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一种改进特征模态分解的滚动轴承复合故障特征提取方法
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作者 周小龙 李佳宏 +3 位作者 王相坤 王昊天 杨知伦 曹霖霖 《制造技术与机床》 北大核心 2024年第5期42-49,共8页
针对滚动轴承故障信号非平稳、多分量并伴随强背景噪声,导致其复合故障特征难以有效分离的问题,提出一种改进特征模态分解(feature mode decomposition,FMD)的特征提取方法。采用FMD将滚动轴承复合故障信号分解为一系列模态分量,对影响... 针对滚动轴承故障信号非平稳、多分量并伴随强背景噪声,导致其复合故障特征难以有效分离的问题,提出一种改进特征模态分解(feature mode decomposition,FMD)的特征提取方法。采用FMD将滚动轴承复合故障信号分解为一系列模态分量,对影响分解精度的关键参数特性进行研究,提出了相关参数选取方法。从信号间关联程度和能量角度出发,通过综合评价因子算法选择对故障敏感的模态分量,并经包络解调获取敏感模态分量的包络谱以提取故障特征频率,实现滚动轴承复合故障的诊断。通过仿真信号及实测信号分析,并同变分模态分解(variational mode decomposition,VMD)方法进行比较。结果表明,所提方法可有效抑制噪声干扰影响,提升滚动轴承故障特征信息获取能力,实现滚动轴承复合故障的有效诊断。 展开更多
关键词 特征模态分解 敏感模态分量 滚动轴承 复合故障 特征提取
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Sensitivity Analysis of a Simplified Fire Dynamic Model
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作者 Lars Schiott Sorensen Anker Nielsen 《Journal of Civil Engineering and Architecture》 2015年第6期652-664,共13页
This paper discusses a method for performing a sensitivity analysis of parameters used in a simplified fire model for temperature estimates in the upper smoke layer during a fire. The results from the sensitivity anal... This paper discusses a method for performing a sensitivity analysis of parameters used in a simplified fire model for temperature estimates in the upper smoke layer during a fire. The results from the sensitivity analysis can be used when individual parameters affecting fire safety are assessed. If the variation of a single parameter is found to have a major impact on fire safety, it may be necessary to conservatively select this parameter in order to incorporate additional safety. We compare fire scenarios in rooms surrounded by lightweight as well as heavy walls in order to investigate which parameters are the most significant in each case. We apply the Sobol method, which is a quantitative method that gives the percentage of the total output variance that each parameter accounts for. The most important parameter is found to be the energy release rate that explains 92% of the uncertainty in the calculated results for the period before thermal penetration (te) has occurred. The analysis is also done for all combinations of two parameters in order to find the combination with the largest effect. The Sobol total for pairs had the highest value for the combination of energy release rate and area of opening, which explains 96% of the uncertainty. After thermal penetration, the energy release rate is still the most important parameter, but now only explains 49% of the variation. The second parameter is the thickness of the surface material, which explains 43%. 展开更多
关键词 Sensitivity analysis fire model heavy walls lightweight walls fire-room geometry
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