46 results on '"Mercier, Kevin"'
Search Results
2. The Association of Perceived Mattering and Emotions with Physical Educator Teacher Resilience
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Simonton, Kelly L., Mercier, Kevin, Richards, K. Andrew R., and Gaudreault, Karen L.
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The purpose of this study was to examine the relationships among teachers' perceived mattering, their identified emotional experiences while teaching, and their self-reported teacher resilience. Perceptions of teacher mattering and teacher emotions were examined as characteristics that may directly and indirectly be associated with teacher resilience. Physical educators (N = 379; M[subscript age] = 42.44; 54% male; 46% female) participated in a cross-sectional survey. The participants had been teaching physical education (PE) for an average of 16 years, with approximately 68% holding an advanced degree. Confirmatory factor analysis and structural equation modeling were used to explore hypothesized relationships among the following variables: perceived mattering (i.e. physical education mattering, teacher mattering), teacher emotions (i.e. enjoyment, anger, anxiety), and teacher resilience. Results showed that perceptions of physical education mattering were related to perceived teacher mattering. Subsequently, teacher mattering was associated with teacher enjoyment and anxiety, which were then linked positively and negatively to resilience, respectively. No direct relationship was identified between mattering and resilience, but indirect relations via emotions were found. Thus, emotions appeared to mediate the perceived mattering-resilience relationship. Both environmental and personal variables should be considered when studying teachers' psychosocial skills in navigating workplace contexts. Enjoyment may buffer marginality beliefs and enhance resilience in day-to-day teaching. The characteristics of having or developing resilience appear to be founded somewhat in emotional experiences which, in turn, have shown strong links with actions, beliefs, and behaviors among teachers.
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- 2023
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3. Middle School Students' Attitudes toward Physical Activity and Physical Education, Intentions, and Physical Activity Behavior
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Mercier, Kevin, Simonton, Kelly, Centeio, Erin, Barcelona, Jeanne, and Garn, Alex
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Schools are focusing more on promoting physical activity (PA) before, during, and after the school day, to combat the risk factors associated with sedentary behaviors. Since attitudes impact decisions to be physically active, identifying how PA attitudes relate to established attitudes toward physical education (PE), as well as PA intentions and behaviors are important--and thus the focus of this study. Middle school students (N = 948; 45% female) completed PA behavior, PA intention, and PA and PE attitude surveys. Findings provided a better understanding of attitude theory with the identification of relationships between PA attitudes and PE attitudes, behavioral intention, and behavior. Multiple regression model results showed significant relationships between positive PA attitudes, negative PA attitudes, and PE attitudes with behavioral intention, and self-reported PA behavior. Differences between positive and negative PA attitudes were identified with positive PA attitudes most predicting intention. The results provide guidance for developing learning experiences aimed at promoting attitudes toward PA.
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- 2023
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4. The Success and Struggles of Physical Education Teachers While Teaching Online during the COVID-19 Pandemic
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Centeio, Erin, Mercier, Kevin, Garn, Alex, Erwin, Heather, Marttinen, Risto, and Foley, John
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The purpose of this study was to investigate physical education teachers' perceptions of implementing online physical education during the COVID-19 pandemic as well as to explore their needs with regard to support for future teaching experiences. A total of 4,302 teachers completed four open-ended questions as part of a larger survey. Deductive and inductive qualitative analysis led to three themes: (a) Teachers' Proud Moments, (b) Help! So Many Obstacles, and (c) Future Challenges. Teachers stated many successes and challenges that they experienced through the COVID-19 pandemic. Many items specifically focused on use and access to technology, student participation, and meeting students' needs in various ways. Results can provide guidance for how to address the essential components of physical education in the online environment. In addition, results may provide insight to those who educate, train, and prepare teachers to teach in a virtual and/or physically distanced environment.
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- 2021
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5. Physical Education Teachers' Experiences with Remote Instruction during the Initial Phase of the COVID-19 Pandemic
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Mercier, Kevin, Centeio, Erin, Garn, Alex, Erwin, Heather, Marttinen, Risto, and Foley, John
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This study investigated physical education (PE) teachers' experiences with remote instruction in the United States during the initial outbreak of COVID-19. PE teachers (n = 4,362) from all 50 states completed a survey identifying their experiences with remote instruction in May, 2020. Survey responses were analyzed by geographic region, district type, and school level. Teachers reported having students submit assignments (51% yes), using video instruction (37% yes), being less effective when instructing remotely (20% yes), and emphasizing student outcomes focused on health-related fitness (32% yes), and physical activity value/enjoyment (43% yes). Access to technology (40% yes) and required student assignments (43% yes) were lowest among teachers from the South. Rural teachers reported the least access to technology (37% yes) and rated themselves as least effective (24% yes). Secondary level teachers reported the highest percentage of required assignments (84% yes). Teachers' responses identify unique challenges to delivering equitable and effective remote PE instruction.
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- 2021
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6. Development of Youth Physical Activity Attitude Scale (YPAAS) for Elementary and Middle School Students
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Simonton, Kelly, Mercier, Kevin, Centeio, Erin, Barcelona, Jeanne, Phillips, Sharon, and Garn, Alex C.
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The purpose of this study was to develop the Youth Physical Activity Attitude Scale (YPAAS). Questions were developed using dual-component (affective-cognitive, positive-negative) beliefs framework. Content validity was established with expert panel review. Two samples of 4th-8th grade students (51% Female; 9-14 years) completed the YPAAS (sample 1, n= 3,188; sample 2n= 679). Exploratory and confirmatory factor analyses and structural equation modeling were used to examine the construct and criterion validity of the YPASS. Results indicated a 12-item measure with positive and negative attitude dimensions. Students in upper-grade levels reported stronger negative attitudes toward physical activity compared to students in lower grades. The YPASS produced invariant scores for boys and girls. Structural equation modeling revealed that positive attitudes related to both physical activity intentions and behaviors. Overall, scores from the YPAAS were shown to be valid and reliable for capturing youths' positive and negative attitudes toward physical activity.
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- 2021
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7. Middle School Students' Perceptions of Physical Education: A Qualitative Look
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Phillips, Sharon R., Marttinen, Risto, Mercier, Kevin, and Gibbone, Anne
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Purpose: Existing research suggests that students' attitudes toward physical education are positive through Grade 5, but become less positive as grade levels increase; this research is, however, missing student voice. The purpose of this study was to further understand why students' attitudes have been shown to decrease. Methods: Twenty-six focus group interviews (students N = 65) were conducted over 2 years to discover what was influencing attitudes from fifth to eighth grade. Results: Three themes emerged: (a) curriculum leads to decreases in student attitudes (subthemes repetitive and boring, an overemphasis on competition, and fitness testing activities--what's the purpose and why am I on display?), (b) social factors impact attitude: sweating and changing, and (c) physical education assumptions, the easy "A" (subthemes: perceptions of physical education teachers and the easy "A"). Conclusion: Allowing students to explain the reasons for decreases in attitudes contributes to improving the teaching and learning process.
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- 2021
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8. Investigating the Effects of Federal Funding on Students' Attitudes toward Physical Education
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Mercier, Kevin, Donovan, Corinne, and Gibbone, Anne
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Students' attitudes toward physical education (PE) affect decisions to be physically active, are affected by the teacher and the curriculum, and become less positive as children get older. Federal funding has been granted to improve physical education programs, yet it is unknown how this funding affects attitudes and decisions to remain active. Attitudes toward PE of students from three schools that received large federal grants (n = 2,962) were compared to attitudes of students from two schools that did not receive funding (n = 3,252) for 3 years. Federal funding does not appear to slow decreases in students' attitudes. Significant differences between groups only appeared in fourth and fifth grade, with small effect sizes. Though funding added equipment, curricula, professional development, and technology to PE programs, more than funding--instead a focus on teaching and implementation--is likely needed to improve students' attitudes toward PE.
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- 2020
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9. Do Fitness Test Performances Predict Students' Attitudes and Emotions toward Physical Education?
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Simonton, Kelly L., Mercier, Kevin, and Garn, Alex C.
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Background: The use of fitness tests in physical education (PE) receives extensive scrutiny and represents one of the most fiercely debated topics in PE research. Fitness test proponents often provide unwavering support citing their positive long-term benefits while critics underscore the corrosive long-term pitfalls associated with their use in PE. In many instances, both proponents and critics alike make these arguments with limited evidence to support their claims. Recently, critics have also highlighted the gendered nature of fitness tests, reporting that overt characteristics of these tests and their implementation create covert messages that reduce girls' motivation toward PE. Therefore, there is a clear need to gather evidence concerning the effects that fitness tests have on students' subjective experiences in PE. Purpose: The purposes of this study were twofold. First, we examine relationships between middle school students' fitness test performances and their future attitudes and emotions toward PE. Second, we investigate how these relationships vary for girls and boys. Method: A total of 273 middle school students (6th-8th grade; Male = 52%, Female = 48%) completed Fitnessgram™ battery of tests. Two weeks later, students completed two previously validated surveys about: a) their attitudes, and b) their discreet emotions (enjoyment, boredom, and anger) toward PE. First, structural equation modeling (SEM) was used to evaluate relationships for the entire sample. Once this baseline model was established, multi-group SEM identified similarities and differences in the pattern of relationships between girls and boys. Results: Findings revealed that better PACER performance predicted lower reports of future anger toward PE for both girls and boys. Conversely, increased performance on the curl-up test predicted higher rates of anger and lower rates of enjoyment toward PE. Increased PACER performance also predicted favorable attitudes for boys but not girls while increased sit-and-reach performance predicted favorable attitudes for girls but not boys. It should be noted, however, that fitness test performances explained limited amounts of variance in these outcomes, especially for girls. Conclusions: Unlike the common arguments about the valuable or harmful effects of fitness testing, our results suggested these tests had limited associations with students' future attitudes and emotions toward PE. Overall, we remain pessimistic about the use of fitness tests in PE because these PE teachers implemented fitness tests in isolation of the broader PE curriculum. Scores were neither shared with parents/guardians nor used to help students learn about their fitness. Students did not compare their results to previous tests and, to our knowledge, scores were not used for any large-scale surveillance purposes. It remains unclear how fitness test performances relate to student attitudes and emotions toward PE when implemented in a comprehensive and connected manner within the broader curriculum.
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- 2019
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10. Most Physically Educated Contest
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Mercier, Kevin and Howard, Thomas
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It is seldom that the accomplishments of secondary physical education students are celebrated. The Most Physically Educated Contest was developed to allow students from several school districts to gather for appropriate competition and to display the characteristics of physical literacy attained from participation in high-quality physical education programs. The purpose of this article is to share with readers the process of developing, organizing and executing a Most Physically Educated Contest so that others can replicate the event in their own setting. Students participated in the following events, with assessments aligned with the National Standards: (1) written essay, (2) PACER test, (3) push-up assessment, (4) badminton task, and (5) basketball task. All of the steps from initial planning to awards, including keys to success, schedule of events, and the awards ceremony, are presented.
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- 2018
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11. Experiences of Teacher Evaluation Systems on High School Physical Education Programs
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Phillips, Sharon R., Mercier, Kevin, and Doolittle, Sarah
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Primary objective: Teacher evaluation is being revamped by policy-makers. The marginalized status of physical education has protected this subject area from reform for many decades, but in our current era of system-wide, data-based decision-making, physical education is no longer immune. Standardized and local testing, together with structured observation measures, are swiftly being mandated in the USA as required elements of teacher evaluation systems in an effort to improve school programs and student achievement. The purpose of this investigation was to document how this reform was initiated and the experiences of teachers, students and administrators, from three high school physical education programs, during initiation of this reform. Documenting how physical education programs respond to such reforms develops our understanding of top-down reform efforts and helps to identify conditions under which such reforms have the intended effect on physical education teachers and student learning in physical education. Theoretical Framework: Fullan's three phases of school change has been used to analyze and guide school change efforts in several subject areas including physical education. The phases are initiation, implementation and institutionalization. This study is situated primarily within the first phase of school change, the initiation phase. Methods and Procedures: This study took place over a 21-month period in 3 suburban school districts in a northeast metropolitan area of the USA. Interviews with district physical education administrators, high school physical education teachers and students were conducted. Field notes of physical education classes, informal interviews and related artifacts including pre- and post-physical education assessments were collected. To ensure trustworthiness, several steps were taken including member checks, triangulation and peer review. The data were analyzed to find common themes and patterns using the constant comparative method. Results: Several themes emerged: (1) changes in curriculum and assessment; (2) effect on administrators; (3) stakeholder apathy and (4) department collaboration. Conclusion: Changes, although minor, did take place in the wake of this top-down teacher reform; however, additional research needs to be completed to determine whether or not these changes are meaningful or long lasting.
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- 2017
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12. 'Fitness Assessment': Recommendations for an Enjoyable Student Experience
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Phillips, Sharon R., Marttinen, Risto, and Mercier, Kevin
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Fitness assessment can be an important and useful component of physical education. This article discusses how to avoid the pitfalls that lead to negative student experiences with fitness assessment and presents research-based suggestions for creating a positive experience for all students. A section to help teachers understand how to use fitness assessment properly within the physical education program is included, with examples of lesson ideas and resources aligned with each recommendation. It is hoped that teachers will use this information to help students to gain the benefits of participating in fitness assessment as part of their physical education program.
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- 2017
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13. Educating Future Leaders of the Sport-Based Youth Development Field
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Whitley, Meredith A., McGarry, Jennifer Bruening, Martinek, Thomas, Mercier, Kevin, and Quinlan, Melissa
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In recent years, a substantial surge has occurred in the number of initiatives, events and organizations focused on using sport as a tool for development, peacebuilding and humanitarian efforts. This has created a growing need for educated leaders in the sport-based youth development field as the job market in this field continues to expand. The purpose of this article is to describe three academic programs currently preparing undergraduate and graduate students to succeed in leadership positions within sport-based youth development organizations. It explores how these academic programs are responding to the emerging job market and describes the courses and field-based experiences that provide students with the knowledge, skills and experiences to lead this growing field. The conclusion explores the strengths of these academic programs and the challenges they have faced, with a particular focus on information that may be beneficial to administrators, educators and practitioners.
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- 2017
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14. Three-Year Study of Students' Attitudes toward Physical Education: Grades 4-8
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Mercier, Kevin, Donovan, Corinne, Gibbone, Anne, and Rozga, Kimberly
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Purpose: A relationship exists between attitudes toward physical education and future physical activity. The purpose of this study was to examine changes in attitude toward physical education as students progressed from upper elementary school (Grade 4) through middle school (Grade 8). Method: Three cohorts of students (Cohort 1, Grades 4-6, n = 96; Cohort 2, Grades 5-7, n = 71; and Cohort 3, Grades 6-8, n = 73) were each followed for 3 years to examine changes in attitudes toward physical education. Results: After an initial increase from Grade 4 to Grade 5, a significant decrease was observed from Grades 5 to 8 in students' positive attitudes toward physical education, with a faster rate of change for girls than boys. Conclusion: This longitudinal study provides further insights regarding the attitudes of students as they progress from Grade 4 to Grade 8 and expands on previous findings identifying decreasing positive attitudes toward physical education as students age, particularly for girls. The results provide evidence to support targeted interventions.
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- 2017
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15. Investigating Attitudes toward Physical Education: Validation across Two Instruments
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Donovan, Corinne Baron, Mercier, Kevin, and Phillips, Sharon R.
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The Centers for Disease Control have suggested that physical education plays a role in promoting healthy lifestyles. Prior research suggests a link between attitudes toward physical education and physical activity outside school. The current study provides additional evidence of construct validity through a validation across two instruments measuring attitudes toward physical education by investigating their psychometric properties with a sample of 6th grade students (N = 377). Confirmatory factor analysis results indicate that the four-factor model fit the data well for both instruments based on fit indices, and a multitrait-multimethod analysis provides evidence of convergent and discriminant validity. Cross validation of these instruments permits longitudinal investigations on the role of attitudes toward physical education and their impact on physical activity.
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- 2015
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16. Believe in You student empowerment program: A pilot study
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Centeio, Erin E., primary, Barcelona, Jeanne M., additional, Mercier, Kevin, additional, Hart, Aaron, additional, and Foley, John T., additional
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- 2023
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17. Teaching for physical literacy: Implications to instructional design and PETE
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Silverman, Stephen and Mercier, Kevin
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- 2015
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18. High School Students' Attitudes toward Fitness Testing
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Mercier, Kevin and Silverman, Stephen
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The purpose of this study was to investigate the attitudes of high school students toward fitness testing. An instrument containing 18 items and four factors measuring student's attitudes toward fitness testing: cognitive, affect-enjoyment, affect-feelings, and affect-teacher was completed by 524 boys and 675 girls (N = 1199). MANOVA indicated significant differences among the dependent variables for grade and gender. A stepwise discriminant function analysis (DFA) indicated affect-feelings then affect-enjoyment as variables that predicted these differences. Follow-up tests indicated that gender, and not grade, was the cause of the significant affect-feelings differences. MANOVA for fitness test types and the follow-up DFA indicated that students who completed the FitnessGram test had significantly higher cognitive attitudes than those who completed the President's Challenge. The results suggest that student gender and the type of fitness test impact and lead to differences in attitudes.
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- 2014
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19. Summative Assessments: How We Improved Our High School Physical Education Program
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Mercier, Kevin and Iacovelli, Tracy
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Physical education classes at the authors' high school expose students to a variety of activities that are specifically geared toward their interests. The teachers and students also assess learning with the goal of attaining physical education standards including skills, strategies, rules, and personal/social responsibility. Seven years ago this was very different. This article summarizes the changes that took place in this program, beginning with the implementation of summative assessments.
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- 2014
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20. Middle School Assessments that Contribute to Literacy Goals
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Mercier, Kevin, Whitley, Meredith A., and Manson, Mara
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Assessment in physical education is not new. What is new is a national focus on teacher evaluation systems that include the use of student achievement scores from administered assessments. An additional educational focus is on the implementation of Common Core Learning Standards in all subject areas, including physical education. Physical educators are now being charged with implementing literacy concepts throughout their curricula. Although many effective physical educators have incorporated literacy concepts into their curricula for decades, recent reform efforts have placed the added expectation of documenting student learning in physical education. This article presents examples of field-tested middle school assessments that could be used in teacher evaluation systems to show student learning. The assessments presented can also be used as viable, realistic, and authentic evaluations in physical education that contribute to literacy goals associated with the Common Core Learning Standards.
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- 2014
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21. Validation of an Instrument to Measure High School Students' Attitudes toward Fitness Testing
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Mercier, Kevin and Silverman, Stephen
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Purpose: The purpose of this investigation was to develop an instrument that has scores that are valid and reliable for measuring students' attitudes toward fitness testing. Method: The method involved the following steps: (a) an elicitation study, (b) item development, (c) a pilot study, and (d) a validation study. The pilot study included 427 student-completed instruments from 3 schools. Pilot study data analyses were conducted resulting in a proposed model for the final study. Participants for the final study were 1,199 students (524 boys and 675 girls) from 13 schools. Thirty-six experts in physical education pedagogy were the participants of the content validity study. Results: The data fit a model with 4 factors: cognitive, affective-enjoyment, affective-feelings, and affective-teacher. Fit statistics from the confirmatory factor analysis indicated an overall good fit of the data to this model. Goodness of Fit Index (GFI), GFI Adjusted for Degree of Freedom, root mean square error of approximation, Bentler's Comparative Fit Index, and Bentler & Bonett's Normed Fit Index scores were 0.892, 0.862, 0.080, 0.920, and 0.910, respectively. The Guttman-Cronbach alpha reliability coefficients for the 4 factors and overall model were: cognitive (a = 0.919), affective-enjoyment (a = 0.887), affective-feelings (a = 0.865), affective-teacher (a = 0.801), and overall (a = 0.902). Conclusion: Scores from this instrument indicate that we can measure students' attitudes toward fitness testing well and can therefore permit further examination into the role these attitudes play in future physical activity.
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- 2014
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22. Accomplishing PETE Learning Standards and Program Accreditation through Teacher Candidates' Technology-Based Service Learning Projects
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Gibbone, Anne and Mercier, Kevin
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Teacher candidates' use of technology is a component of physical education teacher education (PETE) program learning goals and accreditation standards. The methods presented in this article can help teacher candidates to learn about and apply technology as an instructional tool prior to and during field or clinical experiences. The goal in developing successful technology-based service learning is to systematically guide candidates in their pursuit of pedagogically appropriate and meaningful projects, such as web page construction and the use of heart rate monitors, pedometers, mobile apps, active gaming, and digital video. The end product results in a contribution that will flourish at the school site. The purpose of this article is to provide examples of field-tested technology-based service learning projects that have been used to meet both PETE program goals and benchmarks for accreditation.
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- 2014
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23. Assessing Student Achievement in Physical Education for Teacher Evaluation
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Mercier, Kevin and Doolittle, Sarah
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While many teachers continue to ignore the practice of assessing student achievement in physical education, recent federal pressures to include student assessment data in teacher evaluation systems has shown that assessment of student outcomes is here to stay. Though there is a strong tradition of assessing teacher practice in physical education, standardized measures of student achievement and the requirement to show data on student learning in physical education are relatively new ideas. This article reviews issues about using student achievement data to evaluate physical education teachers. It also presents examples of assessments that could be used to document student achievement for the purpose of teacher evaluation. (Contains 1 table.)
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- 2013
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24. Teacher-led change in secondary school physical education
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Cameron, Jay, Mercier, Kevin, and Doolittle, Sarah
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High school students -- Education ,Physical education teachers -- Practice ,Teacher-student relationships -- Methods ,Education ,Sports and fitness - Abstract
How and why meaningful curriculum or program changes happen in physical education is important, but not well understood, especially at the secondary school level. In this longitudinal case study, we examined teacher-initiated changes in a high school physical education program. Data were collected through prolonged engagement over 5 years and included interviews with teachers and students, documents from the physical education department, field notes, survey responses, and presentation notes. A broad range of change forces, including a standards-based assessment program, was assessed using qualitative methods. Consistencies and inconsistencies between Fullan's theoretical framework on changes in education and what occurred in this physical education program are identified. Ways that change was aligned with Fullan's phases of change (Initiation, Implementation, and Institutionalization) were also considered. Results suggest that aspects of Fullan's framework are aligned with systematic changes in physical education. Teachers, as passionate, committed change agents, were essential for positive change. Elements of bottom-up and top-down educational reform were present in varying degrees. The effect of external change agents and funding, however, was noticeably absent., As a traditionally marginalized subject area, with little administrative attention, physical education has too often been allowed to languish behind other school reform efforts (Bechtel & O'Sullivan, 2007; Castelli & [...]
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- 2016
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25. Secondary School Students' Attitudes toward Fitness Testing
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Mercier, Kevin John
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The purpose of this investigation was to develop an instrument that has scores that are valid and reliable for measuring students' attitudes toward fitness testing. A second purpose of the study was to determine the attitudes of secondary students toward fitness testing. A review of literature, an elicitation study, and a pilot study were conducted. The pilot study included 427 student completed instruments from three schools. Pilot study data analyses were conducted resulting in a proposed model for the final study. Participants for the final study were 1199 students from 13 schools which consisted of 524 boys and 675 girls. The data fit a four factor model for measuring secondary school students' attitudes toward fitness testing with the following four factors: cognitive, affective-enjoyment, affective-feelings, and affective-teacher. The fit statistics from the CFA indicated an overall good fit of the data to this model. GFI, AGFI, RMSEA, Bentler's CFI, and Bentler & Bonett's NFI scores were 0.892, 0.862, 0.080, 0.920, and 0.910, respectively. The G-C alpha reliability coefficient for the entire model was 0.902. The four factors and their reliability scores were: cognitive ([alpha] = 0.919), affective-enjoyment ([alpha] = 0.887), affective-feelings ([alpha] = 0.865), and affective-teacher ([alpha] = 0.801). Secondary school students had an overall neutral to slightly positive attitude toward fitness testing (M = 3.11, s.d. = 0.71). Highest attitudes toward fitness testing were reported in the cognitive factor (M = 3.36, s.d. = 0.983) while the lowest attitudes occurred in the affective-enjoyment factor (M = 2.52, s.d. = 1.074). A MANOVA indicated significant differences for grade (Wilks' Lambda=0.950, F(12, 3143)=2.611, p less than 0.001) and gender (Wilks' Lambda=0.902, F(4, 1188)=2.611, p less than 0.01) with an interaction effect between grade and gender (Wilks' Lambda=0.974, F(12, 3143)=2.611, p=0.002). A stepwise DFA completed on the interaction means showed that the affect-feelings factor (Wilks' Lambda=0.927, F(7, 1191)=18.035, p less than 0.001) followed by the affect-enjoyment factor (Wilks' Lambda=0.904, F(7, 1191)=13.345, p less than 0.001) were the best predictors of these differences. Boys reported higher attitudes toward fitness testing (M = 3.28, s.d. = 0.74) than girls (M = 2.97, s.d. = 0.66). Boys overall attitude mean scores fell from 3.52 (s.d. = 0.70) in 9th grade to 3.15 (s.d. = 0.72) in 12th grade. Girls overall attitude scores dropped from 3.01 (s.d. = 0.58) in 9th grade to 2.86 (s.d. = 0.77) in 12th grade. A MANOVA indicated significant differences between FitnessGram and the President's Challenge fitness tests (Wilks' Lambda=0.985, F(4, 1194)=4.431, p=0.001). DFA indicated that the cognitive factor was the predictor of these differences (Wilks' Lambda=0.989, F(1, 1197)=13.597, p=0.001). Students' whose school administered the FitnessGram reported higher overall attitudes toward fitness testing (M = 3.14, s.d. 0.69) than students whose schools administered the President's Challenge fitness test (M = 3.04, s.d. = 0.74). [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]
- Published
- 2011
26. Comprehensive school health: teachers’ perceptions and implementation of classroom physical activity breaks in US schools
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Barcelona, Jeanne, primary, Centeio, Erin, additional, Phillips, Sharon, additional, Gleeson, Dara, additional, Mercier, Kevin, additional, Foley, John, additional, Simonton, Kelly, additional, and Garn, Alex, additional
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- 2022
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27. Success with Sport Education at a Secondary Level: Implementation and Examples from a Basketball Season
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Mercier, Kevin
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Based upon ten years of teaching and modifying the Sport Education Model at the high school level, this article summarizes how the author has had success in using the model to increase enthusiasm, student learning and quality participation in physical education. What started out as one teacher in the district testing the model with one class a decade ago, has evolved into a program with many teachers teaching multiple sections using the Sport Education Model. In this article, the author presents a brief background on the Sport Education Model, followed by an account of how to initiate implementation, including keys for success. Additionally, examples from a sport education high school basketball unit, which include how to use peer teaching and various assessments, are provided. (Contains 2 figures.)
- Published
- 2010
28. Middle school students’ attitudes toward physical activity and physical education, intentions, and physical activity behavior
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Mercier, Kevin, primary, Simonton, Kelly, additional, Centeio, Erin, additional, Barcelona, Jeanne, additional, and Garn, Alex, additional
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- 2022
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29. Expanding the Discrete Emotions in Physical Education Scale (DEPES): Evaluating Emotions With Behavior and Learning.
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Simonton, Kelly L., Garn, Alex C., and Mercier, Kevin J.
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SHAME ,AFFECT (Psychology) ,PHYSICAL education ,EMOTIONS ,STRUCTURAL equation modeling ,PHYSICAL education teachers ,SOCIAL skills ,EMOTION recognition - Abstract
Purpose: Students' affective experiences represent essential physical education (PE) learning outcomes. However, measuring these essential internal processes and understanding how they relate to behaviors has been difficult and limited thus far. The purpose of this study was to expand the Discrete Emotions in Physical Education Scale (DEPES) from the original three in-activity emotions (enjoyment, boredom, and anger) to include three additional outcome-related emotions (pride, shame, and relief). Method: Exploratory structural equation modeling (ESEM) analyses investigated the factor structure for the DEPES expansion with middle school (i.e., 6
th , 7th , & 8th grade) students from the United States (N = 495; Mage = 11.96 (SD =.98), 57% Female). Additionally, we examined predictive validity with relevant outcomes including perceived social competence, disruptive behavior, and multiple meta-cognitive knowledge beliefs (declarative, conditional, and procedural). Results: ESEM for the six emotions showed good model fit. Standardized factor loadings yielded strong primary loadings with minimal cross loading, suggesting discriminant validity for both in-activity and outcome-related emotions. Also, predictive validity of students' disruptive behavior (21%), social competence (40%), and metacognitive knowledge (40–57%), accounted for a significant portion of knowledge variance. Conclusion: The six emotions measured by the DEPES can provide clear and precise information on students' affective experiences in PE. Furthermore, measuring a variety of discrete emotions can help researchers/teachers capture unique motivational tendencies in students' behavior and knowledge. The evidence speaks to how limiting general positive/negative affect may be when trying to understand students' motivation/behaviors in PE. Overall, the DEPES can make valuable contributions to PE research and practice. [ABSTRACT FROM AUTHOR]- Published
- 2023
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30. Relationships and differences between goal orientations and emotional experiences of physical education teachers.
- Author
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Simonton, Kelly L., Mercier, Kevin, Richards, Kevin A.R., Gaudreault, Karen L., and Gray, Aimee
- Subjects
- *
TARGETS (Sports) , *PHYSICAL education , *DEMOGRAPHIC surveys , *SOCIAL goals , *SOCIAL change - Abstract
Despite the motivational impact of teacher goal orientations and emotions, there is limited investigation on those who experience marginalization, such as Physical Education teachers. The purpose of this study was to explore the relationships among and differences in Physical Education teacher goal orientations and emotions. Inservice Physical Education teachers (N = 364) from across the U.S. completed demographic, goal orientations, and emotions surveys. Analysis of variance and path analysis tests found that goal orientations and emotions differed significantly by context, instructional level, and years of experience. Aiding teachers in the development of mastery, approach, and social goal orientations can increase positive teacher experiences – improving their effectiveness and well-being. • First exploration of Physical Education teacher goal beliefs that include all five teacher goal orientations. • Physical Education teachers aligned and deviated from previous work on general subject classroom teachers. • Physical Education teachers goal orientation differ by context, grades taught, and years of teaching experiences. • Goal orientations beliefs were significantly related to teacher emotions (a representation of teacher well-being). • This studyhighlights the need for future research on the psychosocial aspects of teaching marginalized subject areas. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Expanding the Discrete Emotions in Physical Education Scale (DEPES): Evaluating Emotions With Behavior and Learning
- Author
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Simonton, Kelly L., primary, Garn, Alex C., additional, and Mercier, Kevin J., additional
- Published
- 2021
- Full Text
- View/download PDF
32. Youth Physical Activity Attitude Scale
- Author
-
Simonton, Kelly, primary, Mercier, Kevin, additional, Centeio, Erin, additional, Barcelona, Jeanne, additional, Phillips, Sharon, additional, and Garn, Alex C., additional
- Published
- 2021
- Full Text
- View/download PDF
33. Development of Youth Physical Activity Attitude Scale (YPAAS) for Elementary and Middle School Students
- Author
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Simonton, Kelly, primary, Mercier, Kevin, additional, Centeio, Erin, additional, Barcelona, Jeanne, additional, Phillips, Sharon, additional, and Garn, Alex C., additional
- Published
- 2020
- Full Text
- View/download PDF
34. Physically-based constitutive description of a commercial Al-Mg-Si alloy deformed under cold-warm working conditions
- Author
-
Le, Mercier, Kevin, Guerin, Jean-Dominique, Dubar, Mirentxu, Dubar, Laurent, Puchi-Cabrera, Eli, Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), and Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Centre National de la Recherche Scientifique (CNRS)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France)
- Subjects
Upsetting sliding test ,Stress/strain measurements ,[SPI]Engineering Sciences [physics] ,FE modeling ,Constitutive formulation ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,Aluminum alloys ,Plasticity methods - Abstract
International audience; The experimental and numerical modeling of cold forging operations conducted on commercial Al alloys requires a precise knowledge of the functional dependence of both flow stress and work-hardening rate on microstructure and deformation conditions. In order to contribute to the improvement of the finite element computer modeling of forming operations conducted on Al alloys, under cold-warm working conditions, an original and rational constitutive description, able to predict accurately both the flow stress and work-hardening rate of an AA6082-T6 Al alloy is proposed. The constitutive formulation has been developed on the basis of the Mechanical Threshold Stress (MTS) model and its applicability is limited to the deformation of the material under cold-warm working conditions, that is to say, in the temperature range of 298–423 K. A novel differential equation for the description of the continuous change in the work-hardening rate of the alloy has been developed, which allows the prediction of the changes in flow stress and work-hardening rate during deformation either under constant and variable temperature and strain rate conditions. The validation of the developed constitutive description has been accomplished by its implementation into a finite element (FE) model for the accurate prediction of the change in some local contact parameters, such as contact pressure, sliding velocity and interface temperature, during the friction test employed in the evaluation of friction conditions in metalworking, known as the Upsetting Sliding Test (UST).
- Published
- 2019
35. Étude du comportement tribologique de différents lubrifiants par le biais d’essais de compression-translation
- Author
-
Le Mercier, Kevin, Moreau, Philippe, Dubar, Laurent, TORCK, Kathleen, Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France)-Centre National de la Recherche Scientifique (CNRS)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC), and LAMIH, Université Polytechnique des Hauts-de-France
- Subjects
[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,[SPI.MECA] Engineering Sciences [physics]/Mechanics [physics.med-ph] - Published
- 2018
36. Relationship between Fitness Test Scores and Students' Attitudes
- Author
-
Mercier, Kevin, Gibbone, Anne, and Baron-Donovan, Corinne
- Published
- 2018
- Full Text
- View/download PDF
37. Quantification de l'usure adhésive en mise en forme à froid d'un alliage Al-Mg-Si
- Author
-
Le Mercier, Kevin, Dubar, Mirentxu, Mocellin, Katia, Dubois, André, Dubar, Laurent, Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Centre National de la Recherche Scientifique (CNRS)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Association Française de Mécanique
- Subjects
alliage aluminium ,"wear" ,usure adhésive ,"surface topography" ,mise en forme à froid ,"upsetting sliding test" ,[PHYS.MECA]Physics [physics]/Mechanics [physics] ,"6082 aluminium alloy" ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,analyse topographique ,"galling" - Abstract
Colloque avec actes et comité de lecture. Internationale.; International audience; Le forgeage à froid est un procédé de mise en forme permettant de réaliser des pièces aux formes proches de celles du produit fini avec une cadence de production élevée. La mise en forme du matériau est réalisée à température ambiante. Les pièces produites présentent des états de surface de bonne qualité et des tolérances géométriques précises. Cette qualité de production permet de réduire les coûts en économisant de la matière première et en limitant les étapes de parachèvement du produit. Les propriétés mécaniques des composants ainsi produits sont élevées grâce à l'écrouissage du matériau. Au cours des dernières années, l'utilisation de composants en alliage d'aluminium formé à froid a augmenté dans de nombreuses applications industrielles et particulièrement dans les applications automobiles et aéronautiques en vue d'alléger les structures. Ces derniers sont réputés pour leur compromis efficace entre leurs caractéristiques mécaniques, leur densité et leur résistance à la corrosion. Cependant, la mise en forme de ces alliages peut être limitée par les phénomènes d'usure adhésive. Le matériau adhère à la surface de l'outil puis il est endurci par oxydation, écrouissage ou raffinement de grain durant les différents cycles de mise en forme. La géométrie de l'outil et son état de surface sont alors altérés faisant apparaître des défauts sur les pièces produites. Ces phénomènes d'adhésion peuvent conduire au grippage du système compromettant ainsi la viabilité du procédé de mise en forme. Les travaux présentés dans cette communication sont issus d'une campagne expérimentale conduite dans le but d'analyser les mécanismes de collage au cours de la mise en forme à froid d'un alliage d'aluminium 6082. Cette recherche repose sur l'essai de compression-translation développé au LAMIH. Ce test permet de reproduire les conditions de contact locales au niveau de l'interface outil/pièce telles que la pression de contact, la vitesse de glissement ou la température interfaciale. Ces essais ont été menés sur des éprouvettes lubrifiées sur la gamme de vitesses de glissement comprise entre 20 et 200 mm.s-1 et à différents taux de déformation plastique. Les coefficients de frottement sont déterminés et les surfaces des outils sont analysées par le biais d'une approche originale combinant les analyses de composition par spectrométrie en énergie et la profilométrie optique. Des acquisitions de la topographie des outils sont obtenues à l'aide de l'outil MesRug 3D et d'un interféromètre en lumière blanche (Zygo NewViewTM 7300, Zygo Corp., USA). Dans un premier temps, des analyses EDS sont réalisées afin de déterminer la forme exacte de la zone altérée en discernant l'aluminium adhéré de l'acier à outil. Ensuite, une méthode spécifique de traitement des acquisitions topographiques est appliquée afin d'évaluer le volume de matière adhérée sur la surface des outils de chaque configuration d'essai. Cette méthode repose sur l'utilisation de la courbe de portance de la surface et d'un module de détection des ilôts. Finalement, le collage est observé sur chaque condition d'essai et deux régimes se distinguent en fonction de la vitesse de glissement. De plus, une forte corrélation entre les volumes de matière adhérée et le coefficient de frottement est mise en évidence. Ces conclusions montrent l'importance de la prise en compte d'un paramètre de frottement dans les modèles d'usure adhésive comme ceux fondés sur l'approche énergétique utilisant le travail des forces de frottement.
- Published
- 2017
38. Stratégie numérique et expérimentale pour la maîtrise de l'Usinage à Grande Vitesse
- Author
-
Watremez, Michel, Le, Mercier, Kevin, Sénécaut, Yannick, Dubar, Laurent, Association Française de Mécanique, Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), and Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Centre National de la Recherche Scientifique (CNRS)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France)
- Subjects
"tribologie" ,"formulation ALE" ,"lois de frottement" ,ALE ,modèle éléments finis ,"usinage grande vitesse" ,frottement ,comportement rhéologique ,[PHYS.MECA]Physics [physics]/Mechanics [physics] ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,usinage à grande vitesse - Abstract
Colloque avec actes et comité de lecture. Internationale.; International audience; L'usinage à grande vitesse présente de nombreux avantages par rapport à l'usinage conventionnel, mais reste soumis aux contraintes économiques et écologiques. L'optimisation des paramètres de coupe doit permettre d'accroître la productivité, de réduire l'usure des outils et d'assurer la qualité de la pièce usinée. Cette démarche nécessite de développer des approches numériques perspicaces de l'interface outil-copeau. Cela impose de déterminer précisément le comportement rhéologique des antagonistes et d'établir des modèles de frottement objectifs. En parallèle, des essais expérimentaux du procédé doivent permettre d'obtenir des données fiables pour garantir la pertinence des valeurs prédites par les modèles numériques. Dans les approches numériques pour l'usinage à grande vitesse, le comportement rhéologique des matériaux usinés est généralement décrit par une loi de Johnson Cook et le frottement à l'interface par un coefficient constant de type Coulomb. Il est ici proposé de déterminer une loi de frottement à paramètres multiples au moyen de deux tribomètres spécifiques. La méthodologie proposée utilise des modèles numériques des deux types d'essais tribologiques afin de déterminer une valeur de coefficient de frottement de type Coulomb associée à la pression locale, à la température et à la vitesse de glissement au sein du contact. La réalisation de nombreux essais permet d'estimer une loi de frottement dépendante des conditions locales dans le contact. L'implémentation de cette loi dans un modèle numérique permet donc d'affecter une valeur de frottement spécifique en fonction des variables locales de pression, de vitesse de glissement et de température au sein du contact outil-copeau. Des études ont montré que des phénomènes de recristallisation dynamique apparaissent lors de l'usinage dans l'interface outil-copeau. La loi de Johnson Cook ne permet pas de considérer ces phénomènes. Des modèles rhéologiques spécifiques basés sur la métallurgie sont introduits pour tenir compte de ces phénomènes de recristallisation dynamique. Deux modèles empiriques proposés par Kim [Kim03] et Lurdos [Lur08] sont étudiés. D'autres essais spécifiques sont réalisés sur un banc d'essai de coupe orthogonale afin de juger de l'objectivité de ces approches. Enfin, un modèle éléments finis de la coupe orthogonale à deux dimensions est développé avec le logiciel Abaqus Explicit en utilisant une formulation ALE (Arbitrary Lagrangian-Eulerian). Ce modèle peut alors prédire la formation des copeaux, les températures d'interface, les longueurs de contact et les forces de coupe. Il est finalement montré dans cette étude qu'il est nécessaire de prendre en compte une loi de frottement à paramètres multiples qui tient compte des pressions, de la température et des vitesses de glissement locales et d'intégrer une loi de comportement rhéologique à base métallurgique pour aboutir à une simulation numérique objective de l'usinage à grande vitesse.
- Published
- 2017
39. Stratégie numérique et expérimentale pour la maîtrise des dégradations des outillages en mise en forme à froid
- Author
-
Le Mercier, Kevin, Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Centre National de la Recherche Scientifique (CNRS)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Université de Valenciennes et du Hainaut-Cambresis, Mirentxu Dubar, and Katia Mocellin
- Subjects
Fem ,Mef ,Thermomechanical behavior ,Wear ,Usure ,Al-Mg-Si ,[SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] ,Aluminium ,Galling ,Comportement thermomécanique ,Collage ,Ust ,Ale - Abstract
Cold forming of aluminium alloys can be limited by a severe material transfer to the die surfaces, compromising the process viability. The purpose of this research work is to contribute to a broader understanding of the galling mechanisms which would further allow the optimisation of the forming processes of an Al-Mg-Si alloy. A methodology combining experimental and numerical approaches is introduced in order to build up a database of surface degradations indicators. The experimental approach is carried out by means of upsetting-sliding tests which reproduce a wide range of contact conditions experienced at the tool/workpiece interface during cold forming operations. To evaluate the amounts of adhered material on the tools of each test configuration, surface topography acquisitions are performed by optical profilometry and coupled to scanning electron microscope analyses. Axisymmetric compression tests are carried out by means of the GLEEBLE 3500 thermomechanical simulator to determine the deformation behaviour of the Al-Mg-Si alloy at high strains, in the temperature range of 298 to 423 K and strain rates of 0.1 and 1 s¡1. A constitutive model based on both the Mechanical Threshold Stress model and the analysis of the work-hardening rate is proposed and then implemented in a finite element code. A finite element simulation of the upsetting-sliding test, which is a thermomechanical analysis using the arbitrary lagrangian-eulerian formulation, is introduced. The local contact variables such as the contact pressure and the sliding velocity are evaluated through this simulation and allow a better understanding of the galling mechanisms observed experimentally. Finally, a post-processing program, which analyses the results of the finite element simulation and updates the tool shape according to the amount of adhered material determined experimentally, is developed. A wear model based on the friction work is introduced. This model is a good indicator of the galling tendency and allows a first approximation of this mechanism.; La mise en forme à froid des alliages d’aluminium peut être limitée par les transferts de matière sur la surface des outillages pouvant mener au grippage. L’objectif de ce travail de thèse est de contribuer à une meilleure compréhension de ces mécanismes pour permettre à terme d’optimiser les procédés de formage d’un alliage Al-Mg-Si. Une approche couplée expérimentale et numérique est développée afin d’alimenter une base de données d’indicateurs de dégradations des surfaces. L’approche expérimentale développée au cours de ces travaux repose sur l’utilisation de l’essai de compression-translation. Ce dispositif permet de reproduire une large gamme de conditions de contact rencontrées en mise en forme à froid. Une méthode d’analyse des surfaces reposant sur des mesures par profilométrie optique et des analyses au microscope électronique à balayage est développée afin d’évaluer le volume de matière adhérée sur les outils de chaque configuration d’essai. Le comportement rhéologique de l’alliage Al-Mg-Si est caractérisé à l’aide du simulateur thermomécanique GLEEBLE 3500 sur la gamme de températures de 298 à 423 K et à deux vitesses de déformation de 0,1 et 1 s-1. Un modèle de comportement physique reposant sur l’analyse du taux d’écrouissage et l’utilisation du modèle de la contrainte mécanique seuil est développé puis implémenté dans un logiciel éléments finis. Un modèle numérique de l’essai de caractérisation tribologique est développé. Il s’agit d’une analyse thermomécanique utilisant la formulation arbitrairement lagrangienne-eulérienne. Les données locales telles que la pression de contact et la vitesse de glissement calculées par ce modèle permettent de mieux comprendre les mécanismes de collage observés expérimentalement. Enfin, un programme de traitement des résultats numériques est développé afin de réaliser les modifications géométriques de la surface de l’outil en fonction du dépôt relevé expérimentalement. Un modèle d’usure basé sur le travail des forces de frottement est identifié. Ce dernier est un bon indicateur de la tendance au collage et permet une première approximation de ce mécanisme.
- Published
- 2017
40. Experimental and numerical strategy for the evaluation of the degradations mechanisms of cold forging tools
- Author
-
Le Mercier, Kevin, Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Centre National de la Recherche Scientifique (CNRS)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Université de Valenciennes et du Hainaut-Cambresis, Mirentxu Dubar, and Katia Mocellin
- Subjects
Fem ,Mef ,Thermomechanical behavior ,Wear ,Usure ,Al-Mg-Si ,[SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] ,Aluminium ,Galling ,Comportement thermomécanique ,Collage ,Ust ,Ale - Abstract
Cold forming of aluminium alloys can be limited by a severe material transfer to the die surfaces, compromising the process viability. The purpose of this research work is to contribute to a broader understanding of the galling mechanisms which would further allow the optimisation of the forming processes of an Al-Mg-Si alloy. A methodology combining experimental and numerical approaches is introduced in order to build up a database of surface degradations indicators. The experimental approach is carried out by means of upsetting-sliding tests which reproduce a wide range of contact conditions experienced at the tool/workpiece interface during cold forming operations. To evaluate the amounts of adhered material on the tools of each test configuration, surface topography acquisitions are performed by optical profilometry and coupled to scanning electron microscope analyses. Axisymmetric compression tests are carried out by means of the GLEEBLE 3500 thermomechanical simulator to determine the deformation behaviour of the Al-Mg-Si alloy at high strains, in the temperature range of 298 to 423 K and strain rates of 0.1 and 1 s¡1. A constitutive model based on both the Mechanical Threshold Stress model and the analysis of the work-hardening rate is proposed and then implemented in a finite element code. A finite element simulation of the upsetting-sliding test, which is a thermomechanical analysis using the arbitrary lagrangian-eulerian formulation, is introduced. The local contact variables such as the contact pressure and the sliding velocity are evaluated through this simulation and allow a better understanding of the galling mechanisms observed experimentally. Finally, a post-processing program, which analyses the results of the finite element simulation and updates the tool shape according to the amount of adhered material determined experimentally, is developed. A wear model based on the friction work is introduced. This model is a good indicator of the galling tendency and allows a first approximation of this mechanism.; La mise en forme à froid des alliages d’aluminium peut être limitée par les transferts de matière sur la surface des outillages pouvant mener au grippage. L’objectif de ce travail de thèse est de contribuer à une meilleure compréhension de ces mécanismes pour permettre à terme d’optimiser les procédés de formage d’un alliage Al-Mg-Si. Une approche couplée expérimentale et numérique est développée afin d’alimenter une base de données d’indicateurs de dégradations des surfaces. L’approche expérimentale développée au cours de ces travaux repose sur l’utilisation de l’essai de compression-translation. Ce dispositif permet de reproduire une large gamme de conditions de contact rencontrées en mise en forme à froid. Une méthode d’analyse des surfaces reposant sur des mesures par profilométrie optique et des analyses au microscope électronique à balayage est développée afin d’évaluer le volume de matière adhérée sur les outils de chaque configuration d’essai. Le comportement rhéologique de l’alliage Al-Mg-Si est caractérisé à l’aide du simulateur thermomécanique GLEEBLE 3500 sur la gamme de températures de 298 à 423 K et à deux vitesses de déformation de 0,1 et 1 s-1. Un modèle de comportement physique reposant sur l’analyse du taux d’écrouissage et l’utilisation du modèle de la contrainte mécanique seuil est développé puis implémenté dans un logiciel éléments finis. Un modèle numérique de l’essai de caractérisation tribologique est développé. Il s’agit d’une analyse thermomécanique utilisant la formulation arbitrairement lagrangienne-eulérienne. Les données locales telles que la pression de contact et la vitesse de glissement calculées par ce modèle permettent de mieux comprendre les mécanismes de collage observés expérimentalement. Enfin, un programme de traitement des résultats numériques est développé afin de réaliser les modifications géométriques de la surface de l’outil en fonction du dépôt relevé expérimentalement. Un modèle d’usure basé sur le travail des forces de frottement est identifié. Ce dernier est un bon indicateur de la tendance au collage et permet une première approximation de ce mécanisme.
- Published
- 2017
41. Experiences of teacher evaluation systems on high school physical education programs
- Author
-
Phillips, Sharon R., primary, Mercier, Kevin, additional, and Doolittle, Sarah, additional
- Published
- 2016
- Full Text
- View/download PDF
42. Thermo-mechanical behaviour of spheroidal graphite iron in the austenitic phase
- Author
-
Le Mercier, Kevin, Watremez, Michel, GUERIN, Jean-Daniel, FOUILLAUD, Laurence, Dubar, Laurent, Université de Valenciennes et du Hainaut-Cambrésis (UVHC), Mechanics surfaces and materials processing (MSMP), Arts et Métiers Sciences et Technologies, and HESAM Université (HESAM)-HESAM Université (HESAM)
- Subjects
[PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph] ,Thermo-mechanical behaviour ,Mécanique [Sciences de l'ingénieur] ,[SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] ,SG iron ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,Gleeble ,Mécanique: Mécanique des matériaux [Sciences de l'ingénieur] - Abstract
The main objective of this paper is to identify the thermo-mechanical behaviour at high temperature of the spheroidal graphite (SG) iron EN-GJS-700-2. In the rst instance, tensile and compression tests in austenitic phase are performed. These experiments are carried out using Gleeble 3500 system enabling a precise control on testing temperature and strain rate. Indeed, the e ects of these testing parameters on the SG iron behaviour are studied. Furthermore, a numerical inverse method is used to identify the Johnson-Cook constitutive model of this iron. Finally, post-mortem metallography of specimens is analyzed using optical microscopy.
- Published
- 2013
43. Dynamic Recrystallization of Spheroidal Graphite Iron during Hot Cutting Operations
- Author
-
Le Mercier, Kevin, primary, Watremez, Michel, additional, Fouilland-Paillé, Laurence, additional, and Dubar, Laurent, additional
- Published
- 2015
- Full Text
- View/download PDF
44. Evolution of Dynamic Recrystallization of AISI-1045 Steel under Critical Friction Conditions
- Author
-
Le Mercier, Kevin, primary, Watremez, Michel, additional, Brocail, Julien, additional, and Dubar, Laurent, additional
- Published
- 2014
- Full Text
- View/download PDF
45. Thermo-Mechanical Behaviour of Spheroidal Graphite Iron
- Author
-
Le Mercier, Kevin, primary, Watremez, Michel, additional, Fouilland, Laurence, additional, Guérin, Jean Dominique, additional, and Dubar, Laurent, additional
- Published
- 2014
- Full Text
- View/download PDF
46. CSPAPs in Urban Contexts
- Author
-
Doolittle, Sarah, primary, Rukavina, Paul, additional, and Mercier, Kevin, additional
- Published
- 2012
- Full Text
- View/download PDF
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