Callum Pickard Portfolio

Domestic Boiler Thermal Fatigue

During a water heating cycle, the back of the combustion chamber was found to be buckling under

thermal stresses. The client required the expected fatigue life to be calculated assuming 30 cycles

per day, determined to be just under 10 years, and will fail around the pop rivets.

Temperature Distribution

Thermal Expansion Stresses (x10 exaggerated)

Areas of Stress Higher Than Yield Strength

Cyclone Dust Box Pressure Analysis

To clean the dust box, gas will be used at high pressure. Using FEA, 1 MPa of internal pressure was

applied and scaled to determine the MAWP to be used to clear the dust.

3D Model of Dust Box

Stress Distribution

Areas of High Stress

Diverter Box

This diverter box has an operating pressure of 0.5 barg, and this needed to be assessed for safety.

The maximum safe pressure was determined to be 1.14 barg.

3D Model of Diverter

Stress Distribution Under 0.5 barg

The client then came back with the issue of an explosion case. The box could be subjected to 10 barg

if an explosion were to happen in the same pipeline. If the diverter were to rupture, this would

endanger workers, so additional stiffening ribs needed to be added to improve the pressure

resistance of the diverter. After a few iterations, a new design was created.

3D Model with Addition Shown in Red

Stress Distribution Under 10 barg

Water Pump API 610 Certification

To verify if the pump met the API 610 code, the MAWP is applied to the internal face as well as a set

of nozzle loads are applied to the inlet and outlet flanges. The worst case scenario was determined

by analysing each nozzle load separately and them combining them in envelope studies.

The pump was found to fail at the cutwater, but as these stresses will not cause any detrimental

effects, the pump was found as meeting the code.

Shaft alignment was also a concern for the client, so the displacements were calculated and it was

determined that the bearings would allow for such small movements.

3D Model and Section View of Radial Pump

Stress Distribution Capped at 100 MPa – Safe Stress in API 610

Maximum Vertical Distribution – 0.1 mm

Firewater Vibration Analysis

Firewater pumps on oil rigs must ensure that their running speeds have a separation margin of 20%

with the natural frequencies of the pump. The first natural frequency of this particular pump was

7573 rpm, compared to the running speed of 1470 rpm, which clearly passes the code.

Pump Model and Dimensions

Mode Shapes of Natural Frequencies

Auger Piling Mast Analysis

A mast attached to a hydraulic arm was to be used for auger mast piling, and the limiting loads on

each component needed to be assessed. Due to the simple geometry and complex loading, hand

calculations were used to determine the limits. A known limit was the rupture strength of the cable

used to winch the auger up and down, so if the allowable load for a case exceeded this, it was

regarded as safe. Bending and buckling load cases for the mast and auger sled all surpassed this limit

clearly. The sheave pin was found to be the weakest part by far, so the support was altered to

reduce this stress.

Auger Piling Mast Model

Calciner Temperature Study

Working as part of a team, my section was to create the temperature distribution of a calciner

operating at over 1000oC. This was done using a combination of Thermal FEA and Rayleigh

calculations. The inlet temperature was found to be different to reality as the information about the

cold feedstock constantly added.

Shell Model of Calciner

Temperature Distribution

Ground Mat Analysis

For use on construction site to protect the ground, large plastic mats are used. The load capacity of

these were analysed using linear analogues for varied soil stiffness and applying a tyre contact area.

The load capacity was found to increase with soil stiffness.

3D Model of Mat on Soil

Stress Distribution within Mat

For more boggy soils, a cellular mat, constructed in two halves, was being developed to create a

buoyant surface. To analyse a cellular mat takes significantly more computing power, so a solid

analogue of the mats were created. A small section of the mat was modelled explicitly to calculate

an effective modulus for the cells, and the effect of a bolt or plug connecting the two halves of the

mat.

Cantilever Bend Test to Create Analogue

Shear Test to Create Bolt Analogue

Shear Test to Create Plug Analogue