Unit 62 Strengths of Materials


 

Unit 62:

Strengths of Materials

 

Unit code:
K/601/1409

QCF level:
5


Credit value:
15






Aim

This unit will enable learners’ to use stress analysis techniques to determine the behavioural characteristics of engineering components and materials.

Unit abstract

This unit will introduce learners to the theoretical and experimental methods of complex stress analysis, together with the theories of elastic failure. Appropriate use of these can be made throughout the unit to determine operational factors of safety. Learners will investigate the theoretical behaviour of structural members under load and will verify the characteristics by experimental testing. They will then analyse loaded structural members from considerations of strain energy and again carry out experimental verification of the analysis.

Learning outcomes

On successful completion of this unit a learner will:

1       Be able to determine the behavioural characteristics of engineering components subjected to complex loading systems

2       Be able to determine the behavioural characteristics of loaded beams, columns and struts

3       Be able to determine the behavioural characteristics of loaded structural members by the consideration of strain energy.


Unit content

1      Be able to determine the behavioural characteristics of engineering components subjected to complex loading systems

Complex stress: analysis of two-dimensional stress systems eg determination of principal planes and stresses, use of Mohr’s stress circle; combined torsion and thrust; combined torsion and bending

Complex strain: Mohr’s strain circle; experimental strain analysis using electrical resistance strain gauges

Theories of elastic failure: maximum principal stress theory; maximum shear stress theory; strain energy theory and maximum principal strain theory

2      Be able to determine the behavioural characteristics of loaded beams, columns and struts

Simply supported beams: use of Macaulay’s method to determine the support reactions, slope and deflection due to bending in cantilevers and simply supported beams with combined concentrated and uniformly distributed loads

Reinforced concrete beams: theoretical assumptions; distribution of stress due to bending

Columns: stress due to asymmetrical bending; middle third rule for rectangular section columns and walls; middle quarter rule for circular section columns

Struts: end fixings; effective length; least radius of gyration of section; slenderness ratio; Euler and Rankine-Gordon formulae for determination of critical load

3      Be able to determine the behavioural characteristics of loaded structural members by the consideration of strain energy

Strain energy: strain energy stored as a result of direct loading, shear loading, bending and torsion

Elastic deflections: elastic deflection of struts and ties when subjected to gradually applied loads; elastic deflection at the point of loading for cantilevers and simply supported beams when subjected to a single gradually applied load; application of Castigliano’s theorem to determine deflection eg beams, brackets, portal frames and curved bars when subjected to gradually applied loads; elastic deflection of torsion bars and transmission shafts subjected to a gradually applied torque

Shock loading: elastic deflection and stress induced in struts and ties when subjected to suddenly applied loads and impact loads

Learning Outcomes and assessment criteria




Learning outcomes
Assessment criteria for pass


On successful completion of
The learner can:


this unit a learner will:










LO1 Be able to determine the

1.1
analyse two-dimensional stress systems making


behavioural characteristics of


appropriate use of Mohr’s stress circle


engineering components

1.2
carry out experimental strain analysis using electrical


subjected to complex loading





resistance strain gauges


systems











1.3
apply the appropriate theory of elastic failure to





loaded components to determine operational factors





of safety








LO2 Be able to determine the

2.1
determine the support reactions, slope and


behavioural characteristics of


deflection of simply supported beams


loaded beams, columns and

2.2
determine the distribution of stress in the materials


struts





of reinforced concrete beams









2.3
determine the stress distribution in columns and





walls which are subjected to asymmetrical bending




2.4
determine the appropriate critical load for axially





loaded struts




2.5
carry out tests to validate critical load calculations







LO3 Be able to determine the

3.1
determine the strain energy stored in a member due


behavioural characteristics of


to direct loading, shear loading, bending and torsion


loaded structural members by

3.2
determine the elastic deflection of loaded members


the consideration of strain





making appropriate use of Castigliano’s theorem


energy











3.3
carry out tests to validate deflection calculations




3.4
predict the effects of shock loading on struts and





ties.










Guidance
Links

This unit is intended to provide progression from Unit 2: Engineering Science and Unit 4: Mechanical Principles.

Essential requirements

Centres need to provide access to laboratory facilities so that learners can investigate the effects of loading on structural members and engineering components.

Employer engagement and vocational contexts

The delivery of this unit will benefit from centres establishing strong links with employers willing to contribute to the delivery of teaching, work-based placements and/or detailed case study materials.

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