In this course, main methods of machines design are presented. Also, the integration of these methods into the production scheme of a company in order to increase the quality and profitability of their products is studied.



The mechanical design and analysis is a classic mechanical engineering task. It involves obtaining a component, assembly, machine or structure based on the required technical specifications, using generally qualitative and subjective criteria, based on experience and company. Calculations in this phase, if any, such as kinematic and dynamic resistant, thermal, etc., are usually relatively simple and merely indicative, without going into detail. The working tool is a program of computer-aided design, CAD (Computer Aided Design).



In design tasks, apart from experience, the engineers mainly use their knowledge of subjects such as technical drawing, geometry, applied mechanics, machine parts, construction elements, manufacturing technologies, different standards and engineering projects.



Once a component, assembly, machine or structure has been designed, analysis techniques try to simulate its mechanical behaviour in service. Today, in the analysis phase, the computer is widely used, with programs mainly based on finite element techniques, FEA (Finite Element Analysis) and others similar.



In this phase, the engineer uses his expertise on kinematics and dynamics, elasticity and mechanics of materials, thermodynamics, fluid mechanics, fatigue, methods of computational analysis, theory of structures and specific knowledge of the type of machine or structure that he is designing and corresponding calculation standards and protocol of the company in its case.



If necessary, later, prototypes are built and are tested. The results of these tests can be used, at least in part, to improve analysis. Machine Design classes, the knowledge that the student has on materials, elasticity, mechanics of materials and other current and calculation methods are expanded. And actual calculation methods to be able to carry out the analysis of complex mechanical resistant components are presented.



Also in this matter, aspects of specimens and prototypes tests, especially in the field of fatigue problems are studied.

Competences of the subject:



- Knowledge and ability for calculation, design and testing machines.



- Ability to deal developments, projects and advanced studies in the field of mechanical engineering, with a high degree of autonomy.



Learning outcomes:



- Design by finite element method.



- Fatigue failure design.



- Search and select information, communicate orally or in writing, writing reports.

Presentation of the subject

1. Scope of the subject Machine Design

2. Relationship with other subjects in the curriculum; background

3. Subject program

4. Organization of the course; lectures, tutorials, labs, exams





Chapter 1

A first description of the MEF and its use in mechanical design

1. Product Development Cycle

2. Brief historical description and MEF bases

3. Functions of interpolation, natural coordinates and approximate solution.

4. Basic relations in an element

5. Calculation of the stiffness matrix of an element

6. Stiffness matrix model, boundary conditions, properties







Chapter 2

Analysis of two-dimensional models



1. Types and applications of two dimensional analysis in machine design

2. Properties and applications truss and beam elements

3. Triangular and quadrilateral linear element

4. Other elements; higher order and transition



Chapter 3

Analysis of three-dimensional models

1. Overview of three-dimensional analysis

2. Elements bar and beam

3. General considerations on the solid elements

4. Finite element models of plates and shells



Chapter 4

Mechanical properties and material selection



1. Selection of materials

2. Qualitative Properties

3. Quantitative Properties

4. Local effects; stress concentration

5. Stress concentration coefficients

6. Factors that contribute brittle failure in ductile materials



Chapter 5

Safety factor and failure theories in machine design



1. Necessity of the safety factor

2. Influence of material and method of analysis

3. Selection of safety factors

4. Theories of static failure in machine design



Chapter 6

Introduction to material fatigue



1. Analysis with variable solicitations: quasi-static and dynamic cases

2. Background and current status

3. Qualitative aspects of fatigue

4. Fatigue tests



Chapter 7

Material fatigue with uniaxial alternating stresses

1. Theories for fatigue analysis

2. Resistance to fatigue and fatigue limit

3. Modifying factors of fatigue limit

4. Stresses concentration and notch sensitivity

5. Modifying factors for finite life; Basquin equation



Chapter 8

Fatigue analysis with nonzero mean stress



1. Fatigue with mean stresses; Haigh diagram

2. Criteria for the Haigh diagram in ductile materials

3. Criteria for the Haigh diagram in brittle materials

4. Safety factor; equivalence stresses

5. Safety margin; equivalence duration

6. Treatment of stress concentration



Chapter 9

Cumulative damage



1. Cumulative Damage: Palmgren-Miner method

2. Cumulative Damage: modification of Manson

3. Procedures for cycle counting



Chapter 10

Fatigue analysis with multiaxial stress



1. General considerations on multiaxial fatigue

2. Multiaxial simple state with alternating stresses

3. Multiaxial simple state with nonzero mean stresses

4. Classic treatment of complex multiaxial states

5. Methods for global approach and critical plane



Chapter 11

Linear Fracture Mechanics for Fatigue

1. Basic concepts of fracture mechanics

2. Fatigue crack propagation; applying Paris equation

3. Delay effects caused by overload

4. Prediction of crack growth





Computer practices (PO)



Chapter PO1

Practical considerations about finite element programs

1. Organization of a Finite Element program

2. Outline of use of computer program

3. A basic example of modeling



Chapter PO2

Analysis of two-dimensional models

1. Examples with truss and beam elements

2. Examples with two-dimensional elements: plane stress, plane strain, axisymmetric

3. Examples with combination of different types of 2D elements



Chapter PO3

Analysis of three-dimensional models

1. Examples with truss and beam elements

2. Examples with solid elements

3. Examples shell elements

4. Examples with combination of different types of 3D elements



Chapter PO 4

Test and fatigue design practice

1. Computer programs for fatigue analysis

2. Fatigue design using finite element method

3. Comparison and practical considerations

The course consists of lectures, classroom practices and computer practices.



1. Lectures



It is the fundamental part of the subject, teachers expose classroom lessons interacting with students. For the successful use of these classes, students will have previously basic information corresponding to the lesson taught. Classes are primarily based on developments made on the board with computer presentations.



2. Classroom practices

Troubleshooting and practical approach to learning to select the most appropriate design method to each case and apply the methods and calculation procedures outlined in the theory classes and practical method of computer cases.



3. Individual and group tutorials

The tutorial classes serve to elucidate and reinforce those aspects of the subject that need the student, after attending class and done prior study work. The teachers of the subject will be available in the hours devoted to tutoring published in the GAUR application of the UPV / EHU. The place for tutoring will be the office of each professor in the Department of Mechanical Engineering of Bilbao ETSI



4. Virtual Teaching Platform

On the platform egela-EHU is available to the students notes and miscellaneous information to facilitate monitoring of the course. Specifically, the Student Guide, scripts computer practices, exams of previous years are published. Likewise, the establishment of forums will be promoted to encourage student participation and facilitate cooperative learning

• Continuous Assessment System
• Final Assessment System
• Tools and qualification percentages:
  • Written test to be taken (%): 75
  • Team projects (problem solving, project design)) (%): 25

Students will have the opportunity to be evaluated through a single exam, according to the official call. A minimum mark of 5 points out of 10 will be required to pass the subject. In no case will the final exam be held out the official published date. The exam will have 3 tests. The first test will evaluate the knowledge acquired by the student in the first part of the subject, and will have a weight of a 30% over the final mark. The second test will evaluate the knowledge acquired by the student in the second part of the subject, and will have a weight of a 45% over the final mark. The third test will evaluate the knowledge acquired by the student in the computer practices, and will have a weight of a 25% over the final mark.

In the ordinary call, students will also have the opportunity to choose a continuous evaluation according to the next criterion:

- Mid-term exam:

· Weight over the final mark: %30.

· Content: first part of the subject.

· Minimum grade: 3,5 out of 10.

- Final exam:

* If more than 3,5 in the mid-term exam:

· Weight over the final mark: %45.

· Content: second part of the subject.

· Minimum grade: 3,5 out of 10. The average with the mid-term exam must be greater than 5 out of 10 to pass the subject.

* If less than 3,5 in the mid-term exam or to improve previously obtained mark (the mark of the mid-term exam would not be considered in this case):

· Weight over the final mark: %75.

· Content: the whole subject.

· Minimum grade: 5 out of 10.

- Team work:

· Weight over the final mark: %25.

· Content: a design or analysis study of a component using the Finite Element Method. Fatigue analysis methods can also be used.

· Minimum attendance: %80 of the computer classes.

In the extraordinary call, students will be evaluated through a single exam, according to the official call. A minimum mark of 5 points out of 10 will be required to pass the subject. In no case will the final exam be held out the official published date. The exam will consist of a single test, which will include the contents taught both in the theoretical and computer classes.

Regarding the support material for the theoretical content, in the Library of the Engineering School, the student has a very extensive bibliography of consultation on the topics covered in this subject; those students who wish, have available in the Publications Service of the Engineering School the books entitled: " MÉTODOS DE ANÁLISIS PARA DISEÑO MECÁNICO: Vol. II." and " MÉTODOS DE CÁLCULO DE FATIGA PARA INGENIERÍA" Paraninfo publisher. For class problems there are notes in the Publications Department of the School: " CUADERNO DE EJERCICIOS DE CLASE: TECNOLOGÍA DE MATERIALES Y DISEÑO DE MÁQUINAS ". Also, on the website, http://egela.ehu.es, computer practices about finite element method, some figures, previous exam, photographs of interest, links to other pages and content of computer practices are linked.

Basic bibliography

MÉTODOS DE ANÁLISIS PARA DISEÑO MECÁNICO: Vol. II. R. Avilés. Servicio Publicaciones ETSI Bilbao

MÉTODOS DE CÁLCULO DE FATIGA PARA INGENIERÍA. R. Aviles. Ed. Paraninfo. ISBN 9788428335188

CUADERNO DE EJERCICIOS DE CLASE: TECNOLOGÍA DE MATERIALES Y DISEÑO DE MÁQUINAS. Servicio Publicaciones ETSI Bilbao

In-depth bibliography

Norton, R.L.; Machine design, an integrated approach (3rd Edition). Pearson International Edition, 2006.
Deutschmann, A.D.; Michels, W.J.; Wilson, C.E.; Machine design: theory and practice. Macmillan Publishing Co., Inc., 1975.
Spotts, M.F.; Shoup, T.E.; Design of machine elements, 7th edition. Pearson Education, Prentice Hall, 1998.
Shigley, J.E.; Mischke, C.R.; Budynas, R.G.; Mechanical engineering design (7th Edition). McGraw Hill, 2004.
Faupel, J.H.; Fisher, F.E.; Engineering design: a synthesis of stress analysis and materials engineering. Wiley-Interscience, (USA), 1981.
Rothbart, H.A.; Mechanical design & systems handbook 2a Ed.. Mc Graw Hill, (USA), 1985.
Mott, R.L.; Diseño de elementos de máquinas, 2ª Ed.. Prentice may, (Mex), 1992.
Juvinall, R.C.; Marshek, K.M.; Fundamentals of machine component design (3rd Edition). Ed. Wiley, 2000.
Pilkey, W.D.; Peterson's Stress Concentration Factors, 2nd Ed. Wiley Interscience, 1997.
Dowling, N.E.; Mechanical Behavior of Materials: Engineering Methods for Deformation, Fracture, and Fatigue, 2nd Ed. Prentice-Hall, 1999.
Broek, D.; Elementary engineering fracture mechanics. Martinus Nijhoff Publishers, Kluwer Academic Publishers Group, 1984.
Broek, D.; The Practical Use of Fracture Mechanics. Kluwer Academic Publishers, 1988.
Anderson, T.L.;Fracture mechanics; fundamentals and applications. CRC Press (USA), 1995.
Stephens, R.; Fatemi, A.; Stephens, R.R.; Fuchs, H.O.; Metal Fatigue in Engineering, 2nd edition. Wiley, 2001.
Zienckiewicz, O.C.; The finite element method (3' Ed.). Mc Graw-Hill, 1985.
Hughes, T.J.R.; The Finite Element Method; Linear Static and Dynamic Finite Element Analysis. Prentice-Hall International Editions, 1987.
Rao, S.S.; The Finite Element Method in Engineering. Pergamon International Library, 1982.
Avilés, R.; Métodos de Análisis para Diseño Mecánico, Vol. III: Elementos Finitos en Dinámica. Departamento de Publicaciones de la ETSI de Bilbao, 2002.

Journals

International Journal of Fatigue

Finite Elements in Analysis and Design

Web addresses

www.ingenierosbilbao.com
www.biblioteka.ehu.es
http://www.efatigue.com/
http://www.journals.elsevier.com/international-journal-of-fatigue/