Purpose: This study aims to identify the concussion-related training and education needs of Gaelic Athletic Association(GAA) coaches in Ireland,as well as the preferred method of concussion education delivery.Methods:...Purpose: This study aims to identify the concussion-related training and education needs of Gaelic Athletic Association(GAA) coaches in Ireland,as well as the preferred method of concussion education delivery.Methods: We used a self-report questionnaire to collect data from a convenience sample of 108 GAA coaches in Ireland. Data were captured on(1) informational needs and desires,(2) preferred methods of delivery, and(3) concussion practices and procedures. Questionnaires were completed electronically from June 3 rd–September 29 th, 2015.Results: Coaches indicated that they were most interested in receiving information about the(1) signs and symptoms of concussion,(2) assessment of concussion, and(3) return-to-play guidelines. Over two-thirds of participants indicated that in-person training would be the most effective mode of delivery of concussion education for this population. Additionally, only 10% coaches reported that before the start of the season they talked to their athletes about concussion management and safety, and this was more common among coaches who reported being formally educated about concussion.Conclusion: Our findings reveal a disconnect between the concussion education needs and the education that is currently provided to GAA coaches, in terms of content and delivery modality. Our results suggest a need for a multifaceted approach to concussion education, tailored to the needs and learning preferences of the target population.展开更多
Context and Objective: Hamstring strain is a common injury in football and it causes a significant amount of time lost from competition and training. Since poor flexibility is thought to predispose to muscle strain, s...Context and Objective: Hamstring strain is a common injury in football and it causes a significant amount of time lost from competition and training. Since poor flexibility is thought to predispose to muscle strain, stretching is routinely recommended during warm-up routines by coaches to prevent injuries. However, available evidence suggests that pre-exercise stretching (PES), especially static stretching, has no benefit on injury rates and may even reduce performance in explosive type activities. We designed this study to assess the attitudes, beliefs and practices of football coaches regarding stretching in the prevention of hamstring strains. Design: A cross-sectional survey. Setting: Mauritius Football Association (MFA). Participants: 26 football coaches registered with the MFA. Intervention: Questionnaires were distributed to football coaches of the MFA via sports officers. Questionnaires were then collected two weeks after distribution. Main Outcome Measures: Attitudes, beliefs and practices of football coaches regarding stretching in the prevention of ham-string strains. Results: MFA coaches held generally positive attitudes and beliefs towards stretching. 88% of coaches felt that PES is beneficial and 93% believed that PES prevents hamstring strains. The majority of coaches recommended stretching after warming up (81%) and after the training session (93%). 76% of coaches also advised stretching outside the training sessions. 96% of coaches used static stretching to stretch the hamstrings. The hamstrings were stretched on average for 4 times at each training session and the mean duration of a static stretch was 12 seconds. Conclusions: Nearly all coaches believed that PES prevents hamstring strains although evidence is limited. Some of the coaches’ beliefs and practices were not in line with current recommendations. Coaches reported that their stretching practices would be most likely influenced by scientific research. Thus there is an urgent need to devise awareness and training programmes in this area.展开更多
Gymnasts are exposed to intense training,frequent competitions,controlled diets and high levels of psychological distress in youth age.These aspects can negatively affect athletic performance and have health consequen...Gymnasts are exposed to intense training,frequent competitions,controlled diets and high levels of psychological distress in youth age.These aspects can negatively affect athletic performance and have health consequences.Accordingly,if the coaches do not possess adequate knowledge and specific multi-disciplinary skills related to sports practice and health pedagogy,young athletes can be exposed to different health risks.The aim of this study is to investigate the knowledge and attitudes of coaches and identify any education needs to enhance or preserve the gymnasts’well-being.The sample is represented by 98 Italian rhythmic gymnastics coaches of different levels.The data were obtained by using structured and anonymous questionnaires with open and closed answers administered through interview.The aspects examined are related to nutrition,food supplements,overtraining syndrome,educational topics,gymnasts’hassles and trainings needs of coaches.Critical aspects that emerge from this study show the need for specific scientific training and support for coaches.This objective can be achieved by providing constant technical and scientific support,in order to make the coaches fully aware of their educational,pedagogical and long-term health responsibilities of their athletes.展开更多
Coaches experience considerable stress and anxiety in their pursuit of both team and individual success. Although there has been an increase in research aimed at promoting and managing the mental health of student-ath...Coaches experience considerable stress and anxiety in their pursuit of both team and individual success. Although there has been an increase in research aimed at promoting and managing the mental health of student-athletes, the mental well-being of coaches remains underexplored. Research indicates that the mental health profiles of coaches are similar to those of elite athletes [1] and should receive comparable attention. The introduction of Name, Image, and Likeness (NIL) legislation, along with the rise of the Transfer Portal in collegiate athletics, has presented student-athletes with new and unexpected options, which also bring novel challenges to coaches and potentially impact elite-level coaches’ mental health. This manuscript will identify three categories of stressors—performance, organizational, and self-related—that affect elite men’s college basketball coaches, highlighting how NIL and the Transfer Portal exacerbate those stressors and their impact on coaches’ mental health.展开更多
The aim of this study was to analyse the rate and content of 10,430 messages,sent by 21 handball coaches in 21 matches,in relation to score and match phase.Three situations were defined as regards score:large victory,...The aim of this study was to analyse the rate and content of 10,430 messages,sent by 21 handball coaches in 21 matches,in relation to score and match phase.Three situations were defined as regards score:large victory,tight game,and large defeat;and four phases for match phase:part 1 and 2 of first half,and part 1 and 2 of second half.Message rates were calculated by dividing the number of messages sent at each level of score and match phase by the elapsed time.To calculate the content,messages were coded using Coach Analysis and Intervention System and percentages were calculated according to score and match phase.Chi-square analysis showed statistically significant differences for rate of messages by score(χ^(2)=211.06,df=2,sig<0.001),and match phase(χ^(2)=23.704,df=3;sig<0.001);and for percentage of content by score(χ^(2)=444.011,df=42,sig<0.001)and match phase(χ^(2)=201.706,df=63,sig<0.001).Results can help to establish guidelines to increase the quality of coaches’speech.展开更多
China’s latest exportan overseas coaching legion,received lots of attention as well as understanding in Beijing 0n the evening of August 23, one day before the closing of the Beijing Olympics, the Chinese diving team...China’s latest exportan overseas coaching legion,received lots of attention as well as understanding in Beijing 0n the evening of August 23, one day before the closing of the Beijing Olympics, the Chinese diving team was only one gold short of its dream. The last diving event was the men’s 10 meters platform. The Chinese audience was confident that their divers would secure this gold.展开更多
Purpose It is well recognised that injury prevention training can reduce injury incidence,however current coach education pathways do not provide grass-root coaches with the knowledge and confidence to deliver such tr...Purpose It is well recognised that injury prevention training can reduce injury incidence,however current coach education pathways do not provide grass-root coaches with the knowledge and confidence to deliver such training to youth players.The aim of this study was to explore differences in knowledge,understanding,attitude and confidence to deliver such injury prevention training in three European countries.Methods A total of 269 grass-root soccer coaches from 3 European countries(Czech Republic,UK,Spain)were recruited for this study.A validated questionnaire exploring knowledge,understanding,attitude towards and confidence to deliver youth injury prevention training was completed prior to a 2 h workshop on injury prevention training.Differences between countries was examined using Bayesian factors to quantify the evidence for and against the hypothesis of independence(H0)by assuming a Poisson sampling scheme(as there was no a priori restriction on any cell count,nor on the grand total)(BF10 Poisson).Results Current knowledge,attitude and confidence to deliver injury prevention training to youth players was poor across all three European countries.Relatively few coaches were currently using injury prevention training in their coaching sessions(23%).There were some country specific differences for attitude towards injury prevention training and confidence to deliver injury training,with Spanish coaches reporting a more positive attitude and confidence to deliver such training.Significantly fewer coaches in the UK were using injury prevention training compared to coaches in Spain and the Czech Republic.Conclusion As coaches identified a need for coach education and few were delivering injury prevention training,there is a clear need to embed and implement this programme into the grassroots coaching framework of sports governing bodies to improve adoption,implementation and maintenance.展开更多
Since it's made up of over 7,000 islands,the Philippines is not a nation with a well‑developed railway transportation.That means coach buses are going to be your best bet for getting city‑to‑city.There is a small ...Since it's made up of over 7,000 islands,the Philippines is not a nation with a well‑developed railway transportation.That means coach buses are going to be your best bet for getting city‑to‑city.There is a small light rail system called the Light Rail Transit(LRT)in the Metro Manila area,but it's desperately inefficient.展开更多
To address the challenges of long commuting times,traffic congestion,high energy consumption,and emissions in inter-city travel,a new type of flying coach has been developed.This innovation aims to significantly short...To address the challenges of long commuting times,traffic congestion,high energy consumption,and emissions in inter-city travel,a new type of flying coach has been developed.This innovation aims to significantly shorten inter-city commuting times,enhance travel efficiency,and simultaneously reduce energy consumption and emissions.The flying coach integrates rail power supply technology,an intelligent operating system,and advanced new materials,comprising a catenary power supply guide rod and various sensor components.Based on analysis of traditional aircraft design principles,the research team simulated the design of the rail-powered flying coach using software such as AutoCAD and SolidWorks for three-dimensional modeling.The analysis results indicate that,compared to traditional aircraft and rail trains,the design of the new flying coach reduces its overall weight while maintaining carrying capacity,thereby improving commuting efficiency and environmental performance.This development lays a solid foundation for creating a greener,more efficient,and convenient inter-city transportation network.展开更多
In order to help athletes optimize their performances in competitions while prevent overtraining and the risk of overuse injuries,it is important to develop science-based strategies for optimally designing training pr...In order to help athletes optimize their performances in competitions while prevent overtraining and the risk of overuse injuries,it is important to develop science-based strategies for optimally designing training programs.The purpose of the present study is to develop a novel method by the combined use of optimal control theory and a training-performance model for designing optimal training programs,with the hope of helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The training-performance model used in the proposed optimal control framework is a conceptual extension of the Banister impulse-response model that describes the dynamics of performance,training load(served as the control variable),fitness(the overall positive effects on performance),and fatigue(the overall negative effects on performance).The objective functional of the proposed optimal control framework is to maximize the fitness and minimize the fatigue on the competition day with the goal of maximizing the performance on the competition day while minimizing the cumulative training load during the training course.The Forward-Backward Sweep Method is used to solve the proposed optimal control framework to obtain the optimal solutions of performance,training load,fitness,and fatigue.The simulation results show that the performance on the competition day is higher while the cumulative training load during the training course is lower with using optimal control theory than those without,successfully showing the feasibility and benefits of using the proposed optimal control framework to design optimal training programs for helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The present feasibility study lays the foundation of the combined use of optimal control theory and training-performance models to design personalized optimal training programs in real applications in athletic training and sports science for helping athletes achieve the best performances in competitions while prevent overtraining and the risk of overuse injuries.展开更多
The University of Arizona Center for Integrative Medicine （AzCIM） was founded in 1994 with a primary focus of educating physicians in integrative medicine （IM）. Twenty years later, IM has become an internationally...The University of Arizona Center for Integrative Medicine （AzCIM） was founded in 1994 with a primary focus of educating physicians in integrative medicine （IM）. Twenty years later, IM has become an internationally recognized movement in medicine. With 40% of United States＇ medical schools having membership in the Academic Consortium for Integrative Medicine and Health it is foreseeable that all medical students and residents will soon receive training in the principles and practices of IM. The AzCIM has the broadest range and depth of IM educational programs and has had a major influence on integrative medical education in the United States. This review describes the fellowship, residency and medical student programs at AzCIM as well as other significant national drivers of IM education; it also points out the challenges faced in developing IM initiatives. The field of IM has matured with new nationa board certification in IM requiring fellowship training. Allied health professional IM educational courses, as well as integrative health coaching, assure that all members of the health care team can receive training. This review describes the evolution of IM education and will be helpful to academic centers, health care institutions, and countries seeking to introduce IM initiatives.展开更多
For the coach industry,rapid modeling and efficient optimization methods are desirable for structure modeling and optimization based on simplified structures,especially for use early in the concept phase and with capa...For the coach industry,rapid modeling and efficient optimization methods are desirable for structure modeling and optimization based on simplified structures,especially for use early in the concept phase and with capabilities of accurately expressing the mechanical properties of structure and with flexible section forms.However,the present dimension-based methods cannot easily meet these requirements.To achieve these goals,the property-based modeling(PBM)beam modeling method is studied based on the PBM theory and in conjunction with the characteristics of coach structure of taking beam as the main component.For a beam component of concrete length,its mechanical characteristics are primarily affected by the section properties.Four section parameters are adopted to describe the mechanical properties of a beam,including the section area,the principal moments of inertia about the two principal axles,and the torsion constant of the section.Based on the equivalent stiffness strategy,expressions for the above section parameters are derived,and the PBM beam element is implemented in HyperMesh software.A case is realized using this method,in which the structure of a passenger coach is simplified.The model precision is validated by comparing the basic performance of the total structure with that of the original structure,including the bending and torsion stiffness and the first-order bending and torsional modal frequencies.Sensitivity analysis is conducted to choose design variables.The optimal Latin hypercube experiment design is adopted to sample the test points,and polynomial response surfaces are used to fit these points.To improve the bending and torsion stiffness and the first-order torsional frequency and taking the allowable maximum stresses of the braking and left turning conditions as constraints,the multi-objective optimization of the structure is conducted using the NSGA-II genetic algorithm on the ISIGHT platform.The result of the Pareto solution set is acquired,and the selection strategy of the final solution is discussed.The case study demonstrates that the mechanical performances of the structure can be well-modeled and simulated by PBM beam.Because of the merits of fewer parameters and convenience of use,this method is suitable to be applied in the concept stage.Another merit is that the optimization results are the requirements for the mechanical performance of the beam section instead of those of the shape and dimensions,bringing flexibility to the succeeding design.展开更多
基金supported by the Irish Research Council(Grant No.GOIPG/2014/914)
文摘Purpose: This study aims to identify the concussion-related training and education needs of Gaelic Athletic Association(GAA) coaches in Ireland,as well as the preferred method of concussion education delivery.Methods: We used a self-report questionnaire to collect data from a convenience sample of 108 GAA coaches in Ireland. Data were captured on(1) informational needs and desires,(2) preferred methods of delivery, and(3) concussion practices and procedures. Questionnaires were completed electronically from June 3 rd–September 29 th, 2015.Results: Coaches indicated that they were most interested in receiving information about the(1) signs and symptoms of concussion,(2) assessment of concussion, and(3) return-to-play guidelines. Over two-thirds of participants indicated that in-person training would be the most effective mode of delivery of concussion education for this population. Additionally, only 10% coaches reported that before the start of the season they talked to their athletes about concussion management and safety, and this was more common among coaches who reported being formally educated about concussion.Conclusion: Our findings reveal a disconnect between the concussion education needs and the education that is currently provided to GAA coaches, in terms of content and delivery modality. Our results suggest a need for a multifaceted approach to concussion education, tailored to the needs and learning preferences of the target population.
文摘Context and Objective: Hamstring strain is a common injury in football and it causes a significant amount of time lost from competition and training. Since poor flexibility is thought to predispose to muscle strain, stretching is routinely recommended during warm-up routines by coaches to prevent injuries. However, available evidence suggests that pre-exercise stretching (PES), especially static stretching, has no benefit on injury rates and may even reduce performance in explosive type activities. We designed this study to assess the attitudes, beliefs and practices of football coaches regarding stretching in the prevention of hamstring strains. Design: A cross-sectional survey. Setting: Mauritius Football Association (MFA). Participants: 26 football coaches registered with the MFA. Intervention: Questionnaires were distributed to football coaches of the MFA via sports officers. Questionnaires were then collected two weeks after distribution. Main Outcome Measures: Attitudes, beliefs and practices of football coaches regarding stretching in the prevention of ham-string strains. Results: MFA coaches held generally positive attitudes and beliefs towards stretching. 88% of coaches felt that PES is beneficial and 93% believed that PES prevents hamstring strains. The majority of coaches recommended stretching after warming up (81%) and after the training session (93%). 76% of coaches also advised stretching outside the training sessions. 96% of coaches used static stretching to stretch the hamstrings. The hamstrings were stretched on average for 4 times at each training session and the mean duration of a static stretch was 12 seconds. Conclusions: Nearly all coaches believed that PES prevents hamstring strains although evidence is limited. Some of the coaches’ beliefs and practices were not in line with current recommendations. Coaches reported that their stretching practices would be most likely influenced by scientific research. Thus there is an urgent need to devise awareness and training programmes in this area.
文摘Gymnasts are exposed to intense training,frequent competitions,controlled diets and high levels of psychological distress in youth age.These aspects can negatively affect athletic performance and have health consequences.Accordingly,if the coaches do not possess adequate knowledge and specific multi-disciplinary skills related to sports practice and health pedagogy,young athletes can be exposed to different health risks.The aim of this study is to investigate the knowledge and attitudes of coaches and identify any education needs to enhance or preserve the gymnasts’well-being.The sample is represented by 98 Italian rhythmic gymnastics coaches of different levels.The data were obtained by using structured and anonymous questionnaires with open and closed answers administered through interview.The aspects examined are related to nutrition,food supplements,overtraining syndrome,educational topics,gymnasts’hassles and trainings needs of coaches.Critical aspects that emerge from this study show the need for specific scientific training and support for coaches.This objective can be achieved by providing constant technical and scientific support,in order to make the coaches fully aware of their educational,pedagogical and long-term health responsibilities of their athletes.
文摘Coaches experience considerable stress and anxiety in their pursuit of both team and individual success. Although there has been an increase in research aimed at promoting and managing the mental health of student-athletes, the mental well-being of coaches remains underexplored. Research indicates that the mental health profiles of coaches are similar to those of elite athletes [1] and should receive comparable attention. The introduction of Name, Image, and Likeness (NIL) legislation, along with the rise of the Transfer Portal in collegiate athletics, has presented student-athletes with new and unexpected options, which also bring novel challenges to coaches and potentially impact elite-level coaches’ mental health. This manuscript will identify three categories of stressors—performance, organizational, and self-related—that affect elite men’s college basketball coaches, highlighting how NIL and the Transfer Portal exacerbate those stressors and their impact on coaches’ mental health.
基金This investigation was supported by the Ministry of Education and Science of Spain(DEP2009-10253)FPU Program of the Ministry of Education,Culture and Sports(FPU12/05606).
文摘The aim of this study was to analyse the rate and content of 10,430 messages,sent by 21 handball coaches in 21 matches,in relation to score and match phase.Three situations were defined as regards score:large victory,tight game,and large defeat;and four phases for match phase:part 1 and 2 of first half,and part 1 and 2 of second half.Message rates were calculated by dividing the number of messages sent at each level of score and match phase by the elapsed time.To calculate the content,messages were coded using Coach Analysis and Intervention System and percentages were calculated according to score and match phase.Chi-square analysis showed statistically significant differences for rate of messages by score(χ^(2)=211.06,df=2,sig<0.001),and match phase(χ^(2)=23.704,df=3;sig<0.001);and for percentage of content by score(χ^(2)=444.011,df=42,sig<0.001)and match phase(χ^(2)=201.706,df=63,sig<0.001).Results can help to establish guidelines to increase the quality of coaches’speech.
文摘China’s latest exportan overseas coaching legion,received lots of attention as well as understanding in Beijing 0n the evening of August 23, one day before the closing of the Beijing Olympics, the Chinese diving team was only one gold short of its dream. The last diving event was the men’s 10 meters platform. The Chinese audience was confident that their divers would secure this gold.
文摘Purpose It is well recognised that injury prevention training can reduce injury incidence,however current coach education pathways do not provide grass-root coaches with the knowledge and confidence to deliver such training to youth players.The aim of this study was to explore differences in knowledge,understanding,attitude and confidence to deliver such injury prevention training in three European countries.Methods A total of 269 grass-root soccer coaches from 3 European countries(Czech Republic,UK,Spain)were recruited for this study.A validated questionnaire exploring knowledge,understanding,attitude towards and confidence to deliver youth injury prevention training was completed prior to a 2 h workshop on injury prevention training.Differences between countries was examined using Bayesian factors to quantify the evidence for and against the hypothesis of independence(H0)by assuming a Poisson sampling scheme(as there was no a priori restriction on any cell count,nor on the grand total)(BF10 Poisson).Results Current knowledge,attitude and confidence to deliver injury prevention training to youth players was poor across all three European countries.Relatively few coaches were currently using injury prevention training in their coaching sessions(23%).There were some country specific differences for attitude towards injury prevention training and confidence to deliver injury training,with Spanish coaches reporting a more positive attitude and confidence to deliver such training.Significantly fewer coaches in the UK were using injury prevention training compared to coaches in Spain and the Czech Republic.Conclusion As coaches identified a need for coach education and few were delivering injury prevention training,there is a clear need to embed and implement this programme into the grassroots coaching framework of sports governing bodies to improve adoption,implementation and maintenance.
文摘Since it's made up of over 7,000 islands,the Philippines is not a nation with a well‑developed railway transportation.That means coach buses are going to be your best bet for getting city‑to‑city.There is a small light rail system called the Light Rail Transit(LRT)in the Metro Manila area,but it's desperately inefficient.
基金College Student Innovation Training Program Project(S202410225147)。
文摘To address the challenges of long commuting times,traffic congestion,high energy consumption,and emissions in inter-city travel,a new type of flying coach has been developed.This innovation aims to significantly shorten inter-city commuting times,enhance travel efficiency,and simultaneously reduce energy consumption and emissions.The flying coach integrates rail power supply technology,an intelligent operating system,and advanced new materials,comprising a catenary power supply guide rod and various sensor components.Based on analysis of traditional aircraft design principles,the research team simulated the design of the rail-powered flying coach using software such as AutoCAD and SolidWorks for three-dimensional modeling.The analysis results indicate that,compared to traditional aircraft and rail trains,the design of the new flying coach reduces its overall weight while maintaining carrying capacity,thereby improving commuting efficiency and environmental performance.This development lays a solid foundation for creating a greener,more efficient,and convenient inter-city transportation network.
基金funded by the National Science and Technology Council,grant number NSTC 113-2221-E-002-136-.
文摘In order to help athletes optimize their performances in competitions while prevent overtraining and the risk of overuse injuries,it is important to develop science-based strategies for optimally designing training programs.The purpose of the present study is to develop a novel method by the combined use of optimal control theory and a training-performance model for designing optimal training programs,with the hope of helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The training-performance model used in the proposed optimal control framework is a conceptual extension of the Banister impulse-response model that describes the dynamics of performance,training load(served as the control variable),fitness(the overall positive effects on performance),and fatigue(the overall negative effects on performance).The objective functional of the proposed optimal control framework is to maximize the fitness and minimize the fatigue on the competition day with the goal of maximizing the performance on the competition day while minimizing the cumulative training load during the training course.The Forward-Backward Sweep Method is used to solve the proposed optimal control framework to obtain the optimal solutions of performance,training load,fitness,and fatigue.The simulation results show that the performance on the competition day is higher while the cumulative training load during the training course is lower with using optimal control theory than those without,successfully showing the feasibility and benefits of using the proposed optimal control framework to design optimal training programs for helping athletes achieve the best performance exactly on the competition day while properly manage training load during the training course for preventing overtraining.The present feasibility study lays the foundation of the combined use of optimal control theory and training-performance models to design personalized optimal training programs in real applications in athletic training and sports science for helping athletes achieve the best performances in competitions while prevent overtraining and the risk of overuse injuries.
文摘The University of Arizona Center for Integrative Medicine （AzCIM） was founded in 1994 with a primary focus of educating physicians in integrative medicine （IM）. Twenty years later, IM has become an internationally recognized movement in medicine. With 40% of United States＇ medical schools having membership in the Academic Consortium for Integrative Medicine and Health it is foreseeable that all medical students and residents will soon receive training in the principles and practices of IM. The AzCIM has the broadest range and depth of IM educational programs and has had a major influence on integrative medical education in the United States. This review describes the fellowship, residency and medical student programs at AzCIM as well as other significant national drivers of IM education; it also points out the challenges faced in developing IM initiatives. The field of IM has matured with new nationa board certification in IM requiring fellowship training. Allied health professional IM educational courses, as well as integrative health coaching, assure that all members of the health care team can receive training. This review describes the evolution of IM education and will be helpful to academic centers, health care institutions, and countries seeking to introduce IM initiatives.
文摘For the coach industry,rapid modeling and efficient optimization methods are desirable for structure modeling and optimization based on simplified structures,especially for use early in the concept phase and with capabilities of accurately expressing the mechanical properties of structure and with flexible section forms.However,the present dimension-based methods cannot easily meet these requirements.To achieve these goals,the property-based modeling(PBM)beam modeling method is studied based on the PBM theory and in conjunction with the characteristics of coach structure of taking beam as the main component.For a beam component of concrete length,its mechanical characteristics are primarily affected by the section properties.Four section parameters are adopted to describe the mechanical properties of a beam,including the section area,the principal moments of inertia about the two principal axles,and the torsion constant of the section.Based on the equivalent stiffness strategy,expressions for the above section parameters are derived,and the PBM beam element is implemented in HyperMesh software.A case is realized using this method,in which the structure of a passenger coach is simplified.The model precision is validated by comparing the basic performance of the total structure with that of the original structure,including the bending and torsion stiffness and the first-order bending and torsional modal frequencies.Sensitivity analysis is conducted to choose design variables.The optimal Latin hypercube experiment design is adopted to sample the test points,and polynomial response surfaces are used to fit these points.To improve the bending and torsion stiffness and the first-order torsional frequency and taking the allowable maximum stresses of the braking and left turning conditions as constraints,the multi-objective optimization of the structure is conducted using the NSGA-II genetic algorithm on the ISIGHT platform.The result of the Pareto solution set is acquired,and the selection strategy of the final solution is discussed.The case study demonstrates that the mechanical performances of the structure can be well-modeled and simulated by PBM beam.Because of the merits of fewer parameters and convenience of use,this method is suitable to be applied in the concept stage.Another merit is that the optimization results are the requirements for the mechanical performance of the beam section instead of those of the shape and dimensions,bringing flexibility to the succeeding design.
