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101.
一种用于车内结构声源辨识的方法 总被引:1,自引:0,他引:1
结合“声学互易性原理”及车内噪声有限元分析,提出一种车内结构声源辨识的方法。该方法可以摆脱对试验的依赖,因而能够应用于车身结构的图纸设计阶段。然后,采用该方法对某型国产轿车的车内结构声源进行辨况,发现对驾驶员右耳位置处噪声贡献最大的车身结构板块为右前车项,这一结论与采用相关分析法所得结论相一致。最后,基于车内降噪优化模型对右前车顶进行降噪处理,获得了明显的降噪效果。 相似文献
102.
本文介绍了计算机辅助测量汽车通过噪声的方法,利用计算机多媒体技术可全面真实地再现汽车加速过程中的各种信息及其相互关系,为控制汽车加速噪声提供了强有力的技术支持。 相似文献
103.
汽车制动液的发展与选用 总被引:1,自引:0,他引:1
汽车制动液是保证车辆有效制动和行驶安全的专用化学制品。介绍了制动液的基本要求、发展概况、以及制动的性能和选用中应注意的事项。 相似文献
104.
降低汽车噪声的前提条件是准确确定噪声源位置及声强等参数,声场空间变换方法是确定噪声源位置的一种较好方法,阐述了声场空间变换的理论基础及基本原理,给出了应用实例,并对应用效果进行了分析。 相似文献
105.
盘式制动器制动尖叫计算模型的建立 总被引:14,自引:0,他引:14
借助于有限元和模态综合技术,建立了盘式制动器制动尖叫的摩擦耦合模型。通过复特征分析,得到了对应于每阶段动模态的阻尼与频率,模态阻尼值揭示了哪 些模态不稳定并有可能产生尖叫;最后运用耦合模型研究了摩擦系数和子结构模态对制动尖叫的影响。 相似文献
106.
本文说明了对BC131汽车变速器取力孔盖板做阻尼处理后,可降低噪声声功率级3.2dB,本文分三部分:(1) 阻尼结构的减振降噪机理;(2) 实验装置;(3) 声压级及声功率级的测量和计算。 相似文献
107.
Evaluation of added resistance in regular incident waves by computational fluid dynamics motion simulation using an overlapping grid system 总被引:2,自引:0,他引:2
A computational fluid dynamics simulation method called WISDAM-X was developed to evaluate the added resistance of ships in waves. The Reynolds-averaged Navier–Stokes (RANS) equation was solved by the finite-volume method and a MAC-type solution algorithm. An overlapping grid system was employed to implement rigorous wave generation, the interactions of ships with incident waves, and the resultant ship motions. The motion of the ship is simultaneously solved by combining the solution of the motion of the ship with the solution of the flow about the ship. The free surface is captured by treatment by the density-function method. The accuracy of WISDAM-X is examined by a comparison with experimental data from a container carrier hull form, and shows a fairly good agreement with respect to ship motion and added resistance. Simulations were also conducted for a bow-form series of a medium-speed tanker to examine the effectiveness of the WISDAM-X method as a design tool for a hull form with a smaller resistance in waves. It was confirmed that the WISDAM-X method can evaluate the added resistance with sufficient relative accuracy and can be used as a design tool for ships. 相似文献
108.
研究了船舶噪声的主要来源,揭示了297000dwt超大型油船噪声源的分布规律,对实例噪声结果作了对比,并分析了噪声产生的原因及采取的降噪措施。 相似文献
109.
Tin-cheung Chan Kin-che Lam 《Transportation Research Part D: Transport and Environment》2008,13(5):334-339
We investigate how two non-acoustic factors, information bias and riding frequency, can affect the annoyance response of an urban population to noise created by a new railway line. The study shows that information bias is asymmetrical. Respondents receiving only information on positive measures taken by the authority to reduce noise emission are more tolerant of the noise impact, but those receiving only critical views tend to be more annoyed because they feel that not all measures to reduce noise have been employed. Additionally people who use the line frequently are more tolerant to the noise impact than those who do not. Information bias seems to have a temporary masking effect over riding frequency lasting for a few weeks after railway opening. This suggest that whilst free flow of information provided by the authority can help alleviate annoyance response, encouraging the people affected to make use of the new infrastructure may be useful to reduce public resistance and noise annoyance. 相似文献
110.
Objective To analyze the effect of three therapeutic methods to find an optimal approach to the treatment of intracranial bacterial infection by retrospectively reviewing 33 intracranial bacterial infection patients who were admitted from 1995 to 2008 in oar hospital. Methods The treatments by intermittent lumbar puncture,continuous lumbar subarachnoid space drainage, and embedment of Ommaya cyst for continuous drainage from the ventricles were performed in 15 cases, 12 cases, and 6 cases respectively along with intravenous application of full dose of antibiotics. Results Nineteen cases were cured and the best prognosis was from the group of Ommaya cyst embedment and continuous drainage from the ventricles. Conclusion Management goals are prompt recognition of the central nervous system (CNS) infection, rapid identification of causative organisms and initiation of treatment with the optimal management methods for complications. Embedment of Ommaya cyst for continuous drainage from the ventricle is a safe and effective treatment for intracranial bacterial infection. 相似文献