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MECH8012 - Mechanical Materials (3D)

Title:Mechanical Materials (3D)
Long Title:Mechanical Materials (3D)
Module Code:MECH8012
Duration:1 Semester
Credits: 5
NFQ Level:Advanced
Field of Study: Mechanical Engineering
Valid From: Semester 1 - 2016/17 ( September 2016 )
Module Delivered in 1 programme(s)
Module Coordinator: MATTHEW COTTERELL
Module Author: Sean F OLeary
Module Description: This module will cover three dimensional mechanical linear elastic and non-linear elastic/plastic analysis and design, from first principles, of rotating and statically loaded structures including curved bars, thick pressure vessels, solid and hollow discs, beams, shafts and portal frameworks. Finite element modelling of 3D stess analysis application is introduced by hands on computer aided design laboratory.
Learning Outcomes
On successful completion of this module the learner will be able to:
LO1 Determine the fundamental governing/transformation relations of three dimensional strength of materials analysis.
LO2 Analyse 3D mechanical linear elastic structures for critical elastic design parameters.
LO3 Analyse non-linear elastic/plastic mechanical structures for critical plastic design parameters.
LO4 Apply and interpret computer based finite element modelling of stress/ strain displacement application.
LO5 Review, undertake analysis of and report on strength of materials applications.
Pre-requisite learning
Module Recommendations
This is prior learning (or a practical skill) that is strongly recommended before enrolment in this module. You may enrol in this module if you have not acquired the recommended learning but you will have considerable difficulty in passing (i.e. achieving the learning outcomes of) the module. While the prior learning is expressed as named CIT module(s) it also allows for learning (in another module or modules) which is equivalent to the learning specified in the named module(s).
Mechanical Materials (2D)
Incompatible Modules
These are modules which have learning outcomes that are too similar to the learning outcomes of this module. You may not earn additional credit for the same learning and therefore you may not enrol in this module if you have successfully completed any modules in the incompatible list.
No incompatible modules listed
Co-requisite Modules
No Co-requisite modules listed

This is prior learning (or a practical skill) that is mandatory before enrolment in this module is allowed. You may not enrol on this module if you have not acquired the learning specified in this section.

No requirements listed

Module Content & Assessment

Indicative Content
Introduction to Non-Linear/Plastic Material Behaviour
Rigid/plastic, rigid/elastic, elastic/plastic material behaviour. Tensile testing. Relationships between nominal/true stress/strain. Power law plasticity behaviour. Experimental determination of work hardening and strength coefficients. Considere’s method. Elastic/plastic work done. Strain energy stored.
Three Dimensional Stress/Strain Analysis
Introduction to the theory of Elasticity: equations of equilibrium in 3D. The stress tensor. Variation of stress within a body. Two and three dimensional Stress at a point. Principal stresses in three dimensions. Matrix rotation method. Matrices solution techniques for magnitudes and direction cosines of principal stresses. Cofactors of determinant method. Stresses on an oblique plane in terms of principal Stresses. Octahedral shearing stress. Mohr’s Circle of 3D stress. Stress-strain relations. Equation of compatibility in 3D. State of strain at a point.
Theories of Failure and Fracture
Function of theories. Maximum principal stress/maximum shear stress/maximum principal strain/total and shear strain energy theories of elastic failure. Comparison of the yielding theories. Graphical representations. 3D envelopes of failure. Load-line solutions. Theories of fracture.
Fatigue Strength Evaluation
Failure criteria for fatigue. Soderberg, Gerber, modified Goodman, SAE criteria. Combined states of stress. Maximum and minimum stress tensor fatigue life evaluation. Composite strength. Impact performance and fatigue strengths of metals and composites.
Curved Bar Analysis
Simple bending theory for bars of small initial curvature. Non-linear stress evaluation in bars of large initial curvature of rectangular, trapezoidal and circular cross-sections. Comparison with photoelastic determination of curved bar stresses. Application of Castigliano’s Theorem to the solution of elastic deflections and statically indeterminate members and structures. Concepts of strain energy due to thrust, shear force and bending moment. Evaluation of shear force correction factors. Use of dummy loads. Calculation of deflections/redundant forced in curved bars / comparison with experimentally determined deflections.
Thick-Walled Vessel Analysis
Development of Lamé theory. Variation of circumferential, radial and longitudinal stresses in thick-walled cylinders. Principal/maximum shear stress in 3D. Change of dimensions and volume. Comparison of thin/thick vessel theory. Limitations of applicability. Lamé line graphical treatment. Application of boundary condition approach to solution of Lamé constants. Compound cylinders. Shrinkage/interference allowances. Force fit. Hub on solid shaft. Uniform heating of compound cylinders of different materials. Application of failure/fatigue theories to pressurised vessels.
Rotating Structures
Development of theory for variation of stresses in rotating solid and hollow discs. Determination of location and magnitude of maximum design stresses for thin-walled plane stress rotating structures. Application of plane stress/plane strain transformations to develop theory for variation of stresses in rotating thick cylinders and solid shafts. Rotating disc of uniform strength. Combined rotational and thermal stresses in uniform discs and thick cylinders including linear thermal variation and steady heat flow applications.
Plastic Design Theory
Assumptions in plastic theory, plastic bending of beams, elastic design moment, partially plastic moment, fully plastic moment, plastic hinge, shape factor. Symmetrical and unsymmetrical sections. Deflection of partially plastic beams. Residual stresses. Collapse mechanisms, collapse load and load factors. Plastic torsion, elastic design torque, partially plastic torque, fully plastic torque in solid and hollow shafts. Angle of twist of shapes in plastic torsion. Case-hardened shafts. Residual stresses in plastic torsion. Autofrettage of thick cylinders. Tresca criterion. Plastic penetration of pressurised cylinders. Development of theory analysing variation of circumferential, radial and longitudinal stresses in plastic and elastic regions under autofrettage pressure. Residual and working stress distributions. Plastic theory for frames. Theorem of independent mechanisms. Determination of load factor through combination of mechanisms.
Finite Element Analysis Laboratory
Introduction to Finite Element Analysis. Hands On Computer Laboratory Finite Element Stress/Strain/Displacement Analysis Application. Interpretation of Results.
Assessment Breakdown%
Course Work30.00%
End of Module Formal Examination70.00%
Course Work
Assessment Type Assessment Description Outcome addressed % of total Assessment Date
Short Answer Questions 3D Stress Analysis Fundamentals 1,2,5 15.0 Week 5
Written Report Finite Element Stress/Strain/Displacement Analysis Application Laboratory 2,3,4,5 15.0 Week 10
End of Module Formal Examination
Assessment Type Assessment Description Outcome addressed % of total Assessment Date
Formal Exam End-of-Semester Final Examination 1,2,3,5 70.0 End-of-Semester
Reassessment Requirement
Repeat examination
Reassessment of this module will consist of a repeat examination. It is possible that there will also be a requirement to be reassessed in a coursework element.

The institute reserves the right to alter the nature and timings of assessment


Module Workload

Workload: Full Time
Workload Type Workload Description Hours Frequency Average Weekly Learner Workload
Lecture Theoretical Development and Analysis 3.0 Every Week 3.00
Tutorial Worked Numerical Examples and Problems 1.0 Every Week 1.00
Independent & Directed Learning (Non-contact) Self Directed Study 2.5 Every Week 2.50
Lab Finite Element Analysis Application Laboratory 2.0 Every Month 0.50
Total Hours 8.50
Total Weekly Learner Workload 7.00
Total Weekly Contact Hours 4.50
This module has no Part Time workload.

Module Resources

Recommended Book Resources
  • Hearn E.J. 1997, Mechanics of Materials Volume 2, 3rd Edition Ed., Butterworth Heinemann [ISBN: 0 7506 3266 6]
  • Ugural A.C., Fenster S.K. 2011, Advanced Mechanics of Materials and Applied Elasticity, 5th Ed., Prentice Hall [ISBN: 0 1370 79206]
  • Craig R.R. 2011, Mechanics of Materials, 3rd Edition Ed., Wiley [ISBN: 0 4704 81811]
  • Cook R.D., Malkus D.S., Plesha M.E. 2007, Concepts and Applications of Finite Element Analysis, 4th Edition Ed., Wiley [ISBN: 8126513365]
Supplementary Book Resources
  • Mark E. Tuttle 2013, Structural Analysis of Polymeric Composite Materials, Second Edition, 2nd Edition Ed., CRC Press [ISBN: 143987512X]
  • Boresi A.P., Chong K., Lee J.D. 2010, Elasticity in Engineering Mechanics, 3rd Edition Ed., Wiley [ISBN: 0 470 402 555]
  • Goodno B.J., Gere J.M. 2014, Mechanics of Materials, 8th Ed., Engage Learning [ISBN: 1111136031]
  • Hinton M., Soden, P.D., Kaddour A.S. 2004, Failure Criteria in Fibre-Reinforced Polymer Composites, Elsevier Science [ISBN: 0 08 044475 X]
  • Solecki R., Conant R.J. 2003, Advanced Mechanics of Materials, 1st Edition Ed., Oxford University Press [ISBN: 0 1951 4372 0]
  • Benham P.P., Crawford R.J., Armstrong C.G. 1996, Mechanics of Engineering Materials, 2nd Edition Ed., Longman [ISBN: 0 5822 5164 8]
  • Coates R.C., Coutie M.G., Kong F.K. 1990, Structural Analysis, 3rd Edition Ed., E. & F.N. Spon [ISBN: 0 2780 0035 3]
  • Ward I.M., Sweeney J. 2004, An Introduction to the Mechanical Properties of Solid Polymers, 2nd Edition Ed., Wiley [ISBN: 0 4714 9626 7]
This module does not have any article/paper resources
Other Resources

Module Delivered in

Programme Code Programme Semester Delivery
CR_EMECH_8 Bachelor of Engineering (Honours) in Mechanical Engineering 5 Mandatory

Cork Institute of Technology
Rossa Avenue, Bishopstown, Cork

Tel: 021-4326100     Fax: 021-4545343
Email: help@cit.edu.ie