【作者】 毕晓博；

【导师】 崔根群；

【作者基本信息】 河北工业大学 ， 车辆工程， 2014， 硕士

【摘要】 能源与环境是本世纪全球面临的两大研究主题，噪声已成为环境污染的一个重要方面。随着工程机械愈来愈向着复杂化、大型化和高速化方向发展，其振动和噪声问题显得更加突出，成为影响人们生活质量、危害人体身心健康的重要因素。论文以校企合作研究项目轮式装载机噪声控制关键技术研究为研究背景，开展了轮式装载机室内噪声源及其特征识别的研究工作。声源诊断与贡献度研究是噪声控制的前提。因此，开展此项研究不仅具有较高的理论研究价值，而且可以为降低轮式装载机噪声指明方向，具有重要的工程应用价值。论文通过试验方法测试了某装载机室内噪声、发动机噪声及相关部件的振动状况；探讨了采用独立分量分析、小波变换技术及经验模态分解相融合的技术（EEMD+ICA）识别噪声源的方法，并利用该方法识别了装载机驾驶室内噪声的主要来源及传递路径；采用偏相干分析方法研究了驾驶室内噪声与驾驶室结构振动的相关性；并提出了降低驾驶室内噪声的建议措施。研究结果表明：1.试验用轮式装载司机位置处噪声声压级为87.4dB(A)，满足我国现行国标《中华人民共和国国家标准土方机械噪声限值》第一阶段的限值要求（89dB(A)），但不能满足即将在2015年实施的第二阶段限值要求（86dB(A)）；驾驶室各个侧面交接处和地板上的多个用于操纵机构通过的孔洞是传递噪声的主要路径。2.利用模拟信号的混合和解混过程，验证了独立分量分析与经验模态分解融合技术对混合信号的分离能力，证明了论文所探讨的利用ICA和EEMD相融合的方法识别装载机室内噪声源特征的技术的可行性。3.采用傅里叶变换（FFT）和小波变换（CWT）技术对通过EEMD-ICA得出了一系列独立分量进行分析，结合时频分析的结果和内燃机噪声研究的先验知识，识别了驾驶室内的主要噪声源，并计算了各独立分量的声功率贡献度。4.利用偏相干分析方法分析了室内噪声与驾驶室结构振动的相关性。提出了切断室外噪声向室内传递的路径，提高驾驶室结构的隔声性能和降低地板振动的建议措施。论文针对轮式装载机室内噪声源及其特征识别研究的EEMD+ICA模型可以在较为简单的试验条件下有效识别噪声源特征，为工程机械噪声控制奠定了理论研究基础和技术方法的支持。更多还原

【Abstract】 Energy and the environment are two important issues of this century, Noise is animportant aspect of environmental pollution.When the development of constructionmachinery moves toward complexcity,large-scale and high speed,its noise and vibrationproblems become more and more prominent and have direct adverse impact on the qualityof life and human health. This thesis on the ground of college-enterprise cooperatedproject Research on the key technology of noise control of wheel loader.the thesisconcentrate on analysis noise source in cab of wheel loader and its feature recognition.Asthe noise source diagnosis and study on the contribution rate is the premise of noisecontrol, it is of great theoretical value and important engineering applications to Researchon the wheel loader indoor noise source and character recognition,and it points out thedirection for Reduce the noise of wheel loader.This paper tested the loader cab noise,the noise of the engine and the vibration ofrelated components through test method.To explore the method that combine componentanalysis,wavelet transform and empirical mode decomposition,and identificate the mainsource of loder cab noise and transmission path by this method.using the Partial coherenceanalysis method examined the coherence between the cab noise and cab structurevibration,and proposed measures to reduce the noise in cabin.the results of research isdescribed as follows:1. the noise sound pressure level of Tested wheel loader driver position is87.4dB(A).the number Meet the national standard of "people’s Republic of China national standardof earthmoving machinery noise limit" the first stage limits (89dB (A)), But can not meetthe second stage limits that will be implemented in2015,(86dB (A)).the junction of eachside in the cab and many through holes for the control mechanism on the floor is the mainpath to transmit noise.2. through The analog signal mixing and unmixing process, verified the independentcomponent analysis and empirical mode decomposition fusion technology for mixed signalseparation ability, Proved the feasibility of combination of ICA and EEMD method forinentify the loader cab noise source characteristics.3. introduced the principal of EEMD-ICA and its application in blind source separation of a loader under different conditions,and obtained a series of independentcomponent. Using Fourier transform and wavelet transform technology to each componentfeatures analysis to identify the independent component and corresponding relation ofinternal combustion engine noise.combining time-frequency analysis results and priorknowledge,identify the main noise source of the cab include exhaust noise,cooling fannoise and combustion noise and the contribution of noise was obtained.4. Using partial coherence analysis method to analyze the correlation of indoor noiseand cab structure vibration. the main noise source control measure were put forward such asprevent noise transfer from outdoor to indoor, improve the sound insulation performance ofcab structure, recommend measures to lower the floor vibrationa, etc.Based on the EEMD+ICA modal,effective identification of noise sourcecharacteristics in wheel loader cab could be achieved in relatively simple test condition.atthe same time,this modal was put forward as foundation and technical method support forengineering machinery noise control.更多还原