Fatigue life prediction of train wheel shaft based on load spectrum characteristics

Based on the analysis of load spectrum data, the loading sequence and the interaction between loads are considered, a fatigue life prediction model based on load spectrum is proposed. The load spectrum is preprocessed and the probability density function of mean and amplitude are fitted. The running condition of the train is analyzed, the one-dimensional program load spectrum of wheel and axle load is constructed by extrapolating the load spectrum. According to the modified fatigue cumulative damage method, the fatigue life of the axle is predicted with the one-dimensional program load spectrum. The relevant factors that affect the strength of the part are fully considers in the model. It more accurately reflects the objective facts of the component fatigue process. The result has more engineering reference significance and it provides a theoretical basis for the design and manufacture of train axles and ensuring safe operation.

Load Spectrum Compiling and Fatigue Life Estimation of the Automobile Wheel Hub

Background:: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective:: This paper introduces a method to study the fatigue life of car hub based on the road load collected from test site. Methods:: Based on interval analysis, the distribution characteristics of load spectrum are analyzed. The fatigue life estimation of one - dimensional and two - dimensional load spectra is compared by compiling load spectra. Results:: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397,100 km to 529,700 km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimates the fatigue life of wheel hub of the interval is 329900 km to 435200 km, than one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion:: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of auto parts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.

FORMATION OF A TEST SYSTEM FOR CONTROLLING THE PREPAREDNESS OF PLAYERS IN TEAM SPORTS GAMES

Background. Current trends in the development of team sports, changes in the direction and age of the stages of long-term training indicate the need to improve the system of tests to control the training of athletes in these sports, taking into account tasks, program load, functional responsibilities of players and so on. Thus theoretical substantiation of the hierarchical structure of knowledge about the system of tests will allow to improve the system of control and management of training and competitive processes. The aim – on the basis of generalization of theoretical data, advanced practical experience and own experimental researches to substantiate the hierarchical structure of knowledge about system of tests on control of readiness of sportsmen in team sports games. Material and methods: analysis of special, scientific and methodical literature, analysis of documentary materials, pedagogical observation, system method, generalization and systematization of data. Results. On the basis of the system approach the hierarchical structure of the system of knowledge concerning the system of tests of readiness of sportsmen in team sports games in the course of long-term preparation is theoretically substantiated. On the example of such an element of the hierarchy as the requirements for tests in basketball, a fragment of the system of knowledge about tests to control the readiness of athletes in team sports is presented, which provides consideration of tests not only for one player but also for a group of players and the whole team and the focus of tasks and program load at different stages and stages of long-term training. Conclusions. The hierarchical structure of knowledge about the system of tests to control the readiness of athletes in team sports games is theoretically substantiated. A detailed description of such elements of the hierarchy of scientific knowledge as requirements for tests in basketball is given: reliability, specificity, informativeness, connection with the stages of long-term training; connection with sensitive periods of development of physical qualities; connection with the program material of the curriculum for the year; complexity; number of performers; periodicity.

Improving Educational Quality Through Curriculum Development: An Empirical Investigation Using Stakeholder Feedback Data

Using feedback data from stakeholders, the study examines several aspects of the curriculum offered by a program offering entity (POE) in Bangladesh. Analysis of the data shows that the opinions of the stakeholders from various groups resonate together for evaluation areas like need assessment, curriculum mapping, and feedback mechanism. However, opinions expressed by students, both current and alumni, diverge from the opinions expressed by the academic community on matters like “program load.” The qualitative analysis of the text data obtained through some open-ended questions reveals that the respondents support an academic environment free from campus politics and incorporation of more courses related to Information Communication Technology (ICT) for curriculum development.

Hierarchical Cognition causes Task Related Deactivations but not just in Default Mode Regions

The well-known deactivation of the Default Mode Network (DMN) during external tasks is usually thought to reflect the suppression of internally directed mental activity during external attention. In 3 experiments with human participants we organized sequences of task events identical in their attentional and control demands into larger task episodes. We found that DMN deactivation across such sequential events was never constant, but was maximum at the beginning of the episode, then decreased gradually across the episode, reaching baseline towards episode completion, with the final event of the episode eliciting an activation. Crucially, this pattern of activity was not limited to a fixed set of DMN regions but, across experiments, was shown by a variable set of regions expected to be uninvolved in processing the ongoing task. This change in deactivation across sequential but identical events showed that the deactivation cannot be related to attentional/control demands which were constant across the episode, instead it has to be related to some episode related load that was maximal at the beginning and then decreased gradually as parts of the episode got executed. We argue that this load resulted from cognitive programs through which the entire episode was hierarchically executed as one unit. At the beginning of task episodes, programs related to their entire duration is assembled, causing maximal deactivation. As execution proceeds, elements within the program related to the completed parts of the episode dismantle, thereby decreasing the program load and causing a decrease in deactivation.Significance StatementWe prepare breakfasts and write emails, and not individually execute their many component acts. The current study suggests that cognitive entities that enable such hierarchical execution of goal-directed behavior may cause the ubiquitously seen deactivation during external task execution. Further, while this deactivation has previously been associated with a defined set of the so called default mode regions, current study demonstrates that deactivation is shown by any region not currently involved in task execution, and in certain task episodes can even include attention related fronto-parietal regions as well as primary sensory and motor regions.

Realistic Simulation of Railway Operation on the RAILBCOT Test Stand

The aim of the article is to present the necessity of completion of the test stand of brake components of railway vehicles with the equivalent railway operation load simulator for the research of the wheel wear on it. The other aim of presented research needs is to perform the analysis of the equivalent conicity as a parameter for the rail vehicles in operation ride properties prediction. The sub aims are the change of frame, wheel, braking forces load via SIMRAIL simulator program load collection performance.