本文選題：工況傳遞路徑分析 + 奇異值分解　； 參考：《山東大學》2017年碩士論文

【摘要】：挖掘機的NVH性能直接影響著駕駛員的身心健康,是挖掘機產(chǎn)品的核心競爭力所在,越來越多地受到工程技術人員的關注。駕駛室噪聲是挖掘機NVH性能的重要指標之一,盡可能多地降低工程噪聲是改善NVH性能的關鍵。因此,對挖掘機駕駛室內(nèi)噪聲進行研究,對于探究噪聲產(chǎn)生原理以及提出有效改進措施,具有一定的理論研究意義與工程應用價值。本文基于工況傳遞路徑分析方法(OTPA),結合"XX型挖掘機噪聲控制"項目這一工程實踐背景,對某型液壓挖掘機駕駛室內(nèi)噪聲的結構聲成分進行研究,并提出改進措施。首先,研究以OTPA原理為理論基礎,推導出系統(tǒng)傳遞函數(shù)和路徑貢獻的計算方法。并且針對該方法存在的不足對其進行改進:(1)通過對比合成信號和實測信號的頻譜圖,確定是否遺漏重要路徑;(2)通過應用奇異值分解技術處理測試數(shù)據(jù),提高OTPA模型計算準確度。其次,通過分析駕駛室內(nèi)噪聲來源及其傳播方式,以發(fā)動機振動激勵為系統(tǒng)輸入,以駕駛室內(nèi)司機右耳耳旁噪聲為輸出,建立從上車架上發(fā)動機4點安裝位置到駕駛室耳旁的OTPA模型。進而設計試驗,選擇1140r/min、1254r/min、1430r/min、1650r/min、1765r/min、1870r/min 轉(zhuǎn)速下的實測數(shù)據(jù)構建 OTPA 模型,得到系統(tǒng)傳遞率函數(shù)和路徑貢獻;選擇950r/min、1545r/min、2100r/min轉(zhuǎn)速下的實測數(shù)據(jù)進行OTPA模型驗證,對比實測輸出信號和合成輸出信號的頻譜圖,發(fā)現(xiàn)OTPA模型準確有效,可用于后續(xù)降噪方案分析。最后,應用改進后的OTPA方法,對測試數(shù)據(jù)進行處理,通過在分析工況下對OTPA模型的傳遞率函數(shù)和路徑噪聲貢獻進行分析,確定待改進的重點傳遞路徑與敏感頻率位置。分析結果顯示,挖掘機發(fā)動機左后位置減振器和系統(tǒng)結構共振點所對應的敏感頻率位置是重點優(yōu)化改進方向。針對結構共振問題,基于模態(tài)分析法,對挖掘機上車架結構進行整改優(yōu)化,并對改進效果進行了驗證。研究表明,將OTPA方法用于液壓挖掘機發(fā)動機振動到駕駛室結構噪聲之間的路徑傳遞研究是可行的,OTPA方法不但可以有效識別噪聲源,還可以定位對系統(tǒng)輸出影響較大的路徑,為解決駕駛室噪聲問題提供了可靠的理論指導。
[Abstract]:The NVH performance of excavator directly affects the physical and mental health of the driver. It is the core competitiveness of excavator products and is paid more and more attention by engineers and technicians. Cab noise is one of the important indexes of excavator NVH performance. Reducing engineering noise as much as possible is the key to improve NVH performance. Therefore, the research on the noise in the cab of excavator has certain theoretical significance and engineering application value for probing into the principle of noise generation and putting forward effective improvement measures. Based on the method of operating mode transfer path analysis and the project background of "XX excavator noise control", this paper studies the structural sound composition of the noise in the cab of a hydraulic excavator, and puts forward some improvement measures. Firstly, based on OTPA principle, the calculation method of system transfer function and path contribution is derived. Aiming at the shortcomings of this method, we improve it. (1) by comparing the spectrum of the synthetic signal and the measured signal, we can determine if the important path is missing. (2) by using singular value decomposition technology to process the test data, we can improve the accuracy of the OTPA model calculation. Secondly, by analyzing the source of the noise in the cab and its transmission mode, the engine vibration excitation is taken as the system input, and the noise near the right ear of the driver in the cab is taken as the output. The OTPA model from the 4 o'clock position of the engine on the upper frame to the ear of the cab is established. And then design the experiment, select the measured data of 1140 r / min 1254 rmin 1430 r / min 1650 r / min 1765 r / min 1870 r / min to build the OTPA model, and get the system transfer rate function and path contribution, and select the measured data at 950 r / min 1545r / min / min 2100r / min to verify the OTPA model. It is found that the OTPA model is accurate and effective and can be used in the analysis of the subsequent noise reduction scheme by comparing the spectrum of the measured output signal with the synthetic output signal. Finally, the improved OTPA method is used to process the test data. By analyzing the transfer rate function and the path noise contribution of the OTPA model, the key transfer path and the sensitive frequency position are determined. The analysis results show that the sensitive frequency position corresponding to the shock absorber of the left rear position of the excavator engine and the common vibration point of the system structure is the key optimization direction. Aiming at the problem of structural resonance, the structure of excavator frame was optimized based on modal analysis method, and the improvement effect was verified. The results show that it is feasible to use OTPA method to study the path transfer between engine vibration and cab structure noise of hydraulic excavator. It can not only effectively identify the noise source, but also locate the path which has a great influence on the system output. It provides reliable theoretical guidance for solving cab noise problem.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU621

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相關碩士學位論文 前1條

1 齊全;基子OTPA方法的挖掘機駕駛室結構噪聲研究[D];山東大學;2017年

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本文編號：1865064