Prediction of the Sound Insulation of the Body Structure of High-Speed Trains based on the Hybrid FE-SEA Method

Author(s):  
D. Sansan ◽  
Z. Yanju ◽  
A. Tian ◽  
D. Jian
2017 ◽  
Vol 29 (3) ◽  
pp. 528-535
Author(s):  
Yoichi Masuda ◽  
◽  
Masato Ishikawa

[abstFig src='/00290003/08.jpg' width='230' text='The tripedal robot “Martian petit”' ] Significant efforts to simplify the body structure of multi-legged walking robots have been made over the years. Of these, the Spring-Loaded-Inverted-Pendulum (SLIP) model has been very popular, therefore widely employed in the design of walking robots. In this paper, we develop a SLIP-based tripedal walking robot with a focus on the geometric symmetry of the body structure. The proposed robot possesses a compact, light-weight, and compliant leg modules. These modules are controlled by a distributed control law that consists of decoupled oscillators with only local force feedback. As demonstrated through experiments, the simplified design of the robot makes possible the generation of high-speed dynamic locomotion. Despite the structural simplicity of the proposed model, the generation of several gait-patterns is demonstrated. The proposed minimalistic design approach with radial symmetry simplifies the function of each limb in the three-dimensional gait generation of the robot.


Author(s):  
James K. Hopkins ◽  
Satyandra K. Gupta

In recent years, snake-inspired locomotion has garnered increasing interest in the bio-inspired robotics community. This positive trend is largely due to the unique and highly effective gaits utilized by snakes to traverse various terrains and obstacles. These gaits make use of a snake’s hyper-redundant body structure to adapt to the terrain and maneuver through tight spaces. Snake-inspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous variations of the rectilinear gait were inefficient in cyclic displacement. These gaits generated vertical waves traveling along the length of the robot. Generating these waves required significant joint energy for relatively small horizontal displacements. This paper presents analytical and experimental results for a rectilinear gait, which demonstrates significant linear displacement for relatively low joint effort. The low effort gait functions by propagating a wave through the length of the robot via expansions and contractions of the body segments, propelling the robot platform forward. The low effort rectilinear gait is demonstrated on a robot platform that incorporates high speed linear motion and variable traction through friction. We also report the results of a case study showcasing the practical benefits of the low effort gait.


Author(s):  
H. Farahpour ◽  
D. Younesian ◽  
E. Esmailzadeh

Ride comfort of high-speed trains is studied using Sperling's comfort index. Dynamic model is developed in the frequency domain and the power spectral density (PSD) of the body acceleration is obtained for four classes of tracks. The obtained acceleration PSD is then filtered using Sperling's filter. The effects of the rail roughness and train speed on the comfort indicators are investigated. A parametric study is also carried out to evaluate the effects of the primary and secondary suspension systems on the comfort indicators.


2021 ◽  
Vol 100 (4) ◽  
pp. 318-326
Author(s):  
Evgeniy Yu. Bersenev ◽  
Vladimir I. Dubinin ◽  
Vyacheslav M. Ermakov ◽  
Anna I. Kirpicheva

Introduction. To create a regulatory framework, including harmonized with European normative documents in terms of assessing passengers’ comfort, the standard of the enterprise STO RZD “Services in railway transport was developed. Rules for assessing the level of comfort of passengers on trains.” The objective of the study is to compare the indices of the comfort level of passengers, determined by the values of the accelerations acting on them, with the psychological sensations and physiological changes in the body arising in this case, depending on the rolling stock and the state of the track. Material and methods. The experiment using ECG monitoring devices was carried out in four groups of eleven people, six men and five women aged 30-55 years. Additionally, in each group, a psychological survey of 11 more passengers was carried out. All of them were staff members of the Russian Railways divisions. Results. When traveling on high-speed trains “Lastochka” and “Sapsan,” the respondents more often note drowsiness and an exhausted state’s progression. At the end of the trip, they often emphasize stiffness, discomfort, numbness, and numbness of the leg muscles, probably associated with an extended stay in a forced position in the absence of specific freedom movements. In the “lying” position, a person experiences less fatigue, which, according to the sensations, hardly differs from the conditions of a trip in a “sitting” position during short journeys. Regulatory changes in the cardiovascular system are manifested with the combined influence of uncanceled accelerations (the impact of centrifugal forces) and movement speed changes. Conclusion. Carrying out a questionnaire survey and physiological measurements of the dynamics of heart rate fluctuations on the investigated sections of the routes in combination with the obtained technical data on the nature of mobile rail vehicles’ movement confirm the absence of critical discomfort for passengers when traveling on passenger and high-speed trains. The calculated values of the average and constant comfort levels are consistent and do not require correction of the corresponding scales’ values.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jie Zhang ◽  
Xinbiao Xiao ◽  
Xiaozhen Sheng ◽  
Zhihui Li ◽  
Xuesong Jin

A systematic approach to identify sources of abnormal interior noise occurring in a high-speed train is presented and applied in this paper to resolve a particular noise issue. This approach is developed based on a number of previous dealings with similar noise problems. The particular noise issue occurs in a Chinese high-speed train. It is measured that there is a difference of 7 dB(A) in overall Sound Pressure Level (SPL) between two nominally identical VIP cabins at 250 km/h. The systematic approach is applied to identify the root cause of the 7 dB(A) difference. Well planned measurements are performed in both the VIP cabins. Sound pressure contributions, either in terms of frequency band or in terms of facing area, are analyzed. Order analysis is also carried out. Based on these analyses, it is found that the problematic frequency is the sleeper passing frequency of the train, and an area on the roof contributes the most. In order to determine what causes that area to be the main contributor without disassembling the structure of the roof, measured noise and vibration data for different train speeds are further analyzed. It is then reasoned that roof is the main contributor caused by sound pressure behind the panel. Up to this point, panels of the roof are removed, revealing that a hole of 300 cm2 for running cables is presented behind the red area without proper sound insulation. This study can provide a basis for abnormal interior noise analysis and control of high-speed trains.


2011 ◽  
Vol 66-68 ◽  
pp. 850-854
Author(s):  
Yong Liu ◽  
Ning Ping Cao

High-speed trains are easily got overturned in strong crosswind. This paper aims to analyze the fluid field of high-speed train under different distortion angles by using computational fluid dynamics (CFD), hybrid grid method and finite volume method. The results shows that the vortexes roll by the separated airflow are alternating occur and develop along the body from the top and bottom. It causes a strong affect to the lateral stability of the train.


2017 ◽  
Vol 1 (1) ◽  
pp. 115
Author(s):  
Sudar Kajin

Growth and development of the child have the nature of a thorough and intertwined relationships between components (health, nutrition, and environment). In general, child development can be grouped into three areas, namely cognitive, affective, and psychomotor, whereas biological growth which includes a change in the body structure. Body structure regarding the changes in bone structure, especially the long bones that have an impact on changes in body size, whereas changes in bodily functions is a result of hormonal changes that affect the physiological function .. The purpose of this development are: 1) Describe the product feasibility study التربية الجسمية for grade XI IPA at MAN I Mojokerto 2) Describe the development of learning tools using process skills can improve learning outcomes subjects التربية الجسمية class XI IPA at MAN I Mojokerto From the results of this development can be concluded: 1) results of expert validation and testing, the model approach process skills is fit for use for subjects of Physical Education, Sport and Health, because the products developed are not revised by experts but from the results of questionnaire of students stated that require revision are: (a) Improve the look model or change the learning strategy, and (b) improve the use of resources in implementing the model. 2) Product development learning tools using process skills can improve learning outcomes subjects التربية الجسمية class XI IPA at MAN I Mojokerto. From the class of the test increased learning completeness of Pre and Post Tests Tests are respectively 77.78% increase to 91.67%.


2020 ◽  
Vol 140 (5) ◽  
pp. 349-355
Author(s):  
Hirokazu Kato ◽  
Kenji Sato

2017 ◽  
Vol 54 ◽  
pp. 112-119
Author(s):  
L. M. Khmelnychy

The estimation of the first-born cows of Ukrainian Black-and-White dairy breed by the exterior type in the leading breeding herds of Cherkassy region by the method of linear classification (n = 566) has been carried out. The results of the evaluated animals by the 100-score system indicate that within the group of traits, the average level of assessment is "good with the plus". The animals have been differed by the good development of group features characterizing the dairy type (82.4 score), body condition (83.5 score), limbs (82.8 score), udder (82.7 score) and overall score (82.8 score). The degree of development 18 descriptive traits of the exterior of cows, has been predicted by the method of linear classification, indicates their significant intraherd variability. Animals have the moderate height, deep body and angularity. The rump angle, the angle of hock joint and the teats length, according to the variability of scores in the range of 17.8–22.4%, have an average optimal development. The level of scores for the rear width (5.9 score), attachment of the fore (6.3 score) and the rear parts (6.0 score) of the udder testifies to their good development. The body structure of the cows-firstborn has a sufficient description of the type traits that determine their milk yield. At the present stage of selection and breeding work due to the use of bull-sires different origins and breeding value on the local population livestock with significant genotype diversity, the degree of influence each of the hereditary factors in the overall variability of linear features has a scientific and practical significance. In our studies, the force of influence conditional bloodiness of the Holstein mother's breed in the overall fraction of variability of linear type traits within the exterior complexes and the overall assessment takes a significant percentage - from 24.9 to 31.5 with a high degree of reliability according to Fischer's criterion. Among the descriptive traits, the proportion of influence the conditional bloodiness of mother, which is confirmed by high statistical confidence, ranges from 14.4 to 19.8%, and refers to the traits important for breeding. The level of coefficients of influence the father's breeding value in the total phenotypic variability for some of the linear traits is high and reliable. First of all it concerns group traits of the exterior, the development of which is determined by the pedigree value of father by 37.1–41.8%, and the overall assessment of type – by 46.6%. The coefficients of influence father's breeding value in most of the descriptive traits have high reliability (P < 0,001). The coefficients of the force of influence father, depending on the heredity of Holstein for the linear traits of almost the same level as his pedigree value. Since in this case the organized factor is purebreed Holstein and crossbreed bulls-sires of domestic selection, the positive role of Holstein heredity in improving the exterior type of cows has been traced realistically. The necessity of linear breeding, as an effective method in the system of dairy cattle breeding, has been substantiated by reliable values of the coefficients of the force of influence of father's line on the linear traits of offspring (3.4–29.5%). Despite the significant variability of coefficients of the force of influence on the linear traits, most of them have a high level of reliability within the evaluated body parts important for selection. The effect of cows belonging to the maternal line on the development of features of the body structure is insignificant and unreliable (5.3–9.2%). In the process of breeding aimed at improving cows of dairy herd by the exterior type, the pedigree value of parents has been assessed according to the method of linear classification of their daughters and their belonging to perspective genealogical formations.


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