采用多体动力学方法进行汽轮机机械振动激励源精确分析,在激励源分析结果的基础上研究低频激励下的机组振动响应,并采用声传递向量(Acoustic Transfer Vector,ATV)方法研究汽轮机组表面与外场辐射的声压传递贡献量,从多体动力学的角度...采用多体动力学方法进行汽轮机机械振动激励源精确分析,在激励源分析结果的基础上研究低频激励下的机组振动响应,并采用声传递向量(Acoustic Transfer Vector,ATV)方法研究汽轮机组表面与外场辐射的声压传递贡献量,从多体动力学的角度并结合流固耦合的方法综合分析汽轮机组振动噪声产生机理并研究噪声典型传递路径。研究结果表明,旋转激励源为汽轮机组的主要振动激励源,在低频段汽轮机组辐射模式为单极子,在中高频段汽轮机组辐射模式为偶极子。由噪声辐射的指向性极坐标图可知,在不同高度处噪声指向性相似,并都在长度方向上取得噪声声压级较大值,具有较强的指向性。计算方法对汽轮机组减振降噪研究具有一定的指导意义。展开更多
轮轨噪声是列车主要噪声源,而车轮振动声辐射是轮轨噪声的重要组成部分。降低车轮振动声辐射是控制轮轨噪声的有效方法之一。通过在车轮辐板位置安装动力吸振器,以吸收主振动系统的能量,达到减振降噪的目的。利用有限元—边界元方法,研...轮轨噪声是列车主要噪声源,而车轮振动声辐射是轮轨噪声的重要组成部分。降低车轮振动声辐射是控制轮轨噪声的有效方法之一。通过在车轮辐板位置安装动力吸振器,以吸收主振动系统的能量,达到减振降噪的目的。利用有限元—边界元方法,研究动力吸振器主要参数,包括质量比、阻尼损耗因子、结构形式、动力吸振器数量对车轮降噪效果的影响。研究表明三自由度动力吸振器加入适当阻尼可降低振动声辐射6 d B(A)。展开更多
The current researches of wheel vibration and sound radiation mainly focus on the low noise damped wheel. Compared with the traditional research, the relationship between the sound and wheel/rail contact is difficulty...The current researches of wheel vibration and sound radiation mainly focus on the low noise damped wheel. Compared with the traditional research, the relationship between the sound and wheel/rail contact is difficulty and worth studying. However, there are few studies on the effect of wheel load on wheel vibration and sound radiation. In this paper, laboratory test carried out in a semi-anechoic room investigates the effect of wheel load on wheel natural frequencies, damping ratios, wheel vibration and its sound radiation, The laboratory test results show that the vibration of the wheel and total sound radiation decrease significantly with the increase of the wheel load from 0 t to 1 t. The sound energy level of the wheel decreases by 3.7 dB. When the wheel load exceeds 1 t. the attenuation trend of the vibration and sound radiation of the wheel becomes slow. And the increase of the wheel load causes the growth of the wheel natural frequencies and the mode damping ratios. Based on the finite element method （FEM） and boundary element method （BEM）, a rolling noise prediction model is developed to calculate the influence of wheel load on the wheel vibration and sound radiation. In the calculation, the used wheel/rail excitation is the measured wheel/rail roughness. The calculated results show that the sound power level of the wheel decreases by about 0.4 dB when the wheel load increases by 0.5 t. The sound radiation of the wheel decreases slowly with wheel load increase, and this conclusion is verified by the field test. This research systematically studies the cffcct of wheel load on wheel vibration and sound radiation, gives the relationship between the sound and wheel/rail contact and analyzes the reasons, therefore, it provides a reference for further research.展开更多
文摘采用多体动力学方法进行汽轮机机械振动激励源精确分析,在激励源分析结果的基础上研究低频激励下的机组振动响应,并采用声传递向量(Acoustic Transfer Vector,ATV)方法研究汽轮机组表面与外场辐射的声压传递贡献量,从多体动力学的角度并结合流固耦合的方法综合分析汽轮机组振动噪声产生机理并研究噪声典型传递路径。研究结果表明,旋转激励源为汽轮机组的主要振动激励源,在低频段汽轮机组辐射模式为单极子,在中高频段汽轮机组辐射模式为偶极子。由噪声辐射的指向性极坐标图可知,在不同高度处噪声指向性相似,并都在长度方向上取得噪声声压级较大值,具有较强的指向性。计算方法对汽轮机组减振降噪研究具有一定的指导意义。
文摘轮轨噪声是列车主要噪声源,而车轮振动声辐射是轮轨噪声的重要组成部分。降低车轮振动声辐射是控制轮轨噪声的有效方法之一。通过在车轮辐板位置安装动力吸振器,以吸收主振动系统的能量,达到减振降噪的目的。利用有限元—边界元方法,研究动力吸振器主要参数,包括质量比、阻尼损耗因子、结构形式、动力吸振器数量对车轮降噪效果的影响。研究表明三自由度动力吸振器加入适当阻尼可降低振动声辐射6 d B(A)。
基金Supported by National Science and Technology Support Program of China(Grant No.2009BAG12A01-B06)National Hi-tech Research and Development Program of China(863 Program,Grant No.2011AA11A103-2-2)+3 种基金Funds for Innovation Research Team of Ministry of Education of China(Grant Nos.IRT1178,SWJTU12ZT01)Fundamental Research Funds for the Central Universities and the Science of China(Grant No.SWJTU12ZT01)2015 Doctoral Innovation Funds of Southwest Jiaotong University of ChinaProject of State Key Laboratory of Traction Power of China(Grant No.2011TPL_T05)
文摘The current researches of wheel vibration and sound radiation mainly focus on the low noise damped wheel. Compared with the traditional research, the relationship between the sound and wheel/rail contact is difficulty and worth studying. However, there are few studies on the effect of wheel load on wheel vibration and sound radiation. In this paper, laboratory test carried out in a semi-anechoic room investigates the effect of wheel load on wheel natural frequencies, damping ratios, wheel vibration and its sound radiation, The laboratory test results show that the vibration of the wheel and total sound radiation decrease significantly with the increase of the wheel load from 0 t to 1 t. The sound energy level of the wheel decreases by 3.7 dB. When the wheel load exceeds 1 t. the attenuation trend of the vibration and sound radiation of the wheel becomes slow. And the increase of the wheel load causes the growth of the wheel natural frequencies and the mode damping ratios. Based on the finite element method （FEM） and boundary element method （BEM）, a rolling noise prediction model is developed to calculate the influence of wheel load on the wheel vibration and sound radiation. In the calculation, the used wheel/rail excitation is the measured wheel/rail roughness. The calculated results show that the sound power level of the wheel decreases by about 0.4 dB when the wheel load increases by 0.5 t. The sound radiation of the wheel decreases slowly with wheel load increase, and this conclusion is verified by the field test. This research systematically studies the cffcct of wheel load on wheel vibration and sound radiation, gives the relationship between the sound and wheel/rail contact and analyzes the reasons, therefore, it provides a reference for further research.
