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지게차의 주관적 음질평가와 Zwicker 음질지수의 상관관계 및 전달경로분석법(OTPA)을 활용한 음질 기여도 분석
김범수(Beom Soo Kim),양순용(Soon Yong Yang) 유공압건설기계학회 2016 드라이브·컨트롤 Vol.13 No.2
Recently, drivers have begun to regard comfort in the cabin as one of the most important factors in construction equipment like forklifts. Accordingly, it has become more important to design a forklift cabin with a better sound quality as well as lower sound level, which can make a driver more comfortable. In this paper, the correlation between subjective evaluation and Zwicker’s sound quality index was analyzed through a blind test by a few workers in forklifts and other construction equipment in several countries. Correlation analysis showed that Loudness and Sharpness were ranked in sequence, and tendencies were different from country to country. Also, contribution analysis for Loudness and Sharpness using operational transfer path analysis (OTPA), which is widely used in the field of noise, vibration, and harshness (NVH), was performed. However, Loudness and Sharpness cannot be used with OTPA directly because there are no linear relationships between the sources and receivers. In this paper, both are calculated by applying the DIN 45631 method with a contribution rate (%) of 1/3 Octave Sound Pressure Level by OTPA method in addition to considering spectral masking.
정재덕(Jae-Deok Jung),고동신(Dong Shin Ko),허덕재(Deog Jae Hur),이원기(Won Gi Lee) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
차량의 전동화로 인해 실내공간이 확장되고 이를 활용하기 위한 차량용 시트의 연구개발이 진행되고 있다. 기존 레일에 비해 3~4배 긴 레일을 설치하여 앞뒤의 이동 자유도를 높일 수 있다. 길어진 레일로 인해 강성이 낮아지고 구동 속도가 증가함에 따라 진동과 소음이 상대적으로 증가하게 된다. 진동 기여도 분석은 OTPA(Operational Transfer Path Analysis)를 사용하여 분석을 진행하였다. OTPA는 PCA와 SVD 과정을 거쳐 구동 중 여러 전달경로에 대한 기여도를 한 번에 도출한다. 또한 전통적인 방법과 달리 소음원 분리에 의한 경계 조건이 변하지 않는 장점을 갖는다. 센서 부착위치는 Photo.1과 같으며 S7위치의 가속도계를 대상(target)으로 설정하였으며 시트가 전진방향으로 구동할 때 각 부위의 기여도를 분석하였다. 시트 소음기여도 분석은 OTPA 분석 절차를 프로그램화 하여 데이터 처리를 수행하였다. S7의 앞뒤방향(x방향)에 대한 각 전달 경로 별 기여도 결과는 Photo.2와 같고 주파수에 따른 전체 진동레벨(overall)을 RMS로 나타내었다. S7의 앞뒤방향에 대한 기여도를 순위별로 나열하면 U2, W3, U1 순으로 나타나 어퍼레일과 스위블의 영향이 가장 지배적인 것으로 나타났다. 특히 어퍼레일의 경우 좌우방향(y방향) 진동에 의한 기여도가 가장 크게 나타났으며 스위블의 경우 위아래방향(z방향)의 기여도가 크게 나타남을 확인하였다.
OTPA방법을 이용한 철도차량 실내 소음 기여도 분석 연구
정재덕(Jae-Deok Jung),홍석윤(Suk-Yoon Hong),송지훈(Jee-Hun Song),권현웅(Hyun-Woung Kwon),노희민(Hee-Min Noh),김준곤(Jun-Kon Kim) 한국소음진동공학회 2016 한국소음진동공학회 논문집 Vol.26 No.1
The sensitivity of interior noise that the passengers perceive is comparatively high in the train, and structure-borne and air-borne types of noises come into the train. In this paper, to analyze contributions of these noise sources operational transfer path analysis(OTPA) is used. OTPA has some advantages of executing the contribution rates of several sources simultaneously, and in this work, 29 points are measured while running. Transfer functions between reference measurement points and response measurement points are calculated by the singular value decomposition(SVD) and Principal component analysis(PCA) method, and the frequency characteristics of the noise source are successfully derived. Also the interior noise is predicted and compared with measurement data to show the reliability.
변수모델을 이용한 전달경로분석법(OPAX)과 전달률 함수를 사용한 전달경로분석법(OTPA)을 사용한 승차감 저해요인분석
김종식(Jongsik Kim),신광수(Kwangsoo Sin),최상일(Sangil Choi),임세빈(Sebin Im),김진동(Jindong Kim),이상권(Sangkwon Lee) 한국소음진동공학회 2014 한국소음진동공학회 논문집 Vol.24 No.12
The ride quality investigation is on-going topic in the car industry since its global standard has not evaluated and it is difficult to point out one part that hinders the ride quality. Since the traditional transfer path analysis that is widely used in car industry to investigate the ride quality requires a lot of test time to process the full data so that there are problems to conduct in industry. Based on these disadvantages, new approaches have developed such as OPAX(operational path analysis with eXogeneous inputs) and OTPA(operational transfer path analysis) for last decades. The OTPA only requires the operational data for evaluate the contribution of vibration sources and the OPAX has advantage of using parametric model to estimate the operating load and needs a minimum set of extra tests with excitation. In this paper, for evaluating the hindrance of ride quality two methods are used and the result is compared with another result of a car having higher ride quality.
이준우(Jun Woo Lee),안세진(Se Jin Ahn),오준석(Jun Seok Oh),김태형(Tae Hyeong Kim),정의봉(Weui Bong Jeong) 한국소음진동공학회 2016 한국소음진동공학회 논문집 Vol.26 No.5
The vibration of a ship gives a significant effect on the noise radiated into the water. This paper focused on the vibration of ship hull due to the sub-generator located on the deck in the anchored condition. The contributions of the transfer paths between sub-generator and ship hull were analyzed using the TPA and the OTPA method. While the sub-generator was operation and the main engine was turned off, the vibrations were measured simultaneously at the 38 locations of the ship and the one hydrophone was arranged to measure the underwater radiated noise at the overside ship. The results of the transfer path by applying TPA and OTPA were compared and discussed. As a result of these methods, the top of stovepipe and valve are contributive. Reinforcing these structures is the most effective to reduce the vibration of ship hull.