INTE 2015
THE MECHANICS OF RIGID BODIES IN MECHANICAL ENGINEERING
INTE 2015
and well understood basic principles for resolutions. Therefore, it is seen that “statics” and “dynamics” courses of rigid body’s mechanics are included in Education plans as two different obligatory basic engineering courses.
The students with that basic mechanics information in the first periods of engineering education learn strength course, solid body mechanic and fluid mechanics principles. They continue to use those basic information at also other engineering courses.
Mechanics of Rigid Bodies; Static Course
Static course that is introductory course to mechanic provide students to meet firstly to engineering term. Today many physical events that we observe frequently in daily life are tried to be approached with engineering formation view and tried to be transferred to the minds.
Static course included in course plans of Mechanical Engineering Departments of Turkish Universities in the scope of obligatory course of which 75% is shown in the second semester, 25% is shown in the third semester.
(Figure 1)
Figure 1. The semesters of Static course Figure 2. Static course hours weekly 70% of Static Course Engineering department Education plans are 3 hours in a week and 30% is 4 hours in a week. (Figure 2)
ACTS distribution at Static course varies between 4 and 9 credit. (Figure 3).
Figure 3. Static course ACTS Credits
Table 1. Static course weekly subjects Week Subjects
1 Introduction to Mechanics
2 Statics of Particles: Forces in Plane 3 Statics of Particles: Forces in Space 4 Rigid Bodies: Equivalent System of Forces 5 Rigid Bodies: Equivalent System of Forces
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6 Equilibrium of Rigid Bodies 7
Distributed Forces: Centroids and Centers of Gravity
8 First Midterm
9 Analysis of Structures
10 Forces in Beams and Cables
11 Friction
12 Equilibrium of Rigid Bodies Systems 13
Distributed Forces: Moment of Inertia of Masses
14 Second Midterm
15 Method of Virtual Work.
16 Final Exam
Static Course Learning Outcomes:
• Students shall gain knowledge about center of gravity and may solve related problems
• To gain knowledge about equilibrium of particles and rigid bodies
• Students shall gain knowledge about bonding and bonding forces
• Students shall gain specific information about equilibrium of structures (beams, trusses, frames, cables, machines)
Mechanics of Rigid Bodies; Dynamic Course
In engineering training, the teaching of dynamics in which behaviors of objects are studied generally comes after study of statics. The kinematics and kinetics that are the subdivisions of dynamics must be precisely learned in engineering to be able to get the powerful tool of analysis. Since the machines start at high speeds and at significant accelerations, the calculations required to be made according to the laws of dynamics instead of statics. The technological development of today on speed requires more implication of mechanical principles and especially the dynamics. Those principles are the basis for design and analysis of all moving objects, fixed structures that are subject to specific impact conditions, robotic equipment, automatic control systems, vehicles, pumps, turbines, cranes, and etc. (Meriam J. L., Kraige L.G., 2008).
It is necessary to learn dynamics to be able to understand, define, and make analysis of motions of objects with continuous transitions between physics and mathematics. The students, who could not understand the dynamics lectures, would face the problem of inadequacy to freely make these transitions.
Dynamic course is included in the third year in 65% rate, in the fourth year in 32.5% rate, in the fifth year in 2.5% rate in Mechanical Engineering Departments’ Education Plans(Figure 4). Weekly dynamic course dispersion varies from 2 to 5 hours (Figure 5).
Figure 4. The semesters of dynamic course Figure 5. Dynamic course hours weekly
INTE 2015
ACTS distribution at Dynamic course varies between 3 and 6 credit. (Figure 6).
Figure 6. Dynamic course ACTS Credits
Table 2. Dynamic course weekly subjects
Week Subjects
1 Introduction to Dynamics
2 Rectilinear Motion of Particles 3 Curvilinear Motion of Particles 4 Curvilinear Motion of Particles
5 Kinematics of Rigid Bodies
6 Kinematics of Rigid Bodies
7 Kinematics of Rigid Bodies
8 1st Midterm Exams
9
Kinetics of Particles; Force, Mass and Acceleration
10
Kinetics of Particles; Work, Energy and Momentum
11 Kinetics of System of Particles 12
Plane Motions of Rigid Bodies; Forces and Accelerations
13
Plane Motions of Rigid Bodies; Work and Energy
14 2nd Midterm Exam
15
Plane Motions of Rigid Bodies; Impulse and Momentum
16 Final Exam
When the distribution of dynamics lectures between weekly curriculums is studied, it is observed that there are some differences between schools in terms of their lecturing plans. The plan that is given above for lecturing during 15 weeks period has been found to be the more understandable by the students and it is observed that this plan saves time at lectures.
Dynamics Course Learning Outcomes:
• To be able to select and use an appropriate coordinate system to describe particle motion
• To be able to formulate dynamics models in accelerating frames
• To be able to identify and exploit situations in which integrated forms of the equations of motions, yielding conservation of momentum and/or energy for the particles and rigid bodies
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• To be able to formulate and analyze dynamics of bodies in plane motion RESULTS AND DISCUSSIONS
When instructional plans of Mechanical Engineering Departments in our country are examined, it is seen that statics course is studied mostly in the 2nd semester and dynamics course is studied in the next, 3rd semester.
Both courses are generally 3 hours in a week. It is proven to be appropriate to lecture statics and then dynamics courses just after the basic courses in the first semester.
Amendments are applied to Instructional Plans of the Mechanical Engineering Departments continuously, in terms of the number of courses and credit hours with a content of contemporary and international criteria.
Since providing the quality assurance in university education becomes imperative in a Europe where borders between countries removed, the success of universities and their diplomas are supposed to be recognized mutually in the European scale within the framework of the Bologna process.
In the context of the Bologna process, when course lesson plans of the Mechanical Engineering Departments of the Universities are compared, lesson titles, content and credits are not much different from each other. The mechanics of rigid bodies lessons also have the same situation.
Does Rigid Bodies Mechanics get the attention it deserves within Mechanical Engineering Education? If the answer is ‘YES’ then we could consider that there has been serious progress in these two fields. Firstly, we are educating students who are fully equipped to detect the mechanical problems which are part of his/her profession and analyze them from the engineering perspective. Secondly, the mathematical substructure and quick thinking skills needed for solving mechanical problems have been gained by the students.
REFERENCES
Beer F.P., Johnston E.R..( 2004). Vector Mechanics for Engineers: Statics, Seventh Edistion, ISBN 0-07- 230493-6, Mc Graw Hill.
Hibbeler R.C..(1978). Engineering Mechanics: Statics., 2nd Edition, ISBN 0-02-354020-6, New York.
Beer F.P., Johnston E.R..( 2004). Vector Mechanics for Engineers: Dynamics, Seventh Edistion, ISBN 0-07- 230492-8, Mc Graw Hill.
Meriam, J. L., Kraige, L.G..(2008). Engineering Mechanics: Dynamics, Sixth Edition, ISBN-13: 978- 0471787037, New York.