Longitudinal sliding resistance characteristics of the WJ-8 conventional resistance fastner

2021 ◽  
pp. 095440972199890
Author(s):  
Zhiping Zeng ◽  
Wang Di ◽  
Abdulmumin Ahmed Shuaibu ◽  
Zhihui Zhu ◽  
Zhihua Lin
Keyword(s):  
Linear Trend ◽  
Frictional Coefficient ◽  
Element Model ◽  
Skid Resistance ◽  
Vertical Load ◽  
Resistance Variation ◽  
Longitudinal Resistance ◽  
Sliding Resistance ◽  
The Relationship ◽  
Variation Rule

In this paper, the longitudinal resistance and displacement of the WJ-8 conventional resistance fastener under vertical and torque loadings were experimentally conducted and the relationship between longitudinal resistance and displacement was established. To validate the experimental results, numerical simulation using a finite-element model of the fastener was established to obtain the longitudinal resistance variation of the conventional-resistance. Results of the analysis show that both results of the experiment and simulation are in agreements. Furthermore, the skid resistance frictional coefficient of the fastener system under the vertical load was studied and its variation rule under both vertical and torque loads was obtained. The longitudinal sliding resistance of fasteners under different torques and/or vertical loads followed a linear trend. Under load and no-load conditions, the skid-resistance frictional coefficient of the fastener system varied significantly.

scholarly journals Research on the longitudinal mechanical behaviours of subway turnouts of large slope under train braking force

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110283
Author(s):  
Zhiping Zeng ◽  
Ji Hu ◽  
Chunyu Tian ◽  
Ping Li ◽  
Xiangdong Huang ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Change ◽  
Mechanical Characteristics ◽  
Element Model ◽  
Longitudinal Displacement ◽  
Longitudinal Deformation ◽  
Longitudinal Stiffness ◽  
Mechanical Behaviours ◽  
Longitudinal Resistance ◽  
Safety And Stability

To study subway turnouts’ adaptability to steep gradients, a finite element model of a metro No. 9 simple turnout was established. The main works include: (1) The train’s most unfavourable loading condition was modelled. (2) The turnout’s longitudinal displacement and stress were analysed with different gradients under the train braking load, temperature change load and a combination of the two, to determine the structure’s safety and stability under the most unfavourable working conditions. (3) The turnout structure’s cumulative longitudinal deformation under reciprocating load was studied. Both a fastener longitudinal resistance-displacement experiment under reciprocating load and a numerical simulation of No. 9 turnout modelled by the finite element modelling software, ANSYS, were carried out to study the gradient’s influence on the turnout’s longitudinal mechanical characteristics. (1) The turnout’s longitudinal displacement and stress increase linearly with an increase in gradient and temperature change, both of which are unfavourable to the turnout structure. As the gradient increases from 0‰ to 30‰, the longitudinal stress and displacement increase by more than 10%. (2) The turnout’s rail strength and displacement on a 30‰ slope under the most unfavourable load conditions are within the specification limitations. (3) Under reciprocating load, the fastener longitudinal stiffness decreases and the maximum and residual longitudinal displacement of the switch rail increase; an increased gradient intensifies these effects on the turnout.

scholarly journals Effect of number of medications and use of potentially inappropriate medications on frailty among early-stage older outpatients

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yuya Uragami ◽  
Kazuhiro Takikawa ◽  
Hajime Kareki ◽  
Koji Kimura ◽  
Kazuyuki Yamamoto ◽  
...  
Keyword(s):  
Early Stage ◽  
Linear Trend ◽  
Cross Sectional Study ◽  
Potentially Inappropriate Medications ◽  
Sectional Study ◽  
Antithrombotic Drugs ◽  
Cross Sectional ◽  
The Relationship ◽  
Inappropriate Medications ◽  
Frailty Score

Abstract Background Frailty is an urgent concern among an aging population worldwide. However, the relationship between frailty and number and types of medications has not been studied in detail among early-stage older patients, and it is unclear what prescriptions may have a role in preventing frailty. This study aimed to clarify the effects of number of medications and use of potentially inappropriate medications (PIMs) on frailty among early-stage older outpatients in Japan. Methods A cross-sectional study was undertaken. Frailty scores and medications of outpatients aged 65–74 years who regularly visited community pharmacies were investigated. Frailty scores were classified as 0 (non-frailty), 1–2 (pre-frailty), and ≥ 3 (frailty). The association between frailty and number of medications was analyzed by age and compared between PIM use and non-use groups. The proportion of patients who used PIMs was also analyzed by frailty score. Results Of 923 older outpatients, 49 (5.3%) and 318 (34.5%) patients had frailty and pre-frailty scores, respectively. The numbers of medications among patients with pre-frailty and frailty were significantly higher than among those with non-frailty (p <  0.001 for both). A similar increase was shown for PIM use groups aged 69–71 and 72–74 years, but not for the PIM use group aged 65–68 years and all groups without PIM use. An increasing linear trend was observed for the relationship between the proportion of patients who used any PIM, as well as some subcategories of PIMs (such as NSAIDs, benzodiazepines, loop diuretics and antithrombotic drugs) and frailty score. Conclusions Unnecessary medication use among early-stage older outpatients, especially patients aged ≥69 years who use PIMs and many medications, seems to be associated with frailty, but further research is needed to confirm these findings.

scholarly journals Association Between Frailty and Gut Microbiota Metabolite TMAO in Older People With Cardiovascular Disease

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 210-211
Author(s):  
Wei He ◽  
Hua Wang ◽  
Jiefu Yang
Keyword(s):  
Older Adults ◽  
Cardiovascular Diseases ◽  
Gut Microbiota ◽  
Linear Trend ◽  
Frailty Index ◽  
Concentration Data ◽  
Dependent Relationship ◽  
The Status ◽  
Cubic Spline Curve ◽  
The Relationship

Abstract The potential for the gut microbiota to affect health has particular relevance for older adults. Recent evidence suggests that microbiota-derived metabolites may modulate aging-related changes in immunity, sarcopenia, and cognitive function, all of which are elements of frailty. Trimethylamine N-oxide (TMAO) produced by the metaorganismal metabolism of choline, has been implicated in disease pathogenesis. However, relatively little geroscience research has been carried out on TMAO，and even less on other gut microbiota metabolites. The purpose of this study was to explore the relationship between frailty and circulating TMAO concentration. Data and fasting blood samples came from a prospective comprehensive geriatric assessment cohort of older adults (age≥65, n=451) with cardiovascular diseases. The frailty index based on the accumulated deficits model (48 variables) was used for evaluating the status of frailty. TMAO levels differed between groups with a significant increase for people with frailty (p＜0.001). Compared with the lowest quartile of TMAO levels, patients in the highest quartile had increased 3.07-fold risk of frailty (OR=3.07, 95%CI, 1.69-2.97). After adjusting for age, gender, BMI, history of diseases, hsCRP, LDLc, TMAO levels remained associated with frailty (OR=2.11, 95%CI, 1.01-4.38). Similarly, a cubic spline curve showed a dose-dependent relationship between the odds ratio for the risk of frailty and circulating TMAO in a linear trend (p = 0.006). This study suggests that circulating TMAO are independently associated with frailty in older adult with cardiovascular diseases. Efforts to further characterize the relationship between gut microbiota metabolite and frailty should be further pursued.

Numerical Analysis of Bridge Expansion-Induced Rail Deformation of Ballast Truck

2014 ◽  
Vol 580-583 ◽  
pp. 3208-3214 ◽  
Author(s):  
Zhen Wei Xiong ◽  
Xin Ling Liang ◽  
Xian Xing Dai ◽  
Ping Wang
Keyword(s):  
Granular Flow ◽  
Element Model ◽  
Discrete Element Model ◽  
Board Structure ◽  
Vertical Deformation ◽  
Two Dimensional ◽  
Running Safety ◽  
Bridge Plate ◽  
Ballast Track ◽  
The Relationship

when the ballast track stretch with the bridge, ballast which is near expansion joint will move confusedly. As a result, rail produced vertical deformation. The deformation will affect the running safety and comfortability of train. At present, there are two kinds of treatments which are cover board structure and baffle structure to deal ballast’s movement. Aiming at the different modes of stretching when the two kinds of structures and different arrangement condition of bridge plate are applied, the rail-sleeper-ballast discrete element model is developed by the method of two-dimensional granular flow. The relationship between rail deformation and bridge expansion is analyzed on the foundation of the model. Results show as flows: when bridge extends or shortens, rail always produced upwarp deformation. Bridge plate should arrange asymmetrically. Like this, the rail deformation decrease by 40%. And adopting the baffle structure can effectively reduce the influence of bridge expansion in ballast truck.

Finite Element Analysis of the ESTELA M1 Airplane Firewall (Representative Specimen)

2011 ◽  
Author(s):  
V. Ramirez-Elias ◽  
E. Ledesma-Orozco ◽  
H. Hernandez-Moreno
Keyword(s):  
Finite Element ◽  
Federal Aviation Administration ◽  
Element Model ◽  
Maximum Load ◽  
Load Factor ◽  
Representative Specimen ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper shows the finite element simulation of a representative specimen from the firewall section in the AEROMARMI ESTELA M1 aircraft. This specimen is manufactured in glass and carbon / epoxy laminates. The specimen is subjected to a load which direction and magnitude are determined by a previous dynamic loads study [10], taking into account the maximum load factor allowed by the FAA (Federal Aviation Administration) for utilitarian aircrafts [11]. A representative specimen is manufactured with the same features of the firewall. Meanwhile a fix is built in order to introduce the load directions on the representative specimen. The relationship between load and displacement is plotted for this representative specimen, whence the maximum displacement at the specific load is obtained, afterwards it is compared with the finite element model, which is modified in its laminate thicknesses in order to decrease the deviation error; subsequently this features could be applied to perform the whole firewall analysis in a future model [10].

scholarly journals Thermomechanical Couplings in Aircraft Tire Rolling/Sliding Modeling

2011 ◽  
Vol 274 ◽  
pp. 81-90 ◽  
Author(s):  
Ange Kongo Kondé ◽  
Iulian Rosu ◽  
F. Lebon ◽  
L. Seguin ◽  
Olivier Brardo ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Thermal Effects ◽  
Coulomb Friction ◽  
Large Deformations ◽  
Element Model ◽  
Slip Angle ◽  
Tire Model ◽  
Vertical Load ◽  
Coulomb Friction Law ◽  
Lateral Friction

This paper presents a finite element model for the simulation of aircraft tire rolling. Large deformations, material incompressibility, heterogeneities of the material, unilateral contact with Coulomb friction law are taken into account. The numerical model will allow estimating the forces in the contact patch - even in critical and extreme conditions for the aircraft safety and security. We show the influence of loading parameters (vertical load, velocity, inflating pressure) and slip angle on the Self Aligning torque and on the lateral friction coefficient. A friction coefficient law corresponding to Chichinadze model is considered to take into account thermal effects in the aircraft tire model behaviour.

scholarly journals The relationship between SPAD chlorophyll and disease severity index in Ganoderma-infected oil palm seedlings

2019 ◽  
Vol 17 (3) ◽  
pp. 355-358 ◽  
Author(s):  
M.R.M. Rakib ◽  
A.H. Borhan ◽  
A.N. Jawahir
Keyword(s):  
Chlorophyll Content ◽  
Disease Severity ◽  
Oil Palm ◽  
Single Photon ◽  
Linear Trend ◽  
Severity Index ◽  
Quadratic Model ◽  
Wood Block ◽  
Disease Severity Index ◽  
The Relationship

Establishment of disease in oil palm seedlings through artificial inoculation of Ganoderma are widely used for studies of various aspects of plant pathology, including epidemiology, etiology, disease resistance, host-parasite interaction and disease control. The estimation of chlorophyll content in the infected seedlings possibly could provide a good indicator for degree of disease or infection, and changes during pathogenesis. Thus, the objective of this study was to evaluate the relationship between disease severity index (DSI) and chlorophyll content in Ganoderma infected oil palm seedlings. Three-month-old oil palm seedlings were infected with Ganoderma inoculum on rubber wood block (RWB), where 44 isolates of Ganoderma were tested. Disease severity index (DSI) and chlorophyll content using a single-photon avalanche diode (SPAD) meter were recorded at 4 weeks interval for a period of 24 weeks after inoculation (WAI). Pearson's correlation analysis and regression analysis were performed to evaluate the relationship between the variables. It was found that the relationship between DSI and SPAD chlorophyll value was inversely proportional (R = -0.92) in a linear trend (R2 = 0.85). Furthermore, the increasing trend of the DSI across the weeks were fitted in a quadratic model (R2 = 0.99). In contrast, the SPAD chlorophyll value declined in a linear trend (R2 = 0.98). The SPAD chlorophyll value could be considered as a better alternative over the DSI as the SPAD chlorophyll value was strongly related to DSI, as well as able to detect physiological changes in the infected oil palm seedlings at the early stages of pathogenesis. J Bangladesh Agril Univ 17(3): 355–358, 2019

scholarly journals Assessment of the Relationship between Cerebrospinal Meningitis and Climate Variables in Kaduna State, Nigeria

2021 ◽  
pp. 33-41
Author(s):  
Joyce Imara Nchom ◽  
A. S. Abubakar ◽  
F. O. Arimoro ◽  
B. Y. Mohammed
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Linear Trend ◽  
Pearson Correlation ◽  
Maximum Temperature ◽  
Data Set ◽  
International Research Institute ◽  
Wind Speed Maximum ◽  
Weather Parameters ◽  
The Relationship

This study examines the relationship between Meningitis and weather parameters (air temperature, maximum temperature, relative humidity, and rainfall) in Kaduna state, Nigeria on a weekly basis from 2007–2019. Meningitis data was acquired weekly from Nigeria Centre for Disease Control (NCDC), Bureau of Statistics and weather parameters were sourced from daily satellite data set National Oceanic and Atmospheric Administration (NOAA), International Research Institute for Climate and Society (IRI). The daily data were aggregated weekly to suit the study. The data were analysed using linear trend and Pearson correlation for relationship. The linear trend results revealed a weekly decline in Cerebro Spinal Meningitis (CSM), wind speed, maximum and air temperature and an increase in relative humidity and rainfall. Generally, results reveal that the most important explanatory weather variables influencing CSM amongst the five (5) are the weekly maximum temperature and air temperature with a positive correlation of 0.768 and 0.773. This study recommends that keen interest be placed on temperature as they play an essential role in the transmission of this disease and most times aggravate the patients' condition.

scholarly journals Comparative Analysis of Static Loading Performance of Rigid and Flexible Road Wheel based on Finite Element Method

2020 ◽  
Vol 70 (1) ◽  
pp. 41-46
Author(s):  
Yaoji Deng ◽  
Youqun Zhao ◽  
Mingmin Zhu ◽  
Zhen Xiao ◽  
Qiuwei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Static Loading ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Vertical Load ◽  
New Type ◽  
Stress And Deformation ◽  
Nonlinear Finite Element Model

To overcome the shortcomings of traditional rigid road wheel, such as poor damping effect and low load-bearing efficiency, a new type of flexible road wheel, having a unique suspension-bearing mode, was introduced. The three-dimensional nonlinear finite element model of rigid and flexible road wheel, considering the triple nonlinear characteristics of geometry, material and contact, is established for numerical investigation of static loading performance. The accuracy of the finite element model of the rigid and flexible road wheel is verified by static loading experiment. The static loading performance of the rigid and flexible road wheels is numerically analyzed. The influence of vertical load on maximum stress and deformation of the rigid and flexible wheels is also studied. The results show that the contact pressure uniformity of the flexible road wheel is better than that of the rigid road wheel under the static vertical load, but the maximum stress and deformation of the flexible road wheel are greater than that of the rigid road wheel. However, this problem can be solved by increasing the number of hinge sets and optimising the joints. The research results provide theoretical basis for replacing rigid road wheel with flexible road wheel, and also provide reference for structural optimisation of flexible road wheel.

The Relationship of Normal and Abnormal Microstructural Proliferation to the Mitral Valve Closure Sound

2005 ◽  
Vol 127 (1) ◽  
pp. 134-147 ◽  
Author(s):  
Daniel R. Einstein ◽  
Karyn S. Kunzelman ◽  
Per G. Reinhall ◽  
Mark A. Nicosia ◽  
Richard P. Cochran
Keyword(s):  
Mitral Valve ◽  
Volume Fraction ◽  
Contrast Material ◽  
Element Model ◽  
Peak Frequency ◽  
Material Behavior ◽  
Small Scale ◽  
Valve Closure ◽  
Valvular Function ◽  
The Relationship

Background : Many diseases that affect the mitral valve are accompanied by the proliferation or degradation of tissue microstructure. The early acoustic detection of these changes may lead to the better management of mitral valve disease. In this study, we examine the nonstationary acoustic effects of perturbing material parameters that characterize mitral valve tissue in terms of its microstructural components. Specifically, we examine the influence of the volume fraction, stiffness and splay of collagen fibers as well as the stiffness of the nonlinear matrix in which they are embedded. Methods and Results: To model the transient vibrations of the mitral valve apparatus bathed in a blood medium, we have constructed a dynamic nonlinear fluid-coupled finite element model of the valve leaflets and chordae tendinae. The material behavior for the leaflets is based on an experimentally derived structural constitutive equation. The gross movement and small-scale acoustic vibrations of the valvular structures result from the application of physiologic pressure loads. Material changes that preserved the anisotropy of the valve leaflets were found to preserve valvular function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valvular function. These changes were manifest in the acoustic signatures of the valve closure sounds. Abnormally, stiffened valves closed more slowly and were accompanied by lower peak frequencies. Conclusion: The relationship between stiffness and frequency, though never documented in a native mitral valve, has been an axiom of heart sounds research. We find that the relationship is more subtle and that increases in stiffness may lead to either increases or decreases in peak frequency depending on their relationship to valvular function.

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