SCEE08002 Structural Mechanics 2 Laboratories Assignment Guidance | UOE

Exercise 1: Composite Action in a Beam

Data Collection

1. Setup:

• Apparatus investigates Euler’s Beam Theory.
• Test two beam types:

• Bonded (steel + aluminium glued).
• Unbonded (steel + aluminium not glued).

2. Procedure:

• Zero the strain gauge.
• Incrementally load weights (30N to 150N) and record strain data for each strain gauge.

3. Report Content:

• Two Tables:

• One for bonded beam.
• One for unbonded beam, showing weight and strain gauge readings.

Analysis

1. Tasks:

• Write an expression for the force FFF in terms of weight WWW, dimensions mmm, and nnn.
• Could you write an expression for the bending moment MMM at mid-span?
• Plot strain vs. vertical position for the 150N load for both beams and theoretical predictions.

2. Report Content:

• Two tables (moment and strain gauge readings).
• One graph (experimental vs. theoretical strain).
• Explanation of behavior differences between bonded and unbonded beams.

Exercise 2: Torsion of a Shaft

Data Collection

1. Setup:

• The apparatus measures rotation response to torque.
• Test aluminium and steel bars at two lengths (300mm and 160mm).

2. Procedure:

• Record shaft rotation for weights (0.25kg and 0.5kg).
• Measure lever arm and shaft diameters.

3. Report Content:

• Table showing rotation readings for each setup.
• Notes on lever arm and shaft diameters.

Analysis

1. Tasks:

• Convert weights to torque.
• Estimate shear modulus for materials based on rotation vs. torque plots.

2. Report Content:

• Table (mass, torque, rotation, length).
• Graphs (rotation vs. torque for all setups).
• Calculations and error discussion.

Exercise 3: Membrane Stresses in a Pressure Vessel

Data Collection

1. Setup:

• Thin-walled cylinder (aluminium) subjected to internal pressure.
• Strain gauges measure strain in axial and tangential directions.

2. Procedure:

• Record strain readings for:

• Closed condition: Bi-axial stress.
• Open condition: Uni-axial stress.

3. Report Content:

• Table showing strain for both conditions.

Analysis

1. Tasks:

• Predict longitudinal and hoop stresses.
• Draw Mohr’s circle for each condition.
• Calculate yield pressure and theoretical hoop strain.
• Compare predictions with experimental strains

2. Report Content:

• Mohr’s circle (theoretical).
• Yield pressure calculation.
• Hoop and longitudinal strain calculations.
• Comparison and error discussion.