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Analytical simulation of dynamic characteristics of seat system with nonlinear suspension considering friction effects

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第6期11卷 185-200页

作者： Leilei Zhao Yuewei Yu Changcheng Zhou Xiaohan Li Dehui Huang School of Transportation and Vehicle Engineering Shandong University of Technology 12 Zhangzhou road Zibo 255049P.R.China FAW Jiefang Qingdao Auto Co. Ltd.Qingdao 266043P.R.China

The friction inevitably exists in the nonlinear suspension system for seats.It affects dynamic characteristics of the seat with the nonlinear suspension system.Analysis of the influences of the friction on the seat vibration responses is helpful to improve comfort.Moreover,it is also an important part of promoting the industrialization application of the nonlinear suspension system for seats.In order to verify the influences,a model of the seat with the nonlinear suspension system considering friction effects was established by combining experiments.Based on the model,by using the harmonic balance method,the analytical formulas of the seat frequency-domain vibration response considering friction effects were deduced,and the influences of the friction on the frequency response characteristics of the system were simulated and analyzed.Moreover,the influences of the friction on the time-domain response characteristics were investigated.The results show that the existence of the friction can help to reduce the vibration in the peak region and to increase the system stability,however,it is not conducive to the improvement of the seat comfort under random road conditions.

关键词： seat comfort vibration friction

Factors behind not using child restrain(t) among hospital employees and general population：A case control study

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World Journal of Emergency Medicine 2017年第4期8卷 269-275页

作者： Emad Siddiqui Badar Afzal Ghazala Kazi Asher Feroz Rubaba Naeem Tarab Mansoor Ahreen Allana Saif Siddiqui Zain Siddiqui Department of Emergency Medicine Aga Khan University Hospital Karachi Pakistan

BACKGROUND: Motor vehicle crash(MVC) related injury has been identified as a major public health concern. Child restrain(CR) seat belts can minimize the mortality and morbidity from MVC. The use for seat belts is substantially low in developing countries like Pakistan even though its use has been shown to decrease morbidity and mortality by a significant extent.METHODS: This was a case control study with cases from the general population(GP) and controls from the Aga Khan University(AKU) employees in a 3:1 ratio. The study questionnaire was based on parameters like gender, education level, awareness and presence of CR and also assessed the frequency of usage, reasons for not using CR and the source of knowledge regarding CR use.RESULTS: Out of 848 respondents, 212 were from AKU and 636 were from the GP. 96.7% from AKU had at least a bachelor's degree while less than half(42.6%) of those from the GP were graduate or above(Pseat belts.

关键词： Child restrain seat belt Injury Pakistan

Comparative numerical study on the child head injury under different child safety seat angles

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Theoretical & Applied Mechanics Letters 2019年第4期9卷 260-263,I0005页

作者： Reza Razaghi Hasan Biglari Mojtaba Hasani Alireza Karimi Department of Mechanical Engineering University of TabrizTabrizIran Basir Eye Health Research Center TehranIran Department of Biomedical Engineering Faculty of EngineeringUniversity of IsfahanIsfahanIran Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan

It has been shown that annually around 1250 children younger than 15 years old die in traffic accident.The number of children who also injured as a consequence of car accidents is noticeably higher.According to the ECE-R44 regulation the safety of children in the cars,the use of a child safety seat(CSS)is highly recommended.Using a CSS would dramatically diminish the injuries of traffic accidents.However,the posture,especially the angle,of a child when seating on a seat may also affect the amount of injury occurs during the accident.It has been revealed that during the accident only few children remained seated in the standard position,and most of them whether slouched or slanted and turned their head to the side-support of the CSS.Extreme positions,such as leaning forward,escaping from the harness or holding feet were also observed.This study aimed to perform a finite element(FE)study to figure out what angle of seating would result in the least amount of injury to the child head in a typical car crash under the speed of 47 km/h.To do that,a 1.5 years old child dummy(a dummy representing the anthropometry of a 1.5 years old child)has been accommodated on a seat under the angles of 15°,30°,and 45°.The results revealed.The resulted displacements in the head after the accident were also calculated at X,Y,and Z directions.The results in this regard indicated a higher displacement at X direction whereas the lowest one was seen at Y direction.The results have implications not only for understanding the amount of injury to the child head after the accident under different seating angles,but also for giving an insight to the CSS industries and families to choose the right seating posture for the child in the car to reduce the severity of injury.

关键词： Child Head injury Child safety seat Accident Finite element

THE VIBRATION CHARACTERISTICS OF THE seat OF HOMEMADE J80 SKIDDER

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Journal of Northeast Forestry University 1994年第4期5卷 64-67页

作者：宋驰王以琨宋克非 Northeast Forestry University China Forestry Bureau of Heilongjiang Province China

The test and analysis on the chair system of homemade J80 skidder was carried out. on the basis of the study result, the important parameters, the spring rigidity and the damping coefficient of J80 skidder chair, were... 详细信息

关键词： skidder seat Vibration characteristics Ergonomics

Engine valve and seat insert wear study with a simulator

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Science China Mathematics 2001年第S1期44卷 235-241页

作者： Y.S.Wang S.Narasimhan Eaton Corp. Engine Components Operations 19218 B Drive SouthMarshall MI 49068

The demands on higher performance and the increasing use of alternative fuels chal-lenge engine valves now with greater wear problems than before. A seat wear simulator was builtto evaluate the compatibility and wear of valve and seat insert. The rig test results have been suc-cessfully correlated with engine test results. In this study, intake valves made from Sil 1 materialwere treated with salt bath nitride processes and tested against six different insert materials. Wearresistance of these combinations was ranked and compared to the Sil 1 valve without nitriding.The test results demonstrate that nitriding improved valve seat wear resistance. In the total valveseat recession ranking, the combination of nitrided Sil 1 valve against T 400 insert exhibited theleast total recession among the nineteen combinations of valve and insert tested. The results indi-cate that the valve seat wear mechanisms are a complex combination of adhesion and shearstrain. The nitrides in the compound layer of nitrided valves gave strong atomic bonding, higherhardness, compressive residual stresses, and possible low friction, thus resulted in the superiorwear performance.

关键词： engine valve nitride seat insert valve scat wear mechanism wear simulation

Reliability Research Reviewed of Automobile seat Angle-Adjuster

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World Journal of Engineering and Technology 2017年第1期5卷 1-11页

作者： Lei Liu School of Automotive Engineering Shanghai University of Engineering Science Shanghai China

The reliability of the automobile seat angle-adjuster directly affects the safety of vehicle. The reliability of the seat angle-adjuster is improved based on bench test. Liability model of seat angle-adjuster system is established according to seat angle-adjuster of key parts failure mode. That provides technical support for the design improvements of seat angle-adjuster.

关键词： Automobile seat Angle-Adjuster Bench Test Reliability Structure Optimization

Analysis of Vehicle seat and Research on Structure Optimization in Front and Rear Impact

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World Journal of Engineering and Technology 2014年第2期2卷 92-99页

作者： Haining Chen Hao Chen Liangjie Wang College of Automotive Engineering Shanghai University of Engineering Science Shanghai China

This paper used the Hyper Mesh and LS-DYNA software to establish a dummy-seat finite element simulation model. The head, chest and neck injury of the dummy were analyzed respectively in the frontal impact and rear impact. It was indicated that modification of seat was needed to meet the requirements. The simulation results showed that the original model cannot provide effective protection for the occupants and need for structural improvements. According to the simulation results of deformation and stress conditions of the seat parts, the original seat structure was improved and optimized for four improvement schemes, including the structure optimization of the seat side panel, the center hinge, framework under the cushion and the backrest lock. The results indicated that the optimized seat improved the occupant protection performance by reducing occupant damage parameters compared with original seat, which illustrated that the optimization basically met the target.

关键词： Front and Rear Impact seat Occupant Injuries Optimization

Finite Element Modelling of Car seat with Hyperelastic and Viscoelastic Foam Material Properties to Assess Vertical Vibration in Terms of Acceleration

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Engineering（科研） 2020年第3期12卷 177-193页

作者： Purnendu Mondal Subramaniam Arunachalam School of Architecture Computing and Engineering University of East London (Docklands Campus) London UK

Primary objective of automobile seats is to offer adequate level of safety and comfort to the seated human occupant, primarily against vibration. Ideally, any sort of automotive seat is constructed by mechanical framework, cushion, backrest and headrest. The frame structures are made of metallic alloys, while the cushion, backrest and headrest are made of polyurethane foam material. During the design phase of automotive seat, the greatest challenge is to assign realistic material properties to foam material;as it is non-linear in nature and exhibit hysteresis at low level stress. In this research paper, a car seat has been modelled in finite element environment by implementing both hyperelastic and viscoelastic material properties to polyurethane foam. The car seat has been excited with the loads due to car acceleration and human object and the effects of vibration in terms of vertical acceleration at different locations have been measured. The aims of this simulation study are to establish a car seat with the foam material properties as accurately as possible and provide a finite element set up of car seat to monitor the vertical acceleration responses in a reasonable way. The RMS acceleration values for headrest, backrest and cushion have been found to be 0.91 mm/sec2, 0.54 mm/sec2 and 0.47 mm/sec2, respectively, which showed that the car seat foam can effectively be modelled through combined hyperelastic and viscoelastic material formulations. The simulation outputs have been validated through real life testing data, which clearly indicates that this computerized simulation technique is capable of anticipating the acceleration responses at different car seat segments in a justified way.

关键词： Car seat Hyperelastic Material Viscoelastic Material Finite Element Vertical Acceleration Vertical Vibration

Rationality of Reincorporating the Reserved seat Provision in the Constitution of The People’s Republic of Bangladesh

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Psychology Research 2019年第3期9卷 116-131页

作者： Tasmiah Nuhiya Ahmed Bangladesh Supreme Court DhakaBangladesh

The Constitution (17th Amendment) Act 2018, passed on this 8th July 2018, provides for the tenure of the reserved seats for women in Parliament to be extended for a period of 25 years from the first day of the 11th parliament. In Bangladesh, there is a consensus in general that women’s political participation is necessary for both the democratic development of the country and women’s empowerment. Studies and research on the constitutionality of the Reserved seat Provision for women in Parliament show that this Reserved seat Provision does not actually help women impact in the political process in Parliament and/or in achieving the goals of women empowerment. Hence, this paper shall discuss how this Reserved seat Provision is affecting the election system, leaving a scope for it to be less democratic, effective, and meaningful. This paper shall highlight that merely a sizable presence of women in Parliament for such a long period won’t aid in achieving the aims and objectives of women empowerment. This paper shall conclude with the recommendation that the Reserved seat Provision may be integrated in the Constitution in a manner that provides for direct election of reserved seat nominations for women in Parliament and that too should not be in the Constitution for an indefinite period.

关键词： reserved seat women empowerment Parliament Constitution Constitutional Amendment Bangladesh