• Title/Summary/Keyword: OTPA(operational transfer path analysis)

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Analysis of the Cause of Hindrance for Ride Quality with OPAX and OTPA (변수모델을 이용한 전달경로분석법(OPAX)과 전달률 함수를 사용한 전달경로분석법(OTPA)을 사용한 승차감 저해요인분석)

  • Kim, Jongsik;Sin, Kwangsoo;Choi, Sangil;Im, Sebin;Kim, Jindong;Lee, Sangkwon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.12
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    • pp.935-942
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    • 2014
  • 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.

The Research for Higher Ride Quality with OPAX and OTPA (변수모델을 사용한 전달경로분석법(OPAX)과 전달률 함수를 사용한 전달경로분석법(OTPA)을 사용한 승차감 향상 연구)

  • Shin, Kwangsoo;Choi, Sangill;Kim, Jongsik;Lee, Sangkwon;Im, Sebin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.1
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    • pp.65-73
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    • 2015
  • The ride quality has become a key component of not only design but car selling as the technology developed and the requirement of passengers grew up. Thus car industry invests lots of time and cost for the higher ride quality. The evaluation of the ride quality mainly is expressed by subjective element that drivers felt. In this paper, instead of the original transfer path analysis method, relatively new methods such as OPAX(Operational path analysis with eXogeneous inputs) and OTPA(operational transfer path analysis) are used for analyzing the main hindrance element of ride quality. With those new method, contribution rate of all paths that the vibration propagate along analyzed after driving test on the roads having different characteristic. The comprehensive hindrance elements of ride quality are deduced from the contribution rate and the improve experiment by changing one of hindrance elements for higher ride quality.

A Study on Contribution Analysis using Operational Transfer Path Analysis based on the Correlation between Subjective Evaluation and Zwicker's Sound Quality Index for Sound Quality of Forklifts (지게차의 주관적 음질평가와 Zwicker 음질지수의 상관관계 및 전달경로분석법(OTPA)을 활용한 음질 기여도 분석)

  • Kim, Beom Soo;Yang, Soon Yong
    • Journal of Drive and Control
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    • v.13 no.2
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    • pp.19-25
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    • 2016
  • 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.

Contribution Analysis to Identify the Source of Ship Hull Vibration (선체 진동 특성 규명을 위한 기여도 분석)

  • Lee, Jun Woo;Ahn, Se Jin;Oh, Jun Seok;Kim, Tae Hyeong;Jeong, Weui Bong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.5
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    • pp.528-535
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    • 2016
  • 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.

Contribution Analysis of Simulated Pass-by Data using Operational Transfer Path Analysis

  • Lohrmann, Martin;Kluiber, Florian
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2010.05a
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    • pp.123-125
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    • 2010
  • As the exterior noise emitted by a vehicle is getting more and more attention, simulated pass-by measurements become more important. This well established method provides information about the total noise emitted by the vehicle. For a vehicle manufacturer it is not only interesting to know about the total noise but also to know how this total exterior noise is composed of different contributions, such as for example the contribution of the engine, the intake or exhaust system. Transfer path analysis (TPA) provides a separation of these contributions for each of the pass-by microphones alongside the track. Presented is a method for fast and efficient determination of the contributions of multiple sources using operational transfer path analysis (OTPA). The calculation of the transfer characteristics between the reference measurement points on the vehicle and the corresponding response points of both microphone lines are carried out while operation of the vehicle. As result of the contribution analysis from operational transfer path analysis, the characteristic noise level as function of the covered distance is displayed for all individual sound sources, thus providing in depth information for sound quality engineering.

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A Study on Interior Noise Contribution Analysis of Trains based on OTPA Method (OTPA방법을 이용한 철도차량 실내 소음 기여도 분석 연구)

  • Jung, Jae-Deok;Hong, Suk-Yoon;Song, Jee-Hun;Kwon, Hyun-Woung;Noh, Hee-Min;Kim, Jun-Kon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.1
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    • pp.97-103
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    • 2016
  • 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.