Use strength of materials in engineering


This unit describes the performance outcomes, skills and knowledge required to determine stresses and deformations in selected components using the principles of strength of materials.

The unit of competency is applied by technicians in a civil and structural engineering environment operating as part of an engineering design team.

No licensing, legislative, regulatory or certification requirements apply to this unit at the time of publication.

  • DCSSTA607 Use statics in engineering
  • DCSBME604 Use basic mathematics in engineering


Elements describe the essential outcomes.


Performance criteria describe the performance needed to demonstrate achievement of the element.

1.    Evaluate a bolted joint.

1.1.      Determine shear strength of the bolt group.

1.2.      Determine bearing strength of the bolt group.

1.3.      Determine tensile strength of the components and the joints.

2.    Evaluate a welded joint.

2.1.      Determine strength of weld per unit length.

2.2.      Determine required length and distribution of weld.

3.    Evaluate thin-walled pressure vessels.

3.1.      Calculate hoop and longitudinal stresses of a pressure vessel.

3.2.      Apply stress calculations to determine the optimum wall thickness of a pressure vessel.

4.    Design shafts to transmit a torque.

4.1.      Determine required strength criteria

4.2.      Determine required deformation criteria

5.    Design beams for flexural strength and deflections.

5.1.      Determine flexural strength criteria

5.2.      Determine required deformation criteria

6.    Determine thermal stresses in restrained members.

6.1.      Calculate thermal stresses in a restrained member.

6.2.      Calculate thermal stresses in a restrained member when subjected to a change in temperature


Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.


41982 Use strength of materials in engineering is equivalent.



Assessment requirements for DCSSOM615 Use strength of materials in engineering


To achieve competency in this unit a person must satisfy the requirements of the elements and performance criteria, foundation skills and range of conditions included in the unit.

The person must also:

  • Complete at least 1 drawing of a shaft, a pressure vessel and a beam, individually or together, where
    • correct design capacity of joints is determined.
    • correct maximum stress is determined in members.
    • correct deformations of members are determined.
    • angles of twist in shafts subject to torsion are indicated.
    • deflection of beams at critical positions are indicated when subjected to a combination of distributed and concentrated loads.
    • sizes of components (bolts, welds, cleats) in joints are correctly indicated

Note: If a specific volume or frequency is not stated, then evidence must be provided at least once for each criterion.


To achieve competency in this unit, a person must demonstrate knowledge of:

  • Key principles for applying strength of materials to design, including:
  • differences between a working stress approach and a limit state (ultimate strength) approach to design.
  • formulas to determine
    • perimeter,
    • area(A),
    • first moment of area(Q),
    • position of the centroid,
    • second moment of area (moment of inertia I),
    • radius of gyration(r),
    • elastic modulus(Z) and
    • the plastic modulus(S) of plane sections that can be constructed by combining a number of rectangular or circular shapes.
  • the parallel axis theorem to determine the second moment of area about a non-centroidal axis.
  • formula to determine the flexural stress at any point in a beam.
  • formula to determine hoop and longitudinal stresses in pressure vessels.
  • formula to determine shear stresses at any point in a shaft subject to torsion.
  • formula to determine the angle of twist of a shaft subjected to torsion.
  • formulae to determine the max deflection of either simply supported beams or cantilever beams subjected to either a uniformly distributed load or a concentrated load (centrally located for a simply supported beam or located at the free end for a cantilever).
  • theorems 1 and 2 of the area moment method for determining beam deflections.
  • Simpson’s rule for determining areas under a curve and in its modified version to determine the first moment of an area under a curve.
  • formula to determine the thermal expansion of unrestrained members subject to a temperature change.


Assessment conditions:

All assessment must be completed in accordance with work health and safety standards.

When assessments are conducted remotely, invigilation software must be used to ensure authenticity of work completed.

Model answers or marking guides must be provided for all assessments to ensure reliability of assessment judgements when marking is undertaken by different assessors.

The candidate must have access to all tools, equipment, materials and documentation required.

Assessor Requirements:

Assessors must satisfy the assessor requirements in the standards for registered training organisation (RTOs) current at the time of assessment.

Assessors must also hold a tertiary qualification in engineering or related field.

Assessors must have worked for at least 3 years in industry where they have applied the skills and knowledge covered in this unit of competency.

The RTO must also ensure that trainers and assessors keep their industry knowledge up to date through ongoing professional development.

The RTO must take appropriate steps, as an ongoing procedure, to verify information about trainer and assessor’s qualifications, vocational competencies and current industry skills


Software/Hardware Used


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