses the accuracy of test load application and reaction prediction of aircraft full-scale static test. Factors which have an effect on the accuracy of load application have been identified. An effective procedure for installing test article and actuators is proposed to achieve accurate loading direction compared to conventional one. A method to define quality of load control for a full-scale static test is suggested by using root mean square deviation (RMSD) of command-feedback (CMF) values. Test result of U1 test condition for the KC-100 full-scale static test has shown 8.7 N of averaged RMSD value. At the end, an approach to make general equation for reaction to load increment has been presented and reaction can be assumed to have relation of linear to load increment for symmetric load condition. The linear behavior has been shown through a test data of the KC-100 aircraft which has high stiffness of composite material structure. The test result presents that the linear behavior of the reaction has been well corresponding to the linear model.

의사정적재하시험을 이용한 PSC 거더교의 공용 내하력평가

윤상귀,신수봉 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 논문집 Vol.23 No.4

In this study, a method for updating the finite element model of bridges with genetic algorithm using static displacement were presented,and verified this method using field test data for PSC girder bridge. As a field test, static load test and pseudo-static load test were conducted, andupdated the finite element model of test bridge using each test data. Finally, evaluated the bridge load carrying capacity with updated model usingpseudo-static load test’s displacement data. To evaluate the bridge load carrying capacity, KHBDC-LSD, KHBDC and AASHTO LRFD’s live loadmodel were used, and compared the each results. 이 연구에서는 정적 변위를 사용하는 유전자 알고리즘을 이용한 교량의 유한요소해석모델 개선 기법을 제안하며, PSC 거더교를 대상으로 한 실증시험 데이터를 이용하여 제안된 방법을 검증하였다. 실증 재하시험으로 정적재하시험과 의사정적재하시험을 수행하였으며, 각 재하시험의 계측 데이터를 이용하여 대상교량의 유한요소해석모델 개선을 진행하였다. 최종적으로 의사정적재하시험의 계측 데이터를 통해 개선된 모델을 이용하여 공용 내하력평가를 수행하였다. 내하력평가에는 현 도로교설계기준과 구 도로교설계기준, AASHTO LRFD의 설계 활하중을 이용하였으며, 각 설계기준 별 내하력평가 결과를 비교하였다.

H-pile의 지지력 특성 및 동역학적 공식의 신뢰도 평가

오세욱,이준대 한국산업안전학회 2003 한국안전학회지 Vol.18 No.1

Recently, pile foundations were constructed in rough or soft ground than ground of well condition thus it is important that prediction of ultimate bearing capacity and calculation of proper safety factor applied pile foundation design. This study were performed to dynamic loading tests for the thirty two piles at four different construction sites and selected pile at three site were performed to static loading tests and then compare with measured value and value of static and dynamic loading tests. The load-settlement curve from the dynamic loading tests by CAPWAP was very similar to the results obtained from the static load tests. Based on dynamic and static loading tests, the reliability of pile-driving formula were analyzed and then suggested with proper safety factor for prediction of allowable bearing capacity in this paper.

고속철도교량의 상시재하시험 타당성 분석에 관한 연구

배석복,박순응,정찬묵 한국철도학회 2020 한국철도학회논문집 Vol.23 No.6

For the safety assessment of a bridge, detailed guidelines for safety and maintenance of the facility are based on field load tests that calculate the response correction factor from the static and dynamic response ratios. The actual deflection of the static response ratio uses the measured value of the static or pseudo-static test; the actual impact factor applies the maximum impact factor value for each load case by speed of the dynamic load test. However, because highspeed railway bridges have a fixed size load compared to road bridges, it is deemed efficient to utilize the measurement of a regular train (safety inspection train) that operates at 170 km/h per day instead of the static load test when calculating the static response ratio. Therefore, to compare the measured values of static and 170 km/h regular operation trains and to ensure their reliability, structural analysis and field load tests were conducted on a PSC Box Girder Bridge, RPF Composite Bridge, and Steel Box Bridge, which are representative superstructure types of high-speed railway bridges.