A Kinematics Velocity Reliability Analyzing Method for Complex Planar Linkage Mechanism Based on Equal-Effective Mechanics Model

2016 ◽  
Author(s):  
Jingyi Liu ◽  
Yugang Zhang ◽  
Wei Guo ◽  
Cong Sun
Keyword(s):  
Effective Length ◽  
Joint Clearance ◽  
Linkage Mechanism ◽  
Kinematic Parameters ◽  
Component Size ◽  
Aircraft Cabin ◽  
Mechanics Model ◽  
Surface Method ◽  
Planar Linkage Mechanism ◽  
The Relationship

The planar linkage mechanism (PLM) is a kind of familiar mechanism. The accuracy of its kinematic parameters, such as displacement or velocity, is crucial to accomplish its function. The parameters are not always precise due to the indeterminacy of some influencing factors. This paper proposes a methodology to analyze the velocity reliability of PLM based on the equal-effective mechanics model (EMM), with the effect of joint clearance, component size randomness and applied force randomness considered. More specifically, how these factors would influence the EMM is studied and then the motion law and risk velocity point of certain part can be obtained. To model the joint clearance exactly, the concept of effective length is recommend. The Response Surface Method (RSM) is used to express the relationship between input parameters and output parameter (velocity), based on which the reliability analysis is conducted. The sensitivities of the parameters are expressed by Sobol variance analyzing method. Finally a certain aircraft cabin door retractable mechanism (one sort of complex planar linkage mechanism) is selected as an example, showing that the approach proposed this article has a great value to be used for engineering object.

Reducing undesirable vibrations of planar linkage mechanism with joint clearance

2018 ◽  
Vol 32 (2) ◽  
pp. 559-565 ◽  
Author(s):  
Zheng Feng Bai ◽  
Xin Jiang ◽  
Fei Li ◽  
Ji Jun Zhao ◽  
Yang Zhao
Keyword(s):  
Joint Clearance ◽  
Linkage Mechanism ◽  
Planar Linkage Mechanism

scholarly journals Effect of scent on comfort of aircraft passengers

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S273-S280
Author(s):  
Xinhe Yao ◽  
Yu Song ◽  
Peter Vink
Keyword(s):  
Completion Time ◽  
Aircraft Cabin ◽  
Different Types ◽  
The Relationship ◽  
Over Time

BACKGROUND: Scents may influence the perceived comfort of an environment. There are only a few studies conducted on the relationship between scent and comfort in aircraft cabin. OBJECTIVES: The goal of this research is to explore whether relationships between scents and perceived comfort can be found for passengers in an aircraft cabin. METHODS: 276 participants joined an experiment in a Boeing 737 fuselage. The participants were divided into nine groups and each joined a session for 60 minutes with the exposure to different scents. The effect of the odor was measured by a set of questionnaires at the beginning and at the end of the session. Results of questionnaires were analyzed regarding the effects on the completion time, of the type of scents, of the intensity of the scent and on gender. RESULTS: Significant differences were found at the beginning and at the end of the experiment regarding comfort and emotion, but sometimes no relations could be established. The influence of different scents on comfort/discomfort varied and changed over time. However, in all scenarios, participant’ scores on emotion decreased. Additionally, the added scents influenced the linearity between the changes in comfort and discomfort. CONCLUSIONS: Smell could influence the perceived comfort/discomfort of aircraft passengers over time, and different types of smells have different effects on passengers. The preferences on scents are diverse, which highlights the need for personalization in aircraft cabin design.

ANN-Based Structure Optimization with Fatigue Reliability Constrains

2012 ◽  
Vol 204-208 ◽  
pp. 3128-3131
Author(s):  
Li Rong Sha ◽  
Yue Yang
Keyword(s):  
Structural Optimization ◽  
Objective Function ◽  
Reliability Analysis ◽  
Response Surface ◽  
Minimum Weight ◽  
Structure Optimization ◽  
Fatigue Reliability ◽  
Ann Model ◽  
Surface Method ◽  
The Relationship

The ANN-based optimization for considering fatigue reliability requirements in structural optimization was proposed. The ANN-based response surface method was employed for performing fatigue reliability analysis. The fatigue reliability requirements were considered as constraints while the weight as the objective function, the ANN model was adopted to establish the relationship between the fatigue reliability and geometry dimension of the structure, the optimal results of the structure with a minimum weight was reached.

scholarly journals KINEMATIC PARAMETERS OF JUMP SHOT IN ELITE MALE BASKETBALL PLAYERS

2019 ◽  
pp. 237
Author(s):  
Emilija Stojanović ◽  
Marko Radenković ◽  
Saša Bubanj ◽  
Ratko Stanković
Keyword(s):  
Body Height ◽  
The Body ◽  
Release Time ◽  
Kinematic Parameters ◽  
Basketball Players ◽  
The Relationship ◽  
Lower Angle

The primary aim of this study was to determine kinematic parameters of jump shot in elite male basketball players, by analyzing the release time for shooting, the angle of entry, and ball spin and. The secondary aim of this study was to examine possible differences in these kinematic parameters among the players associated with their playing position. Eighteen male basketball players (7 guards, 8 forwards, 3 centers) from six Serbian senior teams were tested. 94Fifty basketball sensor was used to obtain the following kinematic parameters of jump shot). The highest average measured values of shot release time were found in centres (1.23±0.23 s) and the lowest in guards (1.07±0.28 s), although these differences were not statistically significant. Further, centres had a lower angle of entry (36.6±2.08°) than guards (40.54±4.76°) and forwards (42.05±3.77°). The highest value of backspin was obtained by forwards (130±11.91 rotations / min). There were no significant differences between guards, forwards and centers in any kinematic variables (p>.01). The relationship between the body height and angle of entry was not significant (p>0.05). In conclusion, compared to centers, guards and forwards showed similar results for the examined variables. This evidence seems to support the theory that compared to guards and forwards centres have the weaker shooting techniques. Coaches should encourage all players, especially centers, to shoot from all positions.

scholarly journals Optimization of Superplastic Forming Process of AA7075 Alloy for the Best Wall Thickness Distribution

2021 ◽  
Vol 6 (4) ◽  
pp. 251-261
Author(s):  
Manh Tien Nguyen ◽  
Truong An Nguyen ◽  
Duc Hoan Tran ◽  
Van Thao Le
Keyword(s):  
Wall Thickness ◽  
Deformation Temperature ◽  
Numerical Optimization ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Forming Process ◽  
Wall Thickness Distribution ◽  
Surface Method ◽  
Series Of Experiments ◽  
The Relationship

This work aims to optimize the process parameters for improving the wall thickness distribution of the sheet superplastic forming process of AA7075 alloy. The considered factors include forming pressure p (MPa), deformation temperature T (°C), and forming time t (minutes), while the responses are the thinning degree of the wall thickness ε (%) and the relative height of the product h*. First, a series of experiments are conducted in conjunction with response surface method (RSM) to render the relationship between inputs and outputs. Subsequently, an analysis of variance (ANOVA) is conducted to verify the response significance and parameter effects. Finally, a numerical optimization algorithm is used to determine the best forming conditions. The results indicate that the thinning degree of 13.121% is achieved at the forming pressure of 0.7 MPa, the deformation temperature of 500°C, and the forming time of 31 minutes.

Cable effective length model error-based bridge performance warning method under thermal action

2021 ◽  
pp. 136943322110480
Author(s):  
Yan Wang ◽  
Dong-Hui Yang ◽  
Yu-Zheng Zhou ◽  
Ting-Hua Yi
Keyword(s):  
Thermal Action ◽  
Dynamic Responses ◽  
Effective Length ◽  
Time Variability ◽  
Long Span ◽  
The North ◽  
Static Responses ◽  
Bridge Performance ◽  
The Relationship

The cables of long-span cable-stayed bridges are subjected to substantial tension during long-term service and are more susceptible to corrosion and fatigue failure than concrete structures. Most existing structural health monitoring (SHM) systems do not have monitoring equipment to directly measure cable length, and long-term monitoring of the change in cables is less involved. The displacement response of a bridge is induced by the combination of dynamic effects (wind and highways) and quasi-static effects (temperature). In this paper, the dynamic responses were eliminated by averaging the displacement data for 10 min, and the relationship between temperature and displacement was studied. Based on the monitoring data, the distribution of the thermal field for the bridge was studied and the time variability of the tower displacement was investigated. The correlation was analyzed to study the relationship between the temperature and the tower displacements, the north tower–south tower distance and the tower–girder distances. A strong linear relationship between the temperature and quasi-static responses of the displacements was observed. The thermal expansion coefficient of the effective length of cables was proposed as a quantitative index for long-term cable monitoring. The error in the cable effective length is proposed as the warning index for performance warning research. The results show that the proposed performance warning method can monitor cables and perform warnings when the cable is damaged.

KINETOSTATIC ANALYSIS FOR FOUR-BAR LINKAGE MECHANISM OF PROSTHETIC KNEE JOINT

2019 ◽  
Vol 19 (04) ◽  
pp. 1950018 ◽  
Author(s):  
XUHUI LIU ◽  
TIANTIAN GUO ◽  
JIAHAO ZHANG ◽  
GUANG YANG ◽  
LUCHAN SUN ◽  
...  
Keyword(s):  
Knee Joint ◽  
Group Method ◽  
Linkage Mechanism ◽  
Analysis Software ◽  
Prosthetic Knee ◽  
Damping Effect ◽  
D’Alembert Principle ◽  
Prosthetic Knee Joint ◽  
Four Bar Linkage ◽  
The Relationship

In this paper, a mathematical model of four-bar linkage mechanism is built to investigate the prosthetic knee joint, by means of the bar group method, and the motion of the prosthetic knee joint is simulated by motion analysis software. In the state of motion of the four linkage mechanism, to the moving component of the mechanism, the relationship between the moving displacement, velocity and acceleration are obtained. On the basis of the above investigation, dynamic statics analysis for the moving component of four-bar linkage mechanism are completed by the ‘D’Alembert principle. The research results show that, with the change of the rotating angle of the active part, the counter-force of rotating pair and the balance torque on active component are all changeable, which will provide a theoretical basis for the design of prosthetic knee joint mechanism with longer life and better damping effect.

Sign in / Sign up

Export Citation Format

Share Document