Machine Elements II
Code
3676
Academic unit
Faculdade de Ciências e Tecnologia
Department
Departamento de Engenharia Mecânica e Industrial
Credits
6.0
Teacher in charge
António Manuel Flores Romão de Azevedo Gonçalves Coelho, Rui Fernando dos Santos Pereira Martins
Weekly hours
4
Total hours
56
Teaching language
Português
Objectives
The main objectives of Machine Elements II course are:
- To know how to use the graphical and semi-graphical methods, as well as the Cartesian formulation of mechanisms, to determine displacement, velocity, acceleration and forces applied on mechanisms;
- To know how to determine displacement, velocity, acceleration and forces on mechanisms using numerical computer codes (Computer Aided Engineering), such as: SolidWorks, Motion and Simulation.
- To use graphical methods to perform synthesis/design of simple mechanical systems;
- To know how to design axisymmetric pressure vessels submitted to internal and/or external pressure using theoretical equations and the ASME Boiler and Pressure Vessels Code, Section VIII, Division 1.
- To know how to manufacture pressure vessels, including cut, bending and welding of shells. Stress relief treatments, as well as non-destructive testing, will be studied.
- To know how to calculate the hydrostatic pressure test value and the detailed procedures to perform the test.
- To determine deflections, stresses and strains induced on plates using the Navier and the Rayleigh-Ritz methods.
Prerequisites
n/a
Subject matter
Mechanism and machine theory: cartesian formulation, graphical and semi-graphical methods for the analysis of displacement, velocity and acceleration of mechanisms. Kinetostatics and dynamics of machines. Graphical methods for the synthesis of mechanisms with 2 and 3 coordinate positions. Numerical simulation of mechanisms using computer aided engineering software, such as: SolidWorks, CosmosMotion and Simulation/Ansys.
Pressure vessels: design and fabrication of axisymmetric pressure vessels. Introduction to its design through standards, such as ASME Boiler and Pressure Vessels Code, Section VIII, Division 1 and EN 13445 - Unfired pressure vessels.
Theory of thin plates: calculation of deflections, stresses and strains using the Navier and the Rayleigh-Ritz Methods.
Bibliography
Schwamb, P., Merril, J. & Doughtie, "Nociones de Mecanismos", Ed. Aguilar S.A. (1985)
Bednar, Henry H., "Pressure vessel design handbook", Ed. Van Nostrand Reinhold Company (1991)
Ugural, Ansel C., "Stresses in plates and shells", 2a Edição, McGraw-Hill International Editions (1999)
Advanced Strength of Materials, den Hartog, McGraw-Hill
Teaching method
The oral exposition is the teaching method mainly used, associated with sketches, schemes and resumes made by the teacher in the classroom''''s blackboard. The video projector is also used in the classroom. In the practical classes, the teacher solves representative problems to introduce the strategies of resolution of exercises to the students. Then, other exercises are presented and a time period is fixed to its resolution. The teacher will attend any doubts during this period. All exercises are solved in the blackboard and are commented.
The lab experiments have two main objectives, namely, to compare theoretical with experimental/numerical results and to give the students the possibility to gain some practical experience. The lab experiments and the numerical simulations will also allow the students to review all the subjects taught during the semester.
Evaluation method
The evaluation of students is carried out through a Theoretical and Practical Assessment, which includes two tests, T1 and T2, and a Laboratory or Project Assessment, which includes a laboratory work, TL, and a computational work, CT.
The final classification, NF, obtained through continuous assessment, will be calculated according to the following formula:
NF = 0.25 x T1 + 0.25 x T2 + 0.25 x TL + 0.25 x TC
where T1 and T2 represent the classifications, rounded to one decimal place, obtained in Tests 1 and 2, respectively, while TL and TC represent the classifications, rounded to one decimal place, obtained in the laboratory work and in the computational work, respectively.
The acquisition of frequency, valid for one year, is dependent on obtaining a weighted average equal to or higher than 9.5 in the two elements of assessment related to the Laboratory or Project Assessment components.
With regard to the Theoretical-Practical evaluation, a weighted average equal to or higher than 9.5 in the two tests is required.
The first test and the laboratory work should be carried out until the 8th week of the 1st semester. The laboratory work and the computational work can be done in groups (maximum number of students / group: 3).
If a student does not reach the minimum score required in the Theoretical-Practical Component Evaluation during the period of continuous assessment, but have obtained frequency, the student may carry out an exam during Appeal, Special and Extraordinary Seasons. The exam will be divided into two parts, Exam(T1) and Exam(T2), relating to the subjects of the two tests carried out during the continuous assessment period. In this case, the calculation of the final classification will be done using the following formula:
NF = 0.25 x Exam (T1) + 0.25 x Exam (T2) + 0.25 x TL + 0.25 x TC
where Exam (T1) and Exam (T2) represent the classifications, rounded to one decimal place, obtained in Exam (tests 1 and 2, respectively), while TL and TC represent the classifications, rounded to one decimal place, obtained in laboratory work and in computational work, respectively. A weighted average, equal to or higher than 9.5, must be obtained in Exam (T1) and Exam (T2) in order to be approved.
During the first test and the exam (test 1), the usage of three sheets, exclusively related to thin plates theory and thin shells theory, is allowed. The form must be handwritten.